Epidemiological and molecular biological study of familial factors in occurrence of children's leukemia

目的：一些证据表明，一些儿童白血病起源于子宫，并在一个或多个额外的遗传事件后发展为显性白血病。如果突变的频率与DNA复制的频率成正比，那么在产生精子的精原细胞活跃分裂中，老年男性比年轻男性积累的这种突变要多，因此患有白血病的孩子的父亲可能比没有癌症的孩子的父亲年龄大。方法：急性淋巴细胞白血病（ALL）、急性骨髓性白血病（AML）、神经母细胞瘤或肝母细胞瘤患儿出生时父母年龄数据由日本儿童癌症登记处提供。以5家医院急性病患儿家长资料为对照。结果：2 ~ 6岁ALL患儿家长年龄分布曲线完全重合。ALL患儿父亲和母亲的SD平均年龄分别为383.5 +/- 67.1个月和348.9 +/- 53.3个月。对照组分别为382.6 +/- 65.3和349.4 +/- 54.6。其他年龄段的ALL患儿，AML和胚胎性肿瘤（神经母细胞瘤、肾母细胞瘤、肝母细胞瘤）的结果相似。结论：患癌儿童的父亲和母亲的年龄没有显著差异。老年父母可能在精子或卵子中积累了致癌突变的假设没有得到证实。

Objectives : Several evidences showed that some of children's leukemia have their origin in utero and they develop into overt leukemia after one or more additional genetic events. If frequency of mutation is proportional to frequency of DNA replication, active cell division of spermatogonia to produce sperm can accumulate such mutation much more in older male than young male and as the result father of children with leukemia might be older than father of children without cancers. Methods : Data of ages of parents at the time of birth of children with acute lymphocytic leukemia (ALL), acute myelogenous leukemia (AML), neuroblastoma or hepatoblastoma were provided by the Children's Cancer Registry of Japan. Data of parents of children who visited 5 hospitals for acute illness were served as control. Results : Distribution curves of ages of parents of children with ALL diagnosed at the ages between 2 to 6 years were completely overlapped. Mean ages with SD of father and mother of children with ALL were 383.5 +/- 67.1 months and 348.9 +/- 53.3, respectively. Those of controls were 382.6 +/- 65.3 and 349.4 +/- 54.6, respectively. The results for the children with ALL of other age ranges, AML and embryonal tumors (neuroblastoma, Wilms tumor, hepatoblastoma) were similar. Conclusion : There were no significant differences between ages of either fathers or mothers of children with cancers examined. Hypothesis that older parents might have accumulated carcinogenic mutations in their sperm or ovum was not substantiated.