Hyperthermia-induced cell death by apoptosis in myeloma cells.

We have analyzed by morphological (TEM) and histochemical (TUNEL reaction) criteria the type of cell death occurring in one case of human multiple myeloma after hyperthermia. Samples of cells examined immediately at the end of two treatments with a 15-day interval showed a significant degeneration, mostly demonstrating features of apoptosis (cell shrinkage, DNA fragmentation, karyorrhexis). The possible causes of the lag period between heating and apoptosis onset-expression are discussed.