Epidemiological Study of Infant Leukemia on Kyushu Island between 1990-1994

Abstract

Recent studies have demonstrated that mutations including MLL gene initiating infant leukemia can arise in the uterus during pregnancy. In this study, we performed clinical and epidemiological studies of the patients with infant leukemia who were diagnosed and treated on Kyushu Island between 1990-1994. The proportion of infant leukemia for childhood leukemia was 7.5%; 5.0% in ALL and 13.1% in AML. The incidence of infant leukemia in the same period was 3.96/100, 000 infants/year. However, the proportion and incidence of infant leukemia in the Kyoto area was definitely high ; 12.9% for childhood leukemia and 5.60/100, 000 infants/ year. On Kyushu Island, all but one AML patient who showed 11q2/MLL abnormality were less than 10 months old at diagnosis. Most of the ALL patients with 11q23/ MLL abnormality dieddespite intensive therapy. In a case-control study on risk factors, maternal exposure to organic compounds was found to increase the risk of infant leukemia. In the Kyoto area, other exposures were also found to increaserisk, including antibiotics, herbal medicine or viral infection. These findings suggest some reagents with topoisomerase II inhibiting activity may induce fetal abnormalities or leukemogenesis. An international collaboration study will clarify this hypothesis in the near future.