Review Article | Published:

Molecular biology of bladder cancer: new insights into pathogenesis and clinical diversity

Nature Reviews Cancer volume 15, pages 2541 (2015) | Download Citation


Urothelial carcinoma of the bladder comprises two long-recognized disease entities with distinct molecular features and clinical outcome. Low-grade non-muscle-invasive tumours recur frequently but rarely progress to muscle invasion, whereas muscle-invasive tumours are usually diagnosed de novo and frequently metastasize. Recent genome-wide expression and sequencing studies identify genes and pathways that are key drivers of urothelial cancer and reveal a more complex picture with multiple molecular subclasses that traverse conventional grade and stage groupings. This improved understanding of molecular features, disease pathogenesis and heterogeneity provides new opportunities for prognostic application, disease monitoring and personalized therapy.

Key points

  • Bladder cancer is the fifth most common cancer in men in Western countries (male:female ratio is 3:1), and tobacco smoking is a major risk factor.

  • There are two major groups of patients with distinct prognosis and molecular features. Although local disease recurrence is a major problem for those with low-grade non-muscle-invasive tumours, life expectancy is long and development of invasive disease is infrequent. For those who present with muscle-invasive disease, development of metastatic disease is common, prognosis is dismal and no advances in therapy have been made for decades.

  • Major unmet clinical needs include non-invasive methods for disease surveillance and novel approaches to eliminate both tumour and widespread intraepithelial preneoplasia in patients with non-muscle-invasive disease. New systemic therapeutic approaches are urgently needed for those with muscle-invasive disease.

  • Recent studies reveal important biological features of urothelial metastasis and the epithelial–mesenchymal transition that may contribute to metastatic initiation. A key role for inflammatory processes is evident in the development of metastasis.

  • Heterogeneity in outcome within the two major groups indicates a need for subclassification for more accurate prognostication, prediction of response to current therapies and development of novel therapies.

  • Recent molecular analyses now provide such subclassification with definition of multiple subgroups that are independent of conventional histopathological definitions. This presents major opportunities for personalized patient care.

Access optionsAccess options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.


  1. 1.

    et al. Estimates of worldwide burden of cancer in 2008: GLOBOCAN 2008. Int. J. Cancer 127, 2893–2917 (2010).

  2. 2.

    , , , & Urinary bladder cancer susceptibility carkers. What do we know about functional mechanisms? Int. J. Mol. Sci. 14, 12346–12366 (2013). This is an excellent review of findings of genome-wide association studies in bladder cancer and possible functional mechanisms.

  3. 3.

    Union Internationale Contre le Cancer (UICC) in TNM Classification of Malignant Tumors 7th edn 262–265 (UICC, 2009).

  4. 4.

    , , & World Health Organization Classification of Tumours. Pathology and Genetics of Tumours of the Urinary System and Male Genital Organs (IARC Press Lyon, 2004).

  5. 5.

    World Health Organization. Histological Typing of Urinary Bladder Tumours. (WHO, 1973).

  6. 6.

    , , & Treated history of noninvasive grade 1 transitional cell carcinoma. The National Bladder Cancer Group. J. Urol. 148, 1413–1419 (1992).

  7. 7.

    et al. Predicting recurrence and progression in individual patients with stage Ta T1 bladder cancer using EORTC risk tables: a combined analysis of 2596 patients from seven EORTC trials. Eur. Urol. 49, 466–477 (2006).

  8. 8.

    Bladder cancer: lack of progress in bladder cancer — what are the obstacles? Nature Rev. Urol. 10, 5–6 (2013).

  9. 9.

    et al. Whole-genome sequencing identifies genomic heterogeneity at a nucleotide and chromosomal level in bladder cancer. Proc. Natl Acad. Sci. USA 111, E672–E681 (2014).

  10. 10.

    , , , & DNA double strand break repair in human bladder cancer is error prone and involves microhomology-associated end-joining. Nucleic Acids Res. 32, 5249–5259 (2004).

  11. 11.

    et al. Recurrent inactivation of STAG2 in bladder cancer is not associated with aneuploidy. Nature Genet. 45, 1464–1469 (2013).

  12. 12.

    et al. Frequent truncating mutations of STAG2 in bladder cancer. Nature Genet. 45, 1428–1430 (2013).

  13. 13.

    , , , & Frequent inactivating mutations of STAG2 in bladder cancer are associated with low tumor grade and stage and inversely related to chromosomal copy number changes. Hum. Mol. Genet. 23, 1964–1974 (2013).

  14. 14.

    et al. Mutational inactivation of STAG2 causes aneuploidy in human cancer. Science 333, 1039–1043 (2011).

  15. 15.

    , & CTCF and cohesin cooperate to organize the 3D structure of the mammalian genome. Proc. Natl Acad. Sci. USA 111, 889–890 (2014).

  16. 16.

    et al. Distinct functions of human cohesin-SA1 and cohesin-SA2 in double-strand break repair. Mol. Cell. Biol. 34, 685–698 (2014).

  17. 17.

    et al. Whole-genome and whole-exome sequencing of bladder cancer identifies frequent alterations in genes involved in sister chromatid cohesion and segregation. Nature Genet. 45, 1459–1463 (2013).

  18. 18.

    et al. Rates of p16 (MTS1) mutations in primary tumors with 9p loss. Science 265, 415–417 (1994).

  19. 19.

    , , , & p16 (CDKN2) is a major deletion target at 9p21 in bladder cancer. Hum. Mol. Genet. 4, 1569–1577 (1995).

  20. 20.

    , , , & Alteration of the PATCHED locus in superficial bladder cancer. Oncogene 22, 2967–2971 (2003).

  21. 21.

    , , , & PTCH gene mutations in invasive transitional cell carcinoma of the bladder. Oncogene 17, 1167–1172 (1998).

  22. 22.

    , , & Structure and methylation-based silencing of a gene (DBCCR1) within a candidate bladder cancer tumor suppressor region at 9q32–q33. Genomics 48, 277–288 (1998).

  23. 23.

    , , & A sequence-ready 840-kb PAC contig spanning the candidate tumor suppressor locus DBC1 on human chromosome 9q32-q33. Genomics 59, 335–338 (1999).

  24. 24.

    et al. Spectrum of phosphatidylinositol 3-kinase pathway gene alterations in bladder cancer. Clin. Cancer Res. 15, 6008–6017 (2009).

  25. 25.

    et al. A systematic study of gene mutations in urothelial carcinoma; inactivating mutations in TSC2 and PIK3R1. PLoS ONE 6, e18583 (2011).

  26. 26.

    et al. Prognostic value of loss of heterozygosity at chromosome 9p in non-muscle-invasive bladder cancer. Urology 76, e513–e518 (2010).

  27. 27.

    , , & p16 immunoreactivity is an independent predictor of tumor progression in minimally invasive urothelial bladder carcinoma. Eur. Urol. 47, 463–467 (2005).

  28. 28.

    et al. Loss of p16 expression and chromosome 9p21 LOH in predicting outcome of patients affected by superficial bladder cancer. J. Surg. Res. 143, 422–427 (2007).

  29. 29.

    , , & p16INK4A and p19ARF act in overlapping pathways in cellular immortalization. Nature Cell Biol. 2, 148–155 (2000).

  30. 30.

    The INK4a/ARF locus in murine tumorigenesis. Carcinogenesis 21, 865–869 (2000).

  31. 31.

    et al. CDKN2A homozygous deletion is associated with muscle invasion in FGFR3-mutated urothelial bladder carcinoma. J. Pathol. 227, 315–324 (2012). This study suggests that deletion of p16 makes a critical contribution to progression of NMIBCs. Subsequent genome sequencing studies (such as reference 37) define a subgroup of MIBCs with this profile.

  32. 32.

    et al. Profiles of the 2 INK4a gene products, p16 and p14ARF, in human reference urothelium and bladder carcinomas, according to pRb and p53 protein status. Hum. Pathol. 35, 817–824 (2004).

  33. 33.

    et al. Level of retinoblastoma protein expression correlates with p16 (MTS-1/INK4A/CDKN2) status in bladder cancer. Oncogene 18, 1197–1203 (1999).

  34. 34.

    et al. p53, 21, pRB, and p16 expression predict clinical outcome in cystectomy with bladder cancer. J. Clin. Oncol. 22, 1014–1024 (2004).

  35. 35.

    et al. A new tumor suppressor role for the Notch pathway in bladder cancer. Nature Med. 20, 1199–1205 (2014).

  36. 36.

    et al. Frequent mutations of chromatin remodeling genes in transitional cell carcinoma of the bladder. Nature Genet. 43, 875–878 (2011). This was the first major whole-exome sequencing study of bladder cancer, which identified frequent mutation of chromatin modifier genes.

  37. 37.

    The Cancer Genome Atlas Research Network. Comprehensive molecular characterization of urothelial bladder carcinoma. Nature 507, 315–322 (2014). This is the most comprehensive analysis of MIBC so far, including whole-exome sequencing, RNA sequencing and profiling of microRNAs, methylation and protein expression. See also references 173 and 194.

  38. 38.

    The bladder cancer genome; chromosomal changes as prognostic makers, opportunities, and obstacles. Urol. Oncol. 30, 533–540 (2012).

  39. 39.

    Molecular subtypes of bladder cancer: Jekyll and Hyde or chalk and cheese? Carcinogenesis 27, 361–373 (2006).

  40. 40.

    Bladder cancer subtypes defined by genomic alterations. Scand. J. Urol. Nephrol. 218, S116–S130 (2008).

  41. 41.

    et al. Integrated genomic and gene expression profiling identifies two major genomic circuits in urothelial carcinoma. PLoS ONE 7, e38863 (2012).

  42. 42.

    et al. Copy number alterations in urothelial carcinomas: their clinicopathological significance and correlation with DNA methylation alterations. Carcinogenesis 32, 462–469 (2011).

  43. 43.

    , , & Novel tumor subgroups of urothelial carcinoma of the bladder defined by integrated genomic analysis. Clin. Cancer Res. 18, 5865–5877 (2012). This study uses a genomic approach to bladder tumour subclassification. It describes potential subclasses of the 'gold-standard' stage and grade groups based on DNA copy number and mutation.

  44. 44.

    et al. Focal amplifications are associated with high grade and recurrences in stage Ta bladder carcinoma. Int. J. Cancer 126, 1390–1402 (2010).

  45. 45.

    et al. Detailed analysis of focal chromosome arm 1q and 6p amplifications in urothelial carcinoma reveals complex genomic events on 1q, and as a possible auxiliary target on 6p. PLoS ONE 8, e67222 (2013).

  46. 46.

    , & Oncogenic FGFR3 gene fusions in bladder cancer. Hum. Mol. Genet. 22, 795–803 (2012). This study was the first to identify oncogenic FGFR3 fusions in bladder cancer. Importantly, cell lines with FGFR3 fusions were those previously reported to show high sensitivity to FGFR-targeted agents.

  47. 47.

    et al. Mutational context and diverse clonal development in early and late bladder cancer. Cell Rep. 7, 1649–1663 (2014).

  48. 48.

    et al. Mutational heterogeneity in cancer and the search for new cancer-associated genes. Nature 499, 214–218 (2013).

  49. 49.

    et al. An APOBEC cytidine deaminase mutagenesis pattern is widespread in human cancers. Nature Genet. 45, 970–976 (2013).

  50. 50.

    , & Evidence for APOBEC3B mutagenesis in multiple human cancers. Nature Genet. 45, 977–983 (2013).

  51. 51.

    et al. Frequent activating mutations of FGFR3 in human bladder and cervix carcinomas. Nature Genet. 23, 18–20 (1999). This study was the first to describe FGFR3 mutations in bladder cancer.

  52. 52.

    et al. Role of activating fibroblast growth factor receptor 3 mutations in the development of bladder tumors. Clin. Cancer Res. 11, 7709–7719 (2005).

  53. 53.

    et al. Prospective study of FGFR3 mutations as a prognostic factor in nonmuscle invasive urothelial bladder carcinomas. J. Clin. Oncol. 24, 3664–3671 (2006).

  54. 54.

    et al. The development of multiple bladder tumour recurrences in relation to the FGFR3 mutation status of the primary tumour. J. Pathol. 218, 104–112 (2009).

  55. 55.

    et al. Strong immunohistochemical expression of fibroblast growth factor receptor 3, superficial staining pattern of cytokeratin 20, and low proliferative activity define those papillary urothelial neoplasms of low malignant potential that do not recur. Cancer 112, 636–644 (2008).

  56. 56.

    et al. Prediction of progression of non-muscle-invasive bladder cancer by WHO 1973 and 2004 grading and by FGFR3 mutation status: a prospective study. Eur. Urol. 54, 835–844 (2007).

  57. 57.

    et al. The FGFR3 mutation is related to favorable pT1 bladder cancer. J. Urol. 187, 310–314 (2012).

  58. 58.

    et al. Frequent FGFR3 mutations in papillary non-invasive bladder (pTa) tumors. Am. J. Pathol. 158, 1955–1959 (2001).

  59. 59.

    et al. The incidence of thanatophoric dysplasia mutations in FGFR3 gene is higher in low-grade or superficial bladder carcinomas. Cancer 92, 2555–2561 (2001).

  60. 60.

    , , & FGFR3 protein expression and its relationship to mutation status and prognostic variables in bladder cancer. J. Pathol. 213, 91–98 (2007).

  61. 61.

    , L', , & Mutant fibroblast growth factor receptor 3 induces intracellular signaling and cellular transformation in a cell type- and mutation-specific manner. Oncogene 28, 4306–4316 (2009).

  62. 62.

    et al. A sequence variant at 4p16.3 confers susceptibility to urinary bladder cancer. Nature Genet. 42, 425–419 (2010).

  63. 63.

    , , , & Alternative splicing of fibroblast growth factor receptor 3 produces a secreted isoform that inhibits fibroblast growth factor-induced proliferation and is repressed in urothelial carcinoma cell lines. Cancer Res. 65, 10441–10449 (2005).

  64. 64.

    et al. Receptor specificity of the fibroblast growth factor family. The complete mammalian FGF family. J. Biol. Chem. 281, 15694–15700 (2006).

  65. 65.

    et al. Distinct microRNA alterations characterize high- and low-grade bladder cancer. Cancer Res. 69, 8472–8481 (2009). This study describes widespread alterations in microRNA expression in bladder cancer. A particularly interesting finding in low-grade tumours is loss of miR-99a and miR-100, which leads to upregulation of FGFR3.

  66. 66.

    , , & Fibroblast growth factor receptor 1 promotes proliferation and survival via activation of the mitogen-activated protein kinase pathway in bladder cancer. Cancer Res. 69, 4613–4620 (2009).

  67. 67.

    & Altered splicing of FGFR1 is associated with high tumor grade and stage and leads to increased sensitivity to FGF1 in bladder cancer. Am. J. Pathol. 177, 2379–2386 (2010).

  68. 68.

    , , , & FGFR1-induced epithelial to mesenchymal transition through MAPK/PLCγ/COX-2-mediated mechanisms. PLoS ONE 7, e38972 (2012).

  69. 69.

    et al. Fibroblast growth factor receptors-1 and -3 play distinct roles in the regulation of bladder cancer growth and metastasis: implications for therapeutic targeting. PLoS ONE 8, e57284 (2013).

  70. 70.

    et al. Distinctive expression pattern of ErbB family receptors signifies an aggressive variant of bladder cancer. J. Urol. 179, 353–358 (2008).

  71. 71.

    et al. Her-2/neu overexpression in muscle-invasive urothelial carcinoma of the bladder: prognostic significance and comparative analysis in primary and metastatic tumors. Clin. Cancer Res. 7, 2440–2447 (2001).

  72. 72.

    et al. HER2 overexpression in muscle-invasive urothelial carcinoma of the bladder: prognostic implications. Int. J. Cancer 102, 514–518 (2002).

  73. 73.

    , , & Expression of NRG1 and its receptors in human bladder cancer. Br. J. Cancer 104, 1135–1143 (2011).

  74. 74.

    , , , & Her2 amplification is significantly more frequent in lymph node metastases from urothelial bladder cancer than in the primary tumours. Eur. Urol. 60, 350–357 (2011).

  75. 75.

    et al. Co-expression of RON and MET is a prognostic indicator for patients with transitional-cell carcinoma of the bladder. Br. J. Cancer 92, 1906–1914 (2005).

  76. 76.

    et al. Overexpression of c-met as a prognostic indicator for transitional cell carcinoma of the urinary bladder: a comparison with p53 nuclear accumulation. J. Clin. Oncol. 20, 1544–1550 (2002).

  77. 77.

    , , , & Profiling bladder cancer using targeted antibody arrays. Am. J. Pathol. 168, 93–103 (2006).

  78. 78.

    et al. Mutations in FGFR3 and PIK3CA, singly or combined with RAS and AKT1, are associated with AKT but not with MAPK pathway activation in urothelial bladder cancer. Hum. Pathol. 43, 1573–1582 (2012).

  79. 79.

    et al. PIK3CA mutations are an early genetic alteration associated with FGFR3 mutations in superficial papillary bladder tumors. Cancer Res. 66, 7401–7404 (2006).

  80. 80.

    et al. FGFR3, HRAS, KRAS, NRAS and PIK3CA mutations in bladder cancer and their potential as biomarkers for surveillance and therapy. PLoS ONE 5, e13821 (2010).

  81. 81.

    & Helical domain and kinase domain mutations in p110α of phosphatidylinositol 3-kinase induce gain of function by different mechanisms. Proc. Natl Acad. Sci. USA 105, 2652–2657 (2008).

  82. 82.

    , & PIK3CA mutation spectrum in urothelial carcinoma reflects cell context-dependent signaling and phenotypic outputs. Oncogene 32, 768–776 (2012).

  83. 83.

    , , & Somatic mutation of PTEN in bladder carcinoma. Br. J. Cancer 80, 904–908 (1999).

  84. 84.

    , , , & Frequent loss of heterozygosity on chromosome 10q in muscle-invasive. Oncogene 14, 3059–3066 (1997).

  85. 85.

    et al. Cluster of allele losses within a 2.5 cM region of chromosome 10 in high-grade invasive bladder cancer. Oncogene 16, 909–913 (1998).

  86. 86.

    et al. Inactivation of p53 and Pten promotes invasive bladder cancer. Genes Dev. 23, 675–680 (2009).

  87. 87.

    et al. PTEN can inhibit in vitro organotypic and in vivo orthotopic invasion of human bladder cancer cells even in the absence of its lipid phosphatase activity. Oncogene 23, 6788–6797 (2004).

  88. 88.

    et al. FGFR3 and Ras gene mutations are mutually exclusive genetic events in urothelial cell carcinoma. Oncogene 24, 5218–5225 (2005).

  89. 89.

    et al. Activation of extracellular regulated kinases (ERK1/2) predicts poor prognosis in urothelial bladder carcinoma and is not associated with B-Raf gene mutations. Pathol. 41, 327–334 (2009).

  90. 90.

    et al. Activities of MAP-kinase pathways in normal uroepithelial cells and urothelial carcinoma cell lines. Exp. Cell Res. 282, 48–57 (2003).

  91. 91.

    et al. Somatic mutations of adenomatous polyposis coli gene and nuclear β-catenin accumulation have prognostic significance in invasive urothelial carcinomas: evidence for Wnt pathway implication. Int. J. Cancer 124, 103–108 (2009).

  92. 92.

    , , , & Aberrant expression of β-catenin and mutation of exon 3 of the β-catenin gene in renal and urothelial carcinomas. Pathol. Int. 50, 945–952 (2000).

  93. 93.

    et al. The prognostic value of E-cadherin, α-, β- and γ-catenin in bladder cancer patients who underwent radical cystectomy. Int. J. Urol. 14, 789–794 (2007).

  94. 94.

    et al. Identification and prognostic significance of an epithelial-mesenchymal transition expression profile in human bladder tumors. Clin. Cancer Res. 13, 1685–1694 (2007).

  95. 95.

    et al. Epigenetic inactivation of SFRP genes and TP53 alteration act jointly as markers of invasive bladder cancer. Cancer Res. 65, 7081–7085 (2005).

  96. 96.

    et al. Epigenetic inactivation of Wnt inhibitory factor-1 plays an important role in bladder cancer through aberrant canonical Wnt/β-catenin signaling pathway. Clin. Cancer Res. 12, 383–391 (2006).

  97. 97.

    et al. β-catenin activation synergizes with PTEN loss to cause bladder cancer formation. Oncogene 30, 178–189 (2011).

  98. 98.

    et al. Constitutive β-catenin activation induces male-specific tumorigenesis in the bladder urothelium. Cancer Res. 73, 5914–5925 (2013).

  99. 99.

    et al. Ras mutation cooperates with β-catenin activation to drive bladder tumourigenesis. Cell Death Dis. 2, e124 (2011).

  100. 100.

    et al. Hedgehog/Wnt feedback supports regenerative proliferation of epithelial stem cells in bladder. Nature 472, 110–114 (2011).

  101. 101.

    et al. Cellular origin of bladder neoplasia and tissue dynamics of its progression to invasive carcinoma. Nature Cell Biol. 16, 469–478 (2014).

  102. 102.

    et al. Hedgehog signaling restrains bladder cancer progression by eliciting stromal production of urothelial differentiation factors. Cancer Cell 26, 521–533 (2014). Using the BBN-induced invasive bladder cancer mouse model, this study provides evidence for a tumour suppressor role for hedgehog signalling from urothelium to stroma that in turn influences urothelial cell differentiation. BMP4 and BMP5 were among the SHH-induced stromal factors that stimulated urothelial differentiation. Importantly, pharmacological activation of the BMP pathway was shown to block tumour progression in this system.

  103. 103.

    , , , & Hedgehog signaling in normal urothelial cells and in urothelial carcinoma cell lines. J. Cell. Physiol. 203, 372–377 (2005).

  104. 104.

    , & Prognostic value of cell-cycle regulation biomarkers in bladder cancer. Semin. Oncol. 39, 524–533 (2012).

  105. 105.

    , , , & Inactivation of the Rb pathway and overexpression of both isoforms of E2F3 are obligate events in bladder tumours with 6p22 amplification. Oncogene 27, 2716–2727 (2008).

  106. 106.

    , , & Amplification at chromosome 11q13 in transitional cell tumours of the bladder. Oncogene 6, 789–795 (1991).

  107. 107.

    et al. Prognostic factors in survival of patients with stage Ta and T1 bladder urothelial tumors: the role of G1–S modulators (p53, 21Waf1, 27Kip1, cyclin D1, and cyclin D3), proliferation index, and clinicopathologic parameters. Am. J. Clin. Pathol. 122, 444–452 (2004).

  108. 108.

    & Epigenetic biomarkers in urothelial bladder cancer. Expert Rev. Mol. Diagn. 9, 259–269 (2009).

  109. 109.

    , & Global epigenetic profiling in bladder cancer. Epigenomics 3, 35–45 (2011).

  110. 110.

    Hypermethylation in bladder cancer: biological pathways and translational applications. Tumour Biol. 33, 347–361 (2012). This is a comprehensive review of the extensive literature on DNA hypermethylation in bladder cancer.

  111. 111.

    & Epigenetics of kidney cancer and bladder cancer. Epigenomics 3, 19–34 (2011).

  112. 112.

    et al. Genome-wide analysis of CpG island methylation in bladder cancer identified TBX2, TBX3, GATA2, and ZIC4 as pTa-specific prognostic markers. Eur. Urol. 61, 1245–1256 (2012).

  113. 113.

    et al. Identification of methylated genes associated with aggressive bladder cancer. PLoS ONE 5, e12334 (2010).

  114. 114.

    et al. Comprehensive genome methylation analysis in bladder cancer: identification and validation of novel methylated genes and application of these as urinary tumor markers. Clin. Cancer Res. 17, 5582–5592 (2011).

  115. 115.

    et al. Unique DNA methylation patterns distinguish noninvasive and invasive urothelial cancers and establish an epigenetic field defect in premalignant tissue. Cancer Res. 70, 8169–8178 (2010). This genome-wide methylation study of normal urothelium and tumours of all grades and stages found distinct patterns of hypomethylation in NMIBCs and widespread promoter hypermethylation in invasive tumours.

  116. 116.

    et al. DNA methylation analyses of urothelial carcinoma reveal distinct epigenetic subtypes and an association between gene copy number and methylation status. Epigenetics 7, 858–867 (2012).

  117. 117.

    et al. Decoding the regulatory landscape of medulloblastoma using DNA methylation sequencing. Nature 510, 537–541 (2014).

  118. 118.

    , , , & Integrated epigenome profiling of repressive histone modifications, DNA methylation and gene expression in normal and malignant urothelial cells. PLoS ONE 7, e32750 (2012).

  119. 119.

    et al. A novel epigenetic phenotype associated with the most aggressive pathway of bladder tumor progression. J. Natl Cancer Inst. 103, 47–60 (2011).

  120. 120.

    et al. Detection of urothelial bladder cancer cells in voided urine can be improved by a combination of cytology and standardized microsatellite analysis. Cancer Epidemiol. Biomarkers Prev. 18, 1798–1806 (2009).

  121. 121.

    et al. Combinations of urinary biomarkers for surveillance of patients with incident nonmuscle invasive bladder cancer: the European FP7 UROMOL project. J. Urol. 189, 1945–1951 (2012). This study assesses combinations of urine biomarkers for detection and surveillance of bladder cancer in a large group of patients.

  122. 122.

    et al. Optimization of nonmuscle invasive bladder cancer recurrence detection using a urine based FGFR3 mutation assay. J. Urol. 186, 707–712 (2011).

  123. 123.

    et al. Detection of bladder cancer using novel DNA methylation biomarkers in urine sediments. Cancer Epidemiol. Biomarkers Prev. 20, 1483–1491 (2011).

  124. 124.

    et al. A methylation assay for the detection of non-muscle-invasive bladder cancer (NMIBC) recurrences in voided urine. BJU Int. 109, 941–948 (2012).

  125. 125.

    et al. Identification and validation of the methylated TWIST1 and NID2 genes through real-time methylation-specific polymerase chain reaction assays for the noninvasive detection of primary bladder cancer in urine samples. Eur. Urol. 58, 96–104 (2010).

  126. 126.

    et al. A 3-plex methylation assay combined with the FGFR3 mutation assay sensitively detects recurrent bladder cancer in voided urine. Clin. Cancer Res. 19, 4760–4769 (2013).

  127. 127.

    et al. Telomerase reverse transcriptase promoter mutations in bladder cancer: high frequency across stages, detection in urine, and lack of association with outcome. Eur. Urol. 65, 360–366 (2013). This study identifies TERT promoter mutations at high frequency in bladder tumours of all grades and stages, and reports their use as a urine biomarker. These mutations are the most common event identified in bladder cancer so far.

  128. 128.

    , & Comprehensive mutation analysis of the TERT promoter in bladder cancer and detection of mutations in voided urine. Eur. Urol. 65, 367–369 (2013).

  129. 129.

    The uroepithelium: not just a passive barrier. Traffic 5, 117–128 (2004).

  130. 130.

    et al. The human urothelium consists of multiple clonal units, each maintained by a stem cell. J. Pathol. 225, 163–171 (2011).

  131. 131.

    , & Normal and neoplastic urothelial stem cells: getting to the root of the problem. Nature Rev. Urol. 9, 583–594 (2012).

  132. 132.

    , & Epithelial plasticity, cancer stem cells, and the tumor-supportive stroma in bladder carcinoma. Mol. Cancer Res. 10, 995–1009 (2012).

  133. 133.

    et al. Differentiation of a highly tumorigenic basal cell compartment in urothelial carcinoma. Stem Cells 27, 1487–1495 (2009).

  134. 134.

    et al. Identification, molecular characterization, clinical prognosis, and therapeutic targeting of human bladder tumor-initiating cells. Proc. Natl Acad. Sci. USA 106, 14016–14021 (2009).

  135. 135.

    et al. Blocking PGE2-induced tumor repopulation abrogates bladder cancer chemoresistance. Nature (2014).

  136. 136.

    et al. Three differentiation states risk-stratify bladder cancer into distinct subtypes. Proc. Natl Acad. Sci. USA 109, 2078–2083 (2012). This study identifies tumour-initiating cells from bladder tumours of different grades and stages. A key finding is that tumour-initiating cells from aggressive tumours showed a basal phenotype, whereas those from non-invasive tumours had features of more differentiated cells, suggesting a non-basal derivation.

  137. 137.

    et al. Bladder cancers arise from distinct urothelial sub-populations. Nature Cell Biol. 16, 982–991 (2014).

  138. 138.

    et al. Analysis of genetic alterations in normal bladder urothelium. Urology 62, 1134–1138 (2003).

  139. 139.

    et al. Fluorescence in situ hybridization detects frequent chromosome 9 deletions and aneuploidy in histologically normal urothelium of bladder cancer patients. Oncol. Rep. 11, 745–751 (2004).

  140. 140.

    et al. Papillary urothelial hyperplasia is a clonal precursor to papillary transitional cell bladder cancer. Int. J. Cancer 89, 514–518 (2000).

  141. 141.

    et al. Frequent genetic alterations in simple urothelial hyperplasias of the bladder in patients with papillary urothelial carcinoma. Am. J. Pathol. 154, 721–727 (1999).

  142. 142.

    et al. Chromosome 9 deletions are more frequent than FGFR3 mutations in flat urothelial hyperplasias of the bladder. Int. J. Cancer 119, 1212–1215 (2006).

  143. 143.

    et al. Occurrence of chromosome 9 and p53 alterations in multifocal dysplasia and carcinoma in situ of human urinary bladder. Cancer Res. 62, 809–818 (2002).

  144. 144.

    3rd. et al. Two molecular pathways to transitional cell carcinoma of the bladder. Cancer Res. 54, 784–788 (1994).

  145. 145.

    et al. Identification of chromosome 9 alterations and p53 accumulation in isolated carcinoma in situ of the urinary bladder versus carcinoma in situ associated with carcinoma. Am. J. Pathol. 161, 1119–1125 (2002).

  146. 146.

    , , , & Partial allelotype of carcinoma in situ of the human bladder. Cancer Res. 55, 5213–5216 (1995).

  147. 147.

    , , , & Consistent genomic alterations in carcinoma in situ of the urinary bladder confirm the presence of two major pathways in bladder cancer development. Int. J. Cancer 125, 2095–2103 (2009).

  148. 148.

    et al. Genetic modeling of human urinary bladder carcinogenesis. Genes Chromosomes Cancer 27, 392–402 (2000).

  149. 149.

    et al. Status of the p53, p16, RB1, and HER-2 genes and chromosomes 3, 7, 9, and 17 in advanced bladder cancer: correlation with adjacent mucosa and pathological parameters. J. Clin. Pathol. 58, 367–371 (2005).

  150. 150.

    et al. Forerunner genes contiguous to RB1 contribute to the development of in situ neoplasia. Proc. Natl Acad. Sci. USA 104, 13732–13737 (2007).

  151. 151.

    et al. Histologic-genetic mapping by allele-specific PCR reveals intraurothelial spread of p53 mutant tumor clones. Lab Invest. 82, 1553–1561 (2002).

  152. 152.

    et al. Understanding the development of human bladder cancer by using a whole-organ genomic mapping strategy. Lab Invest. 88, 694–721 (2008).

  153. 153.

    et al. Evidence for oligoclonality and tumor spread by intraluminal seeding in multifocal urothelial carcinomas of the upper and lower urinary tract. Oncogene 20, 4910–4915 (2001).

  154. 154.

    et al. Precise microdissection of human bladder carcinomas reveals divergent tumor subclones in the same tumor. Cancer 94, 104–110 (2002).

  155. 155.

    Origin of multifocal carcinomas of the bladder and upper urinary tract: molecular analysis and clinical implications. Int. J. Urol. 12, 709–716 (2005).

  156. 156.

    et al. Clonal and chronological genetic analysis of multifocal cancers of the bladder and upper urinary tract. Cancer Res. 58, 5835–5841 (1998).

  157. 157.

    et al. High throughput comparative genomic hybridization array analysis of multifocal urothelial cancers. Cancer Sci. 97, 746–752 (2006).

  158. 158.

    et al. Genetic analysis of multifocal superficial urothelial cancers by array-based comparative genomic hybridisation. Br. J. Cancer 97, 260–266 (2007).

  159. 159.

    et al. Molecular evolution of multiple recurrent cancers of the bladder. Hum. Mol. Genet. 9, 2973–2980 (2000).

  160. 160.

    , , , & Analysis of the copy number profiles of several tumor samples from the same patient reveals the successive steps in tumorigenesis. Genome Biol. 11, R76 (2010).

  161. 161.

    et al. Grade progression and regression in recurrent urothelial cancer. J. Urol. 169, 2106–2109 (2003).

  162. 162.

    , , & Regulation of epithelial–mesenchymal and mesenchymal–epithelial transitions by microRNAs. Curr. Opin. Cell Biol. 25, 200–207 (2013).

  163. 163.

    et al. Coordinated epigenetic repression of the miR-200 family and miR-205 in invasive bladder cancer. Int. J. Cancer 128, 1327–1334 (2011).

  164. 164.

    et al. miR-200 expression regulates epithelial-to-mesenchymal transition in bladder cancer cells and reverses resistance to epidermal growth factor receptor therapy. Clin. Cancer Res. 15, 5060–5072 (2009).

  165. 165.

    et al. Relationship between E-cadherin and fibroblast growth factor receptor 2b expression in bladder carcinomas. Oncogene 18, 5722–5726 (1999).

  166. 166.

    et al. Mesenchymal-to-epithelial transition facilitates bladder cancer metastasis: role of fibroblast growth factor receptor-2. Cancer Res. 66, 11271–11278 (2006).

  167. 167.

    et al. A novel role of Id-1 in regulation of epithelial-to-mesenchymal transition in bladder cancer. Urol. Oncol. 31, 1242–1253 (2012).

  168. 168.

    et al. Long non-coding RNA H19 increases bladder cancer metastasis by associating with EZH2 and inhibiting E-cadherin expression. Cancer Lett. 333, 213–221 (2013).

  169. 169.

    et al. TGF-β -induced upregulation of malat1 promotes bladder cancer metastasis by associating with suz12. Clin. Cancer Res. 20, 1531–1541 (2014).

  170. 170.

    et al. Distinct expression profiles of p63 variants during urothelial development and bladder cancer progression. Am. J. Pathol. 178, 1350–1360 (2011).

  171. 171.

    et al. The p63 protein isoform ΔNp63α inhibits epithelial-mesenchymal transition in human bladder cancer cells: role of miR-205. J. Biol. Chem. 288, 3275–3288 (2013).

  172. 172.

    et al. p63 expression defines a lethal subset of muscle-invasive bladder cancers. PLoS ONE 7, e30206 (2012).

  173. 173.

    et al. Intrinsic subtypes of high-grade bladder cancer reflect the hallmarks of breast cancer biology. Proc. Natl Acad. Sci. USA 111, 3110–3115 (2014). This is one of three recent gene expression profiling studies of MIBC that define major basal and luminal expression subtypes. (See also references 37 and 194).

  174. 174.

    & The faces and friends of RhoGDI2. Cancer Metastasis Rev. 31, 519–528 (2012).

  175. 175.

    et al. Src phosphorylation of RhoGDI2 regulates its metastasis suppressor function. Proc. Natl Acad. Sci. 106, 5807–5812 (2009).

  176. 176.

    et al. Elevated expression of pp60c–src in low grade human bladder carcinoma. Cancer Res. 52, 1457–1462 (1992).

  177. 177.

    et al. The interrelationships between Src, Cav-1 and RhoGD12 in transitional cell carcinoma of the bladder. Br. J. Cancer 106, 1187–1195 (2012).

  178. 178.

    , , & RhoGDI2 suppresses lung metastasis in mice by reducing tumor versican expression and macrophage infiltration. J. Clin. Invest. 122, 1503–1518 (2012).

  179. 179.

    & RhoGDI2 suppresses bladder cancer metastasis via reduction of inflammation in the tumor microenvironment. Oncoimmunology 1, 1175–1177 (2012).

  180. 180.

    , , , & Loss of SPARC in bladder cancer enhances carcinogenesis and progression. J. Clin. Invest. 123, 751–766 (2013).

  181. 181.

    et al. ATF3 suppresses metastasis of bladder cancer by regulating gelsolin-mediated remodeling of the actin cytoskeleton. Cancer Res. 73, 3625–3637 (2013).

  182. 182.

    & The Ral GTPase pathway in metastatic bladder cancer: key mediator and therapeutic target. Urol. Oncol. 27, 42–47 (2009).

  183. 183.

    et al. Downregulation of Ral GTPase-activating protein promotes tumor invasion and metastasis of bladder cancer. Oncogene 32, 894–902 (2013).

  184. 184.

    et al. CD24 offers a therapeutic target for control of bladder cancer metastasis based on a requirement for lung colonization. Cancer Res. 71, 3802–3811 (2011).

  185. 185.

    et al. CD24 expression is important in male urothelial tumorigenesis and metastasis in mice and is androgen regulated. Proc. Natl Acad. Sci. USA 109, E3588–E3596 (2012).

  186. 186.

    et al. Bladder cancer outcome and subtype classification by gene expression. Clin. Cancer Res. 11, 4044–4055 (2005).

  187. 187.

    et al. Analysis of molecular intra-patient variation and delineation of a prognostic 12-gene signature in non-muscle invasive bladder cancer; technology transfer from microarrays to PCR. Br. J. Cancer 107, 1392–1398 (2012).

  188. 188.

    et al. Identifying distinct classes of bladder carcinoma using microarrays. Nature Genet. 33, 90–96 (2003).

  189. 189.

    et al. Gene expression signatures predict outcome in non-muscle-invasive bladder carcinoma: a multicenter validation study. Clin. Cancer Res. 13, 3545–3551 (2007).

  190. 190.

    , , , & Defining molecular profiles of poor outcome in patients with invasive bladder cancer using oligonucleotide microarrays. J. Clin. Oncol. 24, 778–789 (2006).

  191. 191.

    et al. Predictive value of progression-related gene classifier in primary non-muscle invasive bladder cancer. Mol. Cancer 9, 3 (2010).

  192. 192.

    et al. A molecular taxonomy for urothelial carcinoma. Clin. Cancer Res. 18, 3377–3386 (2012). This study was the first to describe a molecular taxonomy for bladder cancer based on gene expression profiling of tumours of all stages and grades. Molecular subtypes traversing pathological classification and with distinct clinical outcomes are reported.

  193. 193.

    et al. Toward a molecular pathologic classification of urothelial carcinoma. Am. J. Pathol. 183, 681–691 (2013).

  194. 194.

    et al. Identification of distinct basal and luminal subtypes of muscle-invasive bladder cancer with different sensitivities to frontline chemotherapy. Cancer Cell 25, 152–165 (2014). This is one of three recent gene expression profiling studies of MIBC that define major basal and luminal expression subtypes. See also references 37 and 173. This study defines two luminal subtypes, one of which contains tumours that show resistance to cisplatin-based therapy.

  195. 195.

    et al. Intrinsic basal and luminal subtypes of muscle-invasive bladder cancer. Nature Rev. Urol. 11, 400–410 (2014). This is a useful review of recent expression profiling studies that identifies overlap of clusters defined by different groups and highlights specific features of the subtypes defined.

  196. 196.

    et al. Multiplatform analysis of 12 cancer types reveals molecular classification within and across tissues of origin. Cell 158, 929–944 (2014). This excellent pan-cancer study includes data on MIBC from a TCGA study and shows alignment of bladder tumours with squamous features with aggressive breast and ovarian cancers.

  197. 197.

    , , & Re: , , Dinney. New insights into subtypes of invasive bladder cancer: considerations of the clinician. Eur. Urol. (2014).

  198. 198.

    , & Reply to Mattias Aine, Fredrik Liedberg, Gottfrid Sjodahl & Mattias Hoglund's Letter to the Editor re: David, J. McConkey, Woonyoung Choi, Colin, P. N. Dinney. New insights into subtypes of invasive bladder cancer: considerations of the clinician. Eur. Urol. (2014).

  199. 199.

    et al. EGFR as a potential therapeutic target for a subset of muscle-invasive bladder cancers presenting a basal-like phenotype. Sci. Transl Med. 6, 244ra291 (2014).

  200. 200.

    et al. DNA methylation profiles delineate etiologic heterogeneity and clinically important subgroups of bladder cancer. Carcinogenesis 31, 1972–1976 (2010).

  201. 201.

    et al. Combined gene expression and genomic profiling define two intrinsic molecular subtypes of urothelial carcinoma and gene signatures for molecular grading and outcome. Cancer Res. 70, 3463–3472 (2010).

Download references


The authors thank Cancer Research UK (C6228/A5433; C6228/A12512; C37059/A11941) and Yorkshire Cancer Research (L346, L362, L367, L372, L376PA) for past and current funding of their work. They also thank M. Höglund and K. S. Chan for discussions during the writing of this Review.

Author information


  1. Section of Experimental Oncology, Leeds Institute of Cancer and Pathology, St James's University Hospital, Beckett Street, Leeds, LS9 7TF, UK.

    • Margaret A. Knowles
    •  & Carolyn D. Hurst


  1. Search for Margaret A. Knowles in:

  2. Search for Carolyn D. Hurst in:

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to Margaret A. Knowles.


Tumour–Node–Metastasis system

(TNM system). A classification system used to describe the stage of a tumour. T describes the extent of local invasion; N describes whether the tumour has spread to local lymph nodes; and M describes distant metastatic spread.


Chromosomal shattering. A phenomenon whereby cancer cells acquire many clustered chromosomal rearrangements as a single catastrophic event during tumour development.

Non-homologous end-joining

An error-prone mechanism of DNA repair in which broken DNA ends are joined without the guidance of a large homologous template. Short homologous DNA sequences termed microhomologies are used to guide repair.

Replication-licensing complex

A complex of proteins that assemble at origins of DNA replication during late G1 phase of the cell cycle to ensure precise and timely DNA replication.

Homologous recombination

A high-fidelity mechanism of DNA repair that uses recombination with an intact homologous template to repair double-strand breaks.

Bacillus Calmette–Guerin

(BCG). A vaccine used to induce immunity to tuberculosis. It is also used to treat high-risk localized bladder cancer and carcinoma in situ. Instillation of BCG into the bladder induces a localized immune response that is able to eliminate cancer cells. For bladder cancer treatment, a course of 6 weekly treatments is usual.

Smoking pack-years

A measure of exposure to cigarette smoke that is calculated by multiplying the number of packs of cigarettes smoked per day by the number of years the person has smoked. For example, 1 pack-year is equal to smoking 20 cigarettes (1 pack) per day for 1 year or 40 cigarettes per day for half a year.


Less densely packed or 'open' chromatin that is often associated with active transcription.

Field change

A process by which molecular alterations are accumulated within a large tissue area in response to carcinogenic stimuli.

About this article

Publication history



Further reading