245 Microarray Profile of Benign Ovarian Tumor is Analogous to Early-Stage Ovarian Carcinoma

Ovarian cancer (OC) is the primary cause of gynecological cancer death. Microarray is certainly a promising tool to search for a sensitive and specific screening marker for early detection and is being used extensively. We employed cDNA array containing 9,600 genes to study 47 ovarian tumors, 28 OCs (15 stage I, 13 stage III) and 46 normal tissues. We found that expression profiles of early-staged OC tissues are highly correlated to benign ovarian tumors with correlation coefficient equaling 0.87, while malignancies from other types of organ showed only limited resemblance to ovarian tumor with correlation coefficient less than 0.5. Cluster analysis indicated that benign tumor presented expression profiles indistinguishable to early-staged OCs. Benign ovarian tumor could be considered as pre-cancerous stage instead of non-cancerous stage as previously assumed. By treating benign ovarian tumor as pre-cancerous stage and comparing to later stages of OC we identified 46 genes overly expressed in early-staged cancer with P < 0.01. It is likely that genes isolated could serve as valuable diagnostic molecular markers for early detection of OC. We identified transcripts that show stage-specific expression in ovarian tumor/cancer tissue as compared to normal ovary tissue. Additionally, we identified 74 over-expressed genes at all stages of ovarian tumor/cancer with p < 0.001. We also identified 37 genes down-regulated at all stages of ovarian tumor/cancer with P < 0.01. The expression for selected genes was confirmed by semi-quantitative RT-PCR. JUN and nuclear receptor subfamily 2 genes were repeatedly identified in this group indicating their important regulatory roles in the oncogenesis of ovary.