Detection of non-maternal components of gestational choriocarcinoma by PCR-based microsatellite DNA assay

OBJECTIVE: Gestational and non-gestational choriocarcinomas have distinctly different tissues of origin, parental genotypes, natural histories, and responses to therapy. Our objective was to develop a convenient, fast, and reliable assay that would, using only patient tissue, allow separation of gestational from non-gestational choriocarcinomas. METHOD: Benign and malignant tissues, preserved in paraffin blocks and separated by microdissection, were examined using a commercial PCR-based tissue identity assay (ABI AmpFlSTR Profiler Plus Kit and ABI 377 DNA sequencer) to detect genetic profiles of 9 microsatellite markers, along with X and Y chromosome markers. Cases included 6 choriocarcinomas. Controls included eight non-germ cell reproductive tract tumors and two hydatidiform moles. RESULTS: The microsatellite markers identified the five choriocarcinomas diagnosed on clinical and histological grounds as gestational, to be of genetically non-maternal (androgenic) origin. The neoplasm previously classified as a non-gestational choriocarcinoma was demonstrated to be of maternal origin, as were the non-germ cell reproductive tract tumors. Samples from hydatidiform moles contained either androgenic markers only or a mix of maternal and androgenic markers, as previously seen in complete and partial moles, respectively. CONCLUSION: A commercially available microsatellite DNA diagnostic assay is a quick and convenient way to discriminate between gestational and non-gestational choriocarcinoma.