Melanoma-initiating cells could be targeted in tx resistance

Cambridge, Mass. - Researchers at Harvard Medical School have identified a population of cells capable of initiating human melanomas, which could be targeted in cases of resistance to systemic therapy, HealthDay News reports.

The Harvard study, which appears in the Jan. 17 issue of Nature, examines whether expression of the chemoresistance mediator ABCB5 defines a population of human malignant-melanoma initiating cells, based on the knowledge that this marker defines progenitor cells in the skin.

Tobias Schatton, PharmD., and colleagues found that in melanoma patients, ABCB5-positive tumor cells had a primitive molecular phenotype and correlated with clinical melanoma progression. In mice, ABCB5-positive cells were more tumorigenic than ABCB5-negative cells, and ABCB5-positive cells gave rise to cells that were either positive or negative for the marker.

An ABCB5-specific monoclonal antibody known to induce antibody-induced cell death inhibited the growth of tumors expressing the marker.

The study concludes that identification of tumor-initiating cells with enhanced abundance in more advanced disease, but with susceptibility to specific targeting through a defining chemoresistance determinant, may well have important implications for cancer therapy.