Quantitative analysis of resistance and cross-resistance to cytotoxic agents by tumour cell lines.

The published literature describing the spectrum of resistance and cross-resistance to cytotoxic agents by human and murine tumour cell lines maintained in long-term culture is reviewed. The data available demonstrate that for many cytotoxic agents, especially those of higher molecular weight, cross-resistance is proportional to the degree of resistance against the selecting agent. Furthermore, the degree of cross-resistance correlates with the molecular weight of the drug in adriamycin-, vincristine- and colchicine-resistant cell lines.