[Environmental factors for the development of hematopoietic neoplasms in children].

Parental age at birth has been investigated in patients diagnosed with pediatric cancer. The Japan Children's Cancer Registry1985-2007 recruited 5,510 patients with leukemia and 8,782 with other cancers. The proportion of patients born to mother and father aged >40 years showed a higher trend in leukemia than that in other cancers (odds ratio [OR] 1.