A hyperthermia study of differential sensitivity and thermotolerance in AKR murine leukemia and normal bone marrow cells.

It has been previously demonstrated that AKR leukemia (lymphoma) cells are more sensitive than normal bone marrow cells to hyperthermic killing at 41.8 degrees C and 42.5 degrees C in vitro. This differential heat sensitivity might be explained by a greater ability to induce thermotolerance (TT) in normal versus neoplastic hematopoetic cells. We tested this hypothesis using the spleen colony methodology in the AKR murine model. A greater heat sensitivity of leukemia in comparison to normal bone marrow cells was observed at 42.5 degrees C; this observation agrees with previous reports. However, using a preincubation temperature of 40.0 degrees C for 120 min did not result in the induction of TT in either normal bone marrow (AKR) cells or AKR leukemia cells. The rationale for the choice of preincubation temperatures and times, as well as the clinical implications of these results are discussed.