Evaluation of serum mesothelin in malignant and benign ovarian masses

To evaluate the diagnostic accuracy of serum mesothelin levels in patients with ovarian masses in comparison to serum cancer antigen (CA) 125 levels. This diagnostic accuracy study was conducted in a gynecological oncology unit at Ain Shams University Maternity hospital. Based on radiological and clinical findings, a total of 110 patients were consecutively recruited. Preoperative serum mesothelin levels were assessed using enzyme-linked immunosorbent assay (ELISA) technique, while CA125 levels were determined using electrochemiluminescence immunoassay. All patients underwent exploratory laparotomy. Preoperative serum levels of both markers were correlated to histopathological reports obtained from each patient. A total of 96 patients were finally analyzed. Of the included 96 patients, 58 (60.4 %) had a benign ovarian lesion, while 38 (39.6 %) had a malignant lesion. The median serum CA125 levels were significantly higher in patients with malignant ovarian lesions than in patients with benign ovarian lesions [335.5 mIU/mL (range 60-1,127 mIU/mL) versus 33.65 mIU/mL (range 10.36-174 mIU/mL), P < 0.001]. The median serum mesothelin level was significantly higher in patients with malignant ovarian lesions than in patients with benign ovarian lesions [104.1 nmol/L (range 6.5-215.4 nmol/L) versus 12.65 nmol/L (range 6.5-102 nmol/L), P < 0.001]. The diagnostic sensitivity and specificity for mesothelin and CA125 were 97.4 and 98.3 % and 97.4 and 56.9 %, respectively. The combination of mesothelin with CA125 did not add predictive value to mesothelin compared with mesothelin alone [same sensitivity (97.4 %) and same specificity (98.3 %)]. Serum mesothelin levels rather than serum CA125 levels were a significant predictor of early-stage ovarian malignancy [Area under the curve = 0.732, 95 % confidence interval (0.543-0.921), P = 0.031]. In ovarian cancer, mesothelin seemed to have the same sensitivity, but a higher specificity than CA125. Combination of mesothelin and CA125 had no advantage over mesothelin alone. Mesothelin rather than CA125 was a significant predictor of early-stage ovarian cancer (stage I/II).