Genetic analysis of childhood endodermal sinus tumors by comparative genomic hybridization

Childhood endodermal sinus tumors (CEST) are a distinct category of germ cell tumors that involve the testis and extragonadal sites of young children. Recurrent deletions of 1p and 6q have been reported by classic cytogenetic analysis of a small number of cases. Comparative genomic hybridization, a technique that screens the entire genome for genetic abnormalities, is applied to additionally define the genetic changes present in CESTs. Sixteen frozen CESTs (10 testicular, 6 extragonadal) obtained from Pediatric Oncology Group-affiliated institutions or from the Cooperative Human Tissue Network were analyzed. The most common changes were gain of 20q (10 tumors), 1q (6 tumors), 11q and 22 (4 tumors each), and loss of 6q (8 tumors with common deleted region of 6q24-qter), 16q (4 tumors), and 1p (4 tumors). Localized regions of gain were identified at 8q24 (2 tumors both showing c-myc amplification by fluorescence in situ hybridization). Gain of 12p, characteristic of adolescent germ cell tumor, was present in one testicular tumor. Comparative genomic hybridization was useful in defining genetic differences between adult and childhood tumors, in determining the common regions deleted on chromosome 6, and in identifying other involved loci to be correlated with clinical parameters in future studies.