Enhanced chemosensitivity of cells from malignant effusions under condition of exposure to high temperature

Utilizing a clonogenic assay, the effects of hyperthermia and selected chemotherapeutic drugs on growth of cells from malignant effusions were studied. Fourteen of 25 samples obtained from 25 patients with various carcinomas formed at least 30 colonies per plate. Exposure of the cells to heat at 42 degrees C for 1 hr before the plating slightly inhibited the colony growth. The drugs, adriamycin (AM) and mitomycin C (MMC), were tested at 3 different concentrations. When the cells were treated with these two drugs for 1 hr at 42 degrees C, the percent of surviving colonies was significantly decreased, as compared to findings at 37 degrees C, in both groups, at 3 different concentrations. The combination of drugs and hyperthermia appeared to function synergistically in one-third of such cases. These results suggest that cells from malignant effusions in patients with various carcinomas were more sensitive to AM or MMC, under condition of a higher temperature (42 degrees C).