EMERGENCE OF RESISTANCE TO VP-16 CISPLATIN CHEMOTHERAPY - STUDY IN A LYMPHOBLAST MODEL SYSTEM

Etoposide (VP-16) and cisplatin are widely used in the treatment of ma lignancy. It is a common clinical observation that patients may initia lly respond to this two drug combination but later become resistant to it. Data from the CCL-159 lymphoblast cell line suggests that the eme rgence of resistance may be by means other than multiple drug resistan ce gene expression. The data suggest that chemotherapeutic failure may be mediated in part by a relatively inefficient method of drug resist ance, the unstable expression of low-level drug resistance by a minori ty of cells. These results may help explain how patients whose maligna ncies are initially sensitive to VP-16/cisplatin later develop drug re sistance.