Before revision:  Hyperthermia engages the heat-shock response mechanism (HSR), which main component (the heat-shock proteins ) is known to directly prevent the intended apoptosis of cancer cells. Moreover, cancer cells can have an already partially activated HSR, thereby  hyperthermia may be more toxic to them relative to normal cells.
After revision:  Hyperthermia engages the heat-shock response mechanism (HSR), which main component (the heat-shock proteins (HSP). Cancer cells have already partially activated HSR, thereby hyperthermia may be more toxic to them relative to normal cells.