The potential prognostic value of cathepsin D protein in serous ovarian cancer

Overexpression of a ubiquitous lysosomal aspartyl protease cathepsin D (cath-D) is involved in the progression of certain cancer types. This study investigated the prognostic value of the cath-D expression and its association with other known clinicopathological parameters in serous ovarian carcinoma.

Cath-D was detected by immunohistochemistry in 49 serous ovarian carcinomas and compared to 50 benign serous ovarian tumors. The results were correlated with clinicopathological characteristics and survival outcomes.

In both cath-D positive benign and malignant serous ovarian tumors, a specific granular cytoplasmic staining was observed in both epithelial and stromal cells. Cath-D expression levels were higher in serous ovarian carcinomas than in benign tumors (P < 0.01). Cath-D expression in tumor epithelial cells correlated with mesenchymal cell expression (P < 0.001). The cath-D expression levels of tumor epithelial cells correlated with residual tumor size (P = 0.027) and was not related to other factors (P > 0.05). Patients with higher cath-D expression in epithelial cells had longer disease-free survival time (DFST; P = 0.025) and overall survival time (OST; P = 0.030). Through the Cox regression test, we found that the response to treatment (P < 0.001), pathological stage (P < 0.001), and peritoneal cytology results (P = 0.018) were independent effect factors for DFST. The expression level of cath-D in epithelial cells (P = 0.025), response to treatment (P < 0.001), pathological stage (P = 0.001), and peritoneal cytology results (P = 0.002) were independent effect factors for OST.

This showed that cath-D was an indicator of malignancy in serous ovarian carcinoma. It was expressed more highly in serous ovarian carcinoma than benign serous ovarian tumor. Additionally, our results suggested that high expression of cath-D in tumor epithelial cells was a favorable survival prognostic factor for serous ovarian carcinoma.