Clinical Significance of Microsatellite Instability in Sporadic Epithelial Ovarian Tumors

Abstract: CONCLUSION: MSI was infrequent in ovarian tumors, including both borderline and malignant tumors. MSI was found to be uncommon in sporadic ovarian tumors, even by using additional MSI markers. The clinical significance of MSI is not strong in patients with sporadic ovarian tumors.

Link to full text (pdf file):

DISCUSSION
....MSI is caused by mutations in the mismatchrepair genes (MMR). MSI has been implicated in the pathogenesis of colon, endometrial, and gastric
carcinomas that occur in the setting of HNPCC (Lynch Syndrome), and also in a subset of sporadic cancers such as upper urinary tract, stomach, colon, andendometrial carcinomas.
In ovarian cancers, the reported incidence of MSI ranges from 0 to 37%, depending on the number and type of markers. Sood et al. first
reported the incidence of MSI in ovarian cancer using the NCI criteria.....Therefore, further study of molecular events that are correlated with ovarian tumors is needed."

MicroRNA (miR-155) Linked To Shut-Down Of DNA-Repair Genes

In research:

"The study, led by researchers at the Ohio State University Comprehensive Cancer Center-Arthur G. James Cancer Hospital and Richard J. Solove Research Institute, shows that microRNA-155 (miR-155) can inhibit the activity of genes that normally correct the damage when the wrong bases are paired in DNA.

The loss or silencing of these genes, which are called mismatch repair genes, causes inherited cancer-susceptibility syndromes and contributes to the progression of colorectal, uterine, ovarian and other cancers."

"Overall, Croce says, "Our findings suggest that miR-155 expression might be an important stratification factor in the prognosis and treatment of cancer patients and provide an additional analytical test for exploring the etiology of microsatellite-instability tumors when the standard tests do not provide a conclusive diagnosis."