Human cancers express a mutator phenotype: Hypothesis, origin, and consequences

Abstract

The mutator phenotype hypothesis was postulated more than 40 years ago. It was based on the multiple enzymatic steps required to precisely replicate the 6 billion bases in the human genome each time a normal cell divides. A reduction in this accuracy during tumor progression could be responsible for the striking heterogeneity of malignant cells within a tumor and for the rapidity by which cancers become resistant to therapy.