in Ovarian Carcinoma

Previous allelotyping studies of epithellal ovarian carcinoma suggest that loss of heterozygosity on chromosome 14q may be a common genetic alteration In this tumor type. The purpose of this study was to determine a precisefrequency of chromosome 14qalleliclossin ovariancarcinomas and to define a ininimsl region(s) of deletion. Seventy-six ovarian carci nomasrepresentative of the completespectrumof grade,stage, and histological subtype were selected for PCR-based deletion mapping anal ysis using 15 hIghly polymorphicmicrosatellitemarkers spanning the length of this chromosome arm. Loss of heterozygosity was observed in 49% of the tumors studied, placing 14q among the most frequently affected chromosomal regions in ovarian cancer. Deletions were observed in all tumor grades and stages and in all histological subtypes except tumors oflow malignant potential. Deletion ofthe entire chromosome arm was rnre the majority of tumors displayed partial losses, providing an informative basis for detailed deletion mapping. Two distinct minimal regions of deletion were delineated. One region was defined by markers D14S80 and D14S75 at 14q12â€"13, and the other region was defined by markersD14S65andD14S267 at 14q32.Thesedata implicatethe involve ment of two tumor suppressor genes on chromosome 14q in a substantial fraction of ovarian carcinomas.