Evaluation of miR-22 and miR-21 as diagnostic biomarkers in patients with epithelial ovarian cancer.

Abstract

Among the 11 most common cancers, ovarian cancer is the fifth leading cause of death after lung, breast, colorectal and pancreatic cancer. Although diagnosis of ovarian cancer in early stages is followed by various successful treatments, no accurate and reliable method is available at present. Currently microRNAs are being explored as signature biomarkers for early detection of various types of cancer. However little information is available on expression and correlation of microRNA in ovarian cancer. In this study, we have chosen two microRNA on the basis of their altered frequency in epithelial ovarian cancer cases. The main objective of this study is to evaluate the expression of microRNA-22 and microRNA-21 along with various clinicopathological parameters. Expression level of microRNA-22 and microRNA-21 in different stages and subtypes of epithelial ovarian carcinoma has been analyzed to find out its role as a potential diagnostic biomarker. Present study has been conducted in the serum of 80 epithelial ovarian cancer patients and 80 age matched healthy women. Quantitative real time PCR was used to compare the expression of miR-22 and miR-21 between the cases and control groups. Statistical analysis showed 7.85-fold increase in miR-21 expression and 2.1-fold reduction in miR-22 expression of ovarian cancer patients. Increased serum level of miR-21 in ovarian cancer patients and decreased level of miR-22 has been correlated with advanced international federation of gynecology and obstetrics (FIGO) stage and histological sub types of epithelial ovarian cancer. Serous ovarian carcinoma was the most common cancer in the present study. Calculated fold change value for miR-21 was 3.98 and - 2.86 for miR-22 in serous ovarian cancer. Fold change value in the miR-21 expression in advanced stage was 6.29 and 4.25 in early stage. Whereas lower calculated fold change was observed for miR-22 in advanced stage than in early stage (- 2.16). Present study revealed up-regulated expression of miR-21 and down regulated expression of miR-22 in the serum of epithelial ovarian cancer patients. Both of these could be validated as good diagnostic biomarkers for early detection of ovarian cancer.