PAX8 is a potential marker for the diagnosis of primary epithelial ovarian cancer.

The present study aimed to investigate the clinical significance of paired-box 8 (PAX8) in primary epithelial ovarian cancer (PEOC). Using immunohistochemical (IHC) staining, the expression of PAX8 in 60 patients with PEOC, 20 patients with ovarian benign lesions and 10 patients with metastatic ovarian cancer (MOC), was examined based on the clinicopathological profiles of the patients. The correlation between PAX8 expression and the clinicopathological parameters or prognosis of patients was statistically analyzed. PAX8 was revealed to be highly expressed in PEOC, but not in MOC, as indicated by IHC staining. The rate of positivity of PAX8 in PEOC was 92% (57/60) with no significant difference of PAX8 expression found between the various pathological types of PEOC (P=0.871). The rate of positivity of PAX8 in ovarian benign tumors was 85%, demonstrating no significant difference in comparison with that of PEOC (P=0.761). PAX8 staining and statistical analysis revealed that the higher the grade of PEOC, the less the cancer cell had differentiated (P=0.033) and the more the cancer had advanced according to International Federation of Gynaecological Oncologists (FIGO) staging (P=0.003). Survival rate statistics showed that PEOC patients with higher PAX8 expression exhibited a shorter postoperative survival rate (P=0.009). PAX8 was specifically expressed in PEOC, and its expression level was associated with the degree of cancer cell differentiation, FIGO stage, and survival rate, indicating that PAX8 is a potential marker for the diagnosis of PEOC.