Objectives: To determine the CA125 tissue expression levels in borderline and invasive epithelial ovarian tumor tissues. Secondly, to evaluate whether CA125 tissue expression levels correlate with clinico-pathological parameters and serum CA125 levels and finally to investigate the prognostic value of tissue CA125 expression levels in ovarian cancer (OC) patients.
Methods: We designed tissue arrays (TA) and analyzed the CA125 expression in tissues from 778 Danish women with an ovarian tumor. Furthermore, corresponding preoperative blood samples obtained before surgery were collected from 382 women with OC.
Results: Significantly more CA125 expression positive tumors (no expression vs. expression) were found in the serous subtype compared to the percentage of positive tumors in mucinous, endometroid and other subtypes for patients both with borderline ovarian tumors and with OC (p<0.00001, p<0.00001). Similarly, a positive significant correlation was found between elevated serum CA125 levels and elevated levels of CA125 tissue expression (N=382 stage I-IV OC, Spearman rho=0.31, p<0.0001) (N=206 stage III OC, Spearman rho=0.30, p<0.0001). We found a significantly shorter survival for stage III/IV OC patients with no CA125 tissue expression compared to stage III/IV OC patients with positive CA125 tissue expression (p=0.0003).
Conclusion: Our finding that tissue CA125 expression was lacking in late stage primary OC tumor of Danish women with poor survival may be of value in selecting patients as eligible candidates for individually based treatments.