No evidence for microsatellite instability from allelotype analysis of benign and low malignant potential ovarian neoplasms

The genetic events that lead to the development of benign and low malignant potential (LMP) tumors from normal ovarian surface epithelium are not well understood. In contrast to invasive ovarian neoplasms, loss of heterozygosity (LOH) is not common in these tumors except on the X chromosome, but one report has suggested that an alternative genetic mechanism, microsatellite instability (MSI), might be an important pathogenic mechanism for LMP ovarian tumors. Objective. To determine the frequency of MSI in LMP tumors and to detect novel regions of LOH in benign and LMP ovarian tumors. Methods. Sixty-nine microsatellite markers were analyzed in 23 benign and 31 LMP ovarian tumors. Results. No evidence of MSI was found in any of the tumors studied, nor were any novel regions of LOH identified. Conclusions. This suggests that new approaches may be necessary to understand the genetic basis of benign and LMP ovarian neoplasms since neither LOH nor MSI appears to play a major role. (C) 1998 Academic Press.