Molecular genetic analysis of malignant ovarian germ cell tumors

OBJECTIVE: Relatively little is known about the molecular mechanisms involved in the initiation and progression of ovarian germ cell tumors (OGCTs), in contrast to testicular germ cell tumors (TGCTs) which have been extensively investigated. Ovarian germ cell tumors share many pathological and biological features with TGCTs and it is likely that they share similar molecular genetic alterations, although this has not been studied in detail. The aim of this study was to compare and contrast loss of heterozygosity (LOH) in OGCTs at chromosomal regions that are commonly involved in TGCTs. METHODS: Universal amplification was performed on 35 paired specimens of malignant OGCT and constitutional DNA that had been microdissected from single paraffin-embedded tissue sections in 32 patients. Sixty-two microsatellite markers were used to assess LOH at chromosomal regions mapping to 3q, 5q, 9p, 11p, 11q, 12q, 17p, and 18q as these are commonly involved in testicular germ cell tumors. RESULTS: Assessment of these regions demonstrated common sites of deletion at 3q27-q28 (50%), 5q31 (33%), 5q34-q35 (46%), 9p22-p21 (32%) and 12q22 (53%) in all histological subtypes of OGCT. We and others have previously found these regions to be frequently deleted at early stages of tumor development in TGCTs. CONCLUSIONS: These chromosomal regions may contain tumor suppressor genes that are important in the initiation and progression of both malignant OGCTs and TGCTs.