The age incidence of childhood acute lymphoblastic leukaemia.

A mathematical model of childhood acute lymphoblastic leukaemia (ALL) is presented which is based on the assumptions that: 1) malignant clones of lymphoblasts arise by spontaneous mutation; 2) this is normally prevented by repair systems which either cause intracellular DNA repair or eliminate the malignant clone; and 3) the repair systems are fallible and their performance decays at random with time. If the major drive to lymphocyte division is microbial antigens then the model produces a reasonable fit to published data on the age distribution of ALL. Furthermore the model offers an explanation for the apparent increase in the incidence of ALL which is associated with improved social conditions.