Most epithelial tissues contain self-renewing stem cells that mature into downstream progenies with increasingly limited differentiation potential. It is not surprising that cancers arising from such hierarchically organized epithelial tissues retain features of cellular differentiation. Accumulating evidence suggests that the urothelium of the urinary bladder is a hierarchically organized tissue, containing tissue-specific stem cells that are important for both normal homeostasis and injury response. The phenotypic and functional properties of cancer stem cells (CSCs; also known as tumour-initiating cells) from bladder cancer tissue have been studied in detail. Urothelial CSCs are not isolated by a 'one-marker-fits-all' approach; instead, various cell surface marker combinations (possibly reflecting the cell-of-origin) are used to isolate CSCs from distinct differentiation subtypes of urothelial carcinomas. Additional CSC markers, including cytokeratin 14 (CK14), aldehyde dehydrogenase 1 family, member A1 (ALDH1A1), and tumour protein 63 (p63), have revealed prognostic value for urothelial carcinomas. Signalling pathways involved in normal stem cell self-renewal and differentiation are implicated in the malignant transformation of different subsets of urothelial carcinomas. Early expansion of primitive CK14+ cells—driven by genetic pathways such as STAT3—can lead to the development of carcinoma in situ, and CSC-enriched urothelial carcinomas are associated with poor clinical outcomes. Given that bladder CSCs are the proposed root of malignancy and drivers of cancer initiation and progression for urothelial carcinomas, these cells are ideal targets for anticancer therapies.
Normal slow-cycling urothelium demonstrates rapid regenerative potential and the ability to transdifferentiate into multiple cell types; characteristics that support the existence of normal urothelial stem cells
Evidence suggests that urothelial stem cells primarily originate from basal cells, whereas an alternative pool of stem cells might exist that could give rise to umbrella cells within the urothelium
Tumorigenic subpopulations of cancer stem cells (CSCs) with basal cell characteristics and phenotypic markers are evident in primary bladder cancers, xenografts, and immortalized cell lines
Signalling pathways implicated in normal stem cell self-renewal and lineage differentiation have major roles in bladder cancer development; heterogeneity in their activation status is evident among patients
Bladder cancers can be categorized into subtypes on the basis of differentiation status; the most primitive basal subtypes and cell markers correlate with poor clinical outcomes
Novel targeted approaches for treating bladder CSCs might improve the efficacy of current standard-of-care treatment regimens when administered as combination therapy
This is a preview of subscription content
Subscribe to Journal
Get full journal access for 1 year
only $4.92 per issue
All prices are NET prices.
VAT will be added later in the checkout.
Tax calculation will be finalised during checkout.
Get time limited or full article access on ReadCube.
All prices are NET prices.
Wagers, A. J. & Weissman, I. L. Plasticity of adult stem cells. Cell 116, 639–648 (2004).
Blair, K., Wray, J. & Smith, A. The liberation of embryonic stem cells. PLoS Genet. 7, e1002019 (2011).
Takahashi, K. & Yamanaka, S. Induction of pluripotent stem cells from mouse embryonic and adult fibroblast cultures by defined factors. Cell 126, 663–676 (2006).
Weissman, I. L. Stem cells: units of development, units of regeneration, and units in evolution. Cell 100, 157–168 (2000).
Watt, F. M., Lo Celso, C. & Silva-Vargas, V. Epidermal stem cells: an update. Curr. Opin. Genet. Dev. 16, 518–524 (2006).
Majo, F., Rochat, A., Nicolas, M., Jaoude, G. A. & Barrandon, Y. Oligopotent stem cells are distributed throughout the mammalian ocular surface. Nature 456, 250–254 (2008).
Bonnet, D. & Dick, J. E. Human acute myeloid leukemia is organized as a hierarchy that originates from a primitive hematopoietic cell. Nature medicine 3, 730–737 (1997).
Al-Hajj, M., Wicha, M. S., Benito-Hernandez, A., Morrison, S. J. & Clarke, M. F. Prospective identification of tumorigenic breast cancer cells. Proc. Natl Acad. Sci. USA 100, 3983–3988 (2003).
Singh, S. K. et al. Identification of human brain tumour initiating cells. Nature 432, 396–401 (2004).
Dalerba, P. et al. Phenotypic characterization of human colorectal cancer stem cells. Proc. Natl Acad. Sci. USA 104, 10158–10163 (2007).
Herzenberg, L. A. & Sweet, R. G. Fluorescence-activated cell sorting. Sci. Am. 234, 108–117 (1976).
Spangrude, G. J., Heimfeld, S. & Weissman, I. L. Purification and characterization of mouse hematopoietic stem cells. Science 241, 58–62 (1988).
Smith, L. G., Weissman, I. L. & Heimfeld, S. Clonal analysis of hematopoietic stem-cell differentiation in vivo. Proc. Natl Acad. Sci. USA 88, 2788–2792 (1991).
Baum, C. M., Weissman, I. L., Tsukamoto, A. S., Buckle, A. M. & Peault, B. Isolation of a candidate human hematopoietic stem-cell population. Proc. Natl Acad. Sci. USA 89, 2804–2808 (1992).
Shackleton, M. et al. Generation of a functional mammary gland from a single stem cell. Nature 439, 84–88 (2006).
Clarke, M. F. et al. Cancer stem cells—perspectives on current status and future directions: AACR Workshop on cancer stem cells. Cancer Res. 66, 9339–9344 (2006).
Pastrana, E., Silva-Vargas, V. & Doetsch, F. Eyes wide open: a critical review of sphere-formation as an assay for stem cells. Cell Stem Cell 8, 486–498 (2011).
Apodaca, G. The uroepithelium: not just a passive barrier. Traffic 5, 117–128 (2004).
Khandelwal, P., Abraham, S. N. & Apodaca, G. Cell biology and physiology of the uroepithelium. Am. J. Physiol. Renal Physiol. 297, F1477–F1501 (2009).
Romih, R. & Jezernik, K. Reorganisation of the urothelial luminal plasma membrane in the cyclophosphamide treated rats. Pflugers Arch. 431, R241–242 (1996).
Kreft, M. E., Sterle, M., Veranic, P. & Jezernik, K. Urothelial injuries and the early wound healing response: tight junctions and urothelial cytodifferentiation. Histochem. Cell Biol. 123, 529–539 (2005).
Lavelle, J. et al. Bladder permeability barrier: recovery from selective injury of surface epithelial cells. Am. J. Physiol. Renal Physiol. 283, F242–253 (2002).
Kvist, E., Sjolin, K. E., Laursen, H., Orntoft, T. F. & Sturmer, M. A. Squamous cell metaplasia of the bladder urothelium. A retrospective study of 36 patients. APMIS 100, 650–654 (1992).
Susmano, D., Rubenstein, A. B., Dakin, A. R. & Lloyd, F. A. Cystitis glandularis and adenocarcinoma of the bladder. J. Urol. 105, 671–674 (1971).
Potten, C. S. & Morris, R. J. Epithelial stem cells in vivo. J. Cell Sci. Suppl. 10, 45–62 (1988).
Bromberg, J. F. et al. Stat3 as an oncogene. Cell 98, 295–303 (1999).
Langkilde, N. C., Wolf, H. & Orntoft, T. F. DNA replication in experimental rat bladder tumours: immunohistochemical detection of bromodeoxyuridine labelled nuclei. Scand. J. Urol. Nephrol. Suppl. 125, 133–139 (1989).
Kurzrock, E. A., Lieu, D. K., Degraffenried, L. A., Chan, C. W. & Isseroff, R. R. Label-retaining cells of the bladder: candidate urothelial stem cells. Am. J. Physiol. Renal Physiol. 294, F1415–F1421 (2008).
Shin, K. et al. Hedgehog/Wnt feedback supports regenerative proliferation of epithelial stem cells in bladder. Nature 472, 110–114 (2011).
Gaisa, N. T. et al. The human urothelium consists of multiple clonal units, each maintained by a stem cell. J. Pathol. 225, 163–171 (2011).
Zhang, H. et al. Label retaining and stem cell marker expression in the developing rat urinary bladder. Urology 79, 746 e1–6 (2012).
Signoretti, S. et al. p63 regulates commitment to the prostate cell lineage. Proc. Natl Acad. Sci. USA 102, 11355–11360 (2005).
Karni-Schmidt, O. et al. Distinct expression profiles of p63 variants during urothelial development and bladder cancer progression. Am. J. Pathol. 178, 1350–1360 (2011).
Prasad, S. M., Decastro, G. J. & Steinberg, G. D. Urothelial carcinoma of the bladder: definition, treatment and future efforts. Nat. Rev. Urol. 8, 631–642 (2011).
Chan, K. S., Volkmer, J. P. & Weissman, I. Cancer stem cells in bladder cancer: a revisited and evolving concept. Curr. Opin. Urol. 20, 393–397 (2010).
Dotsikas, G. et al. Cellular heterogeneity in normal and neoplastic human urothelium: a study using murine monoclonal antibodies. Br. J. Cancer 56, 439–444 (1987).
Chan, K. S. 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).
Yang, Y. M. & Chang, J. W. Bladder cancer initiating cells (BCICs) are among EMA-CD44v6+ subset: novel methods for isolating undetermined cancer stem (initiating) cells. Cancer Invest. 26, 725–733 (2008).
Edris, B. et al. Antibody therapy targeting the CD47 protein is effective in a model of aggressive metastatic leiomyosarcoma. Proc. Natl Acad. Sci. USA 109, 6656–6661 (2012).
He, X. et al. Differentiation of a highly tumorigenic basal cell compartment in urothelial carcinoma. Stem Cells 27, 1487–1495 (2009).
Goodell, M. A., Brose, K., Paradis, G., Conner, A. S. & Mulligan, R. C. Isolation and functional properties of murine hematopoietic stem cells that are replicating in vivo. J. Exp. Med. 183, 1797–1806 (1996).
She, J. J., Zhang, P. G., Wang, Z. M., Gan, W. M. & Che, X. M. Identification of side population cells from bladder cancer cells by DyeCycle Violet staining. Cancer Biol. Ther. 7, 1663–1668 (2008).
Ning, Z. F. et al. Subpopulations of stem-like cells in side population cells from the human bladder transitional cell cancer cell line T24. J. Int. Med. Res. 37, 621–630 (2009).
Su, Y. et al. Aldehyde dehydrogenase 1 A1-positive cell population is enriched in tumor-initiating cells and associated with progression of bladder cancer. Cancer Epidemiol. Biomarkers Prev. 19, 327–337 (2010).
Kawakami, S. et al. PPAR-gamma ligands suppress proliferation of human urothelial basal cells in vitro. J. Cell Physiol. 191, 310–319 (2002).
Varley, C. L. et al. Role of PPAR-gamma and EGFR signalling in the urothelial terminal differentiation programme. J. Cell Sci. 117, 2029–2036 (2004).
Mylona, E. et al. Peroxisome proliferator-activated receptor gamma expression in urothelial carcinomas of the bladder: association with differentiation, proliferation and clinical outcome. Eur. J. Surg. Oncol. 35, 197–201 (2009).
Varley, C. L. & Southgate, J. Effects of PPAR agonists on proliferation and differentiation in human urothelium. Exp. Toxicol. Pathol. 60, 435–441 (2008).
de Boer, W. I., Rebel, J. M., Vermey, M., de Jong, A. A. & van der Kwast, T. H. Characterization of distinct functions for growth factors in murine transitional epithelial cells in primary organotypic culture. Exp. Cell Res. 214, 510–518 (1994).
Baskin, L. S. et al. Growth factors in bladder wound healing. J. Urol. 157, 2388–2395 (1997).
Daher, A. et al. Growth, differentiation and senescence of normal human urothelium in an organ-like culture. Eur. Urol. 45, 799–805 (2004).
Varley, C. et al. Autocrine regulation of human urothelial cell proliferation and migration during regenerative responses in vitro. Exp. Cell Res. 306, 216–229 (2005).
Ling, S. et al. An EGFR-ERK-SOX9 signaling cascade links urothelial development and regeneration to cancer. Cancer Res. 71, 3812–3821 (2011).
Mellon, K., Wright, C., Kelly, P., Horne, C. H. & Neal, D. E. Long-term outcome related to epidermal growth factor receptor status in bladder cancer. J. Urol. 153, 919–925 (1995).
Reya, T. et al. A role for Wnt signalling in self-renewal of haematopoietic stem cells. Nature 423, 409–414 (2003).
Park, I. K. et al. Bmi-1 is required for maintenance of adult self-renewing haematopoietic stem cells. Nature 423, 302–305 (2003).
Prince, M. E. et al. Identification of a subpopulation of cells with cancer stem cell properties in head and neck squamous cell carcinoma. Proc. Natl Acad. Sci. USA 104, 973–978 (2007).
Niwa, H., Burdon, T., Chambers, I. & Smith, A. Self-renewal of pluripotent embryonic stem cells is mediated via activation of STAT3. Genes Dev. 12, 2048–2060 (1998).
Bromberg, J. Stat proteins and oncogenesis. J. Clin. Invest. 109, 1139–1142 (2002).
Chan, K. S. et al. Disruption of Stat3 reveals a critical role in both the initiation and the promotion stages of epithelial carcinogenesis. J. Clin. Invest. 114, 720–728 (2004).
Chambers, I. et al. Functional expression cloning of Nanog, a pluripotency sustaining factor in embryonic stem cells. Cell 113, 643–655 (2003).
Hochedlinger, K., Yamada, Y., Beard, C. & Jaenisch, R. Ectopic expression of Oct-4 blocks progenitor-cell differentiation and causes dysplasia in epithelial tissues. Cell 121, 465–477 (2005).
Volkmer, J. P. et al. Three differentiation states risk-stratify bladder cancer into distinct subtypes. Proc. Natl Acad. Sci. USA 109, 2078–2083 (2012).
Urist, M. J. et al. Loss of p63 expression is associated with tumor progression in bladder cancer. Am. J. Pathol. 161, 1199–1206 (2002).
Koga, F. et al. Impaired p63 expression associates with poor prognosis and uroplakin III expression in invasive urothelial carcinoma of the bladder. Clin. Cancer Res. 9, 5501–5507 (2003).
Choi, W. et al. p63 expression defines a lethal subset of muscle-invasive bladder cancers. PLoS ONE 7, e30206 (2012).
Gaisa, N. T. et al. Different immunohistochemical and ultrastructural phenotypes of squamous differentiation in bladder cancer. Virchows Arch. 458, 301–312 (2011).
Samaratunga, H. & Khoo, K. Micropapillary variant of urothelial carcinoma of the urinary bladder; a clinicopathological and immunohistochemical study. Histopathology 45, 55–64 (2004).
Dyrskjot, L. et al. Gene expression in the urinary bladder: a common carcinoma in situ gene expression signature exists disregarding histopathological classification. Cancer Res. 64, 4040–4048 (2004).
Brosens, J. J. & Parker, M. G. Gene expression: oestrogen receptor hijacked. Nature 423, 487–488 (2003).
Sanchez-Carbayo, M., Socci, N. D., Lozano, J., Saint, F. & Cordon-Cardo, C. Defining molecular profiles of poor outcome in patients with invasive bladder cancer using oligonucleotide microarrays. J. Clin. Oncol. 24, 778–789 (2006).
Dyrskjot, L. et al. Identifying distinct classes of bladder carcinoma using microarrays. Nat. Genet. 33, 90–96 (2003).
Blaveri, E. et al. Bladder cancer outcome and subtype classification by gene expression. Clin. Cancer Res. 11, 4044–4055 (2005).
Birkhahn, M. et al. Predicting recurrence and progression of noninvasive papillary bladder cancer at initial presentation based on quantitative gene expression profiles. Eur. Urol. 57, 12–20 (2010).
Gui, Y. et al. Frequent mutations of chromatin remodeling genes in transitional cell carcinoma of the bladder. Nat. Genet. 43, 875–878 (2011).
Majewski, T. et al. Understanding the development of human bladder cancer by using a whole-organ genomic mapping strategy. Lab. Invest. 88, 694–721 (2008).
Smith, S. C. et al. A 20-gene model for molecular nodal staging of bladder cancer: development and prospective assessment. Lancet Oncol. 12, 137–143 (2011).
Ben-Porath, I. et al. An embryonic stem cell-like gene expression signature in poorly differentiated aggressive human tumors. Nat. Genet. 40, 499–507 (2008).
Glas, A. M. et al. Converting a breast cancer microarray signature into a high-throughput diagnostic test. BMC Genomics 7, 278 (2006).
Cronin, M. et al. Analytical validation of the Oncotype DX genomic diagnostic test for recurrence prognosis and therapeutic response prediction in node-negative, estrogen receptor-positive breast cancer. Clin. Chem. 53, 1084–1091 (2007).
Dinney, C. P. et al. Focus on bladder cancer. Cancer Cell 6, 111–116 (2004).
Wu, X. R. Urothelial tumorigenesis: a tale of divergent pathways. Nat. Rev. Cancer 5, 713–725 (2005).
Goebell, P. J. & Knowles, M. A. Bladder cancer or bladder cancers? Genetically distinct malignant conditions of the urothelium. Urol. Oncol. 28, 409–428 (2010).
Czerniak, B. et al. Concurrent mutations of coding and regulatory sequences of the Ha-ras gene in urinary bladder carcinomas. Hum. Pathol. 23, 1199–1204 (1992).
Billerey, C. et al. Frequent FGFR3 mutations in papillary non-invasive bladder (pTa) tumors. Am. J. Pathol. 158, 1955–1959 (2001).
Lopez-Knowles, E. et al. PIK3CA mutations are an early genetic alteration associated with FGFR3 mutations in superficial papillary bladder tumors. Cancer Res. 66, 7401–4 (2006).
Sarkis, A. S. et al. Nuclear overexpression of p53 protein in transitional cell bladder carcinoma: a marker for disease progression. J. Natl Cancer Inst. 85, 53–59 (1993).
Cordon-Cardo, C. et al. Altered expression of the retinoblastoma gene product: prognostic indicator in bladder cancer. J. Natl Cancer Inst. 84, 1251–1256 (1992).
Puzio-Kuter, A. M. et al. Inactivation of p53 and Pten promotes invasive bladder cancer. Genes Dev. 23, 675–680 (2009).
Ho, P. L., Lay, E. J., Jian, W., Parra, D. & Chan, K. S. Stat3 activation in urothelial stem cells leads to direct progression to invasive bladder cancer. Cancer Res. 72, 3135–3142 (2012).
Frank, N. Y., Schatton, T. & Frank, M. H. The therapeutic promise of the cancer stem cell concept. J. Clin. Invest. 120, 41–50 (2010).
Tatokoro, M. et al. Potential role of Hsp90 inhibitors in overcoming cisplatin resistance of bladder cancer-initiating cells. Int. J. Cancer 131, 987–996 (2011).
Falso, M. J., Buchholz, B. A. & White, R. W. Stem-like cells in bladder cancer cell lines with differential sensitivity to cisplatin. Anticancer Res. 32, 733–738 (2012).
Zhang, Y. et al. Cancer stem-like cells contribute to cisplatin resistance and progression in bladder cancer. Cancer Lett. (2012).
Diehn, M. et al. Association of reactive oxygen species levels and radioresistance in cancer stem cells. Nature 458, 780–783 (2009).
Willingham, S. B. et al. The CD47-signal regulatory protein alpha (SIRPa) interaction is a therapeutic target for human solid tumors. Proc. Natl Acad. Sci. USA (2012).
The authors would like to thank the National Cancer Institute (CA129640), V Foundation for Cancer Research (V Scholar Award), L E. Gordy and Josephine S. Gordy Memorial Cancer Research Fund, the Curtis Hankamer Basic Research Fund, the ARCO Foundation Young Teacher-Investigator Fund, and the CPRIT pre-doctoral fellowship for their funding support.
The authors declare no competing financial interests.
About this article
Cite this article
Ho, P., Kurtova, A. & Chan, K. Normal and neoplastic urothelial stem cells: getting to the root of the problem. Nat Rev Urol 9, 583–594 (2012). https://doi.org/10.1038/nrurol.2012.142
Nature Reviews Urology (2022)
Genome Biology (2021)
Immunohistochemical expression of stem cell markers ALDH1 and CD44 in urothelial carcinoma of the urinary bladder
Comparative Clinical Pathology (2021)
Der Pathologe (2021)
Expression of stem cell markers as useful complementary factors in the early detection of urinary bladder carcinogens by immunohistochemistry for γ-H2AX
Archives of Toxicology (2021)