CYTOGENETICS AND ORIGINS OF PEDIATRIC GERM-CELL TUMORS

We present cytogenetic and DNA fingerprint analysis on 13 new cases of pediatric germ cell tumors; we analyze further four cases we have reported previously. The patients ranged in age from 23 weeks gestation to 16 years. The tumors were located in the ovary, sacrococcygeum, testis, mediastinum, and the craniofacial region, and represented benign, immature, and malignant cases. All of the new cases had a normal diploid karyotype. We have previously reported on multiple genetic mechanisms of origin for ovarian germ cell tumors, namely meiosis I nondisjunction, meiosis II nondisjunction, endoreduplication of a haploid ovum, mitotic division of premeiotic germ cell, and fusion of two ova. To determine the origin of extragonadal and testicular GCTs, Q-band centromeric heteromorphisms and DNA markers were analyzed in the host and the cognate tumor. Our data suggest that extragonadal and testicular GCTs do not arise by a meiosis I or II error, or by endoreduplication; rather, they arise mitotically from either a somatic or a germ cell.