Mutation selection and tumour progression

It is proposed that tumour progression results from the increased mutability of tumour cells and that this mutability leads to the acquisition of a large number of 'neutral' mutations having no significant effects under physiological conditions but capable of lethal expression under different conditions. High temperatures often lead to expression of neutral mutations and this could provide a mechanism for the observed thermosensitivity of tumour cells, and a rational basis for the use of hyperthermia in cancer treatment.