Etiology of leukemia. A review.

A variety of factors probably are etiologically involved in leukemia, not only in different cases but also within individual cases. Abnormalities of chromosomes have been found in various types of leukemia. Whether these chromosomal alterations are primary or secondary is undetermined, but it is likely that they are at least contributory in the development of leukemia. There is an increasing body of evidence incriminating viruses in leukemogenesis in man, and they may be a factor in all cases. Certain chemicals may be important etiologic factors in a few cases. Many different studies have established that ionizing radiation in large doses may be leukemogenic. Whether small doses of irradiation are dangerous has not been demonstrated.