Cancer incidence rises with age. (A) The incidence of solid tumor cancers derived from somatic cells increases exponentially with age. The circle marks the inflection point at the transition between the early (E) slope and steep (S) slope. (B) The effect of sirtuin gene expression on lifespan. This is a graphical summary of data obtained from increased or decreased sirtuin expression in C. elegans. Overexpression of sirtuin genes results in increased lifespan (curve C), whereas underexpression of these genes shortened lifespan (curve B). The time of the inflection point (circle) is shifted, but the general shape of the survival curve remains unchanged.