Early Detection

Visualization of tumors and metastases in live animals with bacteria and vaccinia virus encoding light-emitting proteins. Yu Y. A. et al. Nature Biotechnol. 8 Feb 2004 (doi:10.1038/nbt941)

Yu et al. show that microorganisms can preferentially survive and replicate in tumours. Bacteria and vaccinia virus engineered to express green fluorescent protein were visualized by real-time imaging in tumour-bearing rodents. Two days after injection, light emission was only observed in tumours and metastases, and after 45 days was still present in the primary tumour. So, microorganisms might be useful for cancer detection and treatment.

Metastasis

Treatment of terminal peritoneal carcinomatosis by a transducible p53-activating peptide. Snyder, E. L., Meade, B. R., Saenz, C. C. & Dowdy, S. F. PLoS Biol. 2, 1–8 (2004)

Metastatic disease is difficult to treat. An alternative to gene therapy is systemic delivery of tumour-suppressors. This approach is also limited, however, as the large proteins cannot cross the plasma membrane. Snyder et al. have delivered a p53-activating peptide to mice with terminal metastatic disease using peptides containing a protein transduction domain. p53 was activated in cancer cells, but not normal cells, and resulted in increased lifespan and disease-free animals.

Therapeutics

Application of gene expression-based high-throughput screening (GE-HTS) to leukemia differentiation. Stegmaier, K. et al. Nature Genet. 36, 1–7 (2004)

Stegmaier et al. developed GE-HTS as a cell-based approach to screen chemical libraries for compounds that regulate biological processes. They used GE-HTS to identify compounds that cause differentiation of acute myeloid leukemia (AML) cells. Of the 1,739 compounds screened, 8 induced the GE-HTS AML differentiation signature and could induce at least one hallmark of differentiation assayed by conventional methods. This approach will be useful for dissecting the mechanisms that regulate AML differentiation.

Immunotherapy

High vaccination efficiency of low-affinity epitopes in antitumor immunotherapy. Gross, D. -A. et al. J. Clin. Invest. 113, 425–433 (2004)

Cancer vaccines should help the immune system into recognizing tumour cells. But, most tumour-associated antigens — which are used to make the vaccines — are also expressed on normal cells and cause autoimmunity to develop. Gross et al. report that low-affinity epitopes of TERT, a protein preferentially expressed in cancer cells, induce tumour immunity without causing autoimmunity. So, selection of low-affinity epitopes might overcome the problems associated with existing cancer vaccines.