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 rep orted previously. The patients ranged in age from 23 weeks gestation t o 16 years. The tumors were located in the ovary, sacrococcygeum, test is, mediastinum, and the craniofacial region, and represented benign, immature, and malignant cases. All of the new cases had a normal diplo id karyotype. We have previously reported on multiple genetic mechanis ms of origin for ovarian germ cell tumors, namely meiosis I nondisjunc tion, meiosis II nondisjunction, endoreduplication of a haploid ovum, mitotic division of premeiotic germ cell, and fusion of two ova. To de termine the origin of extragonadal and testicular GCTs, Q-band centrom eric 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; rat her, they arise mitotically from either a somatic or a germ cell.