Human epididymis protein 4 expression positively correlated with miR-21 and served as a prognostic indicator in ovarian cancer

Ovarian cancer is the most common cause of gynecological malignancy-related mortality. Human epididymis protein 4 (HE4) is a useful biomarker for ovarian cancer when either used alone or in combination with carbohydrate antigen 125 (CA125). What is more, aberrant expression of microRNA-21 (miR-21) has been shown to be involved in oncogenesis, but the relationship between miR-21 and HE4 in ovarian cancer is not clear. Tumor and adjacent tumor tissues from 43 patients with ovarian cancer were examined. Real-time polymerase chain reaction (RT-PCR) was used to detect the expression of HE4 in the carcinoma and adjacent tissues. The associations between HE4 and tumor biological characters were discussed. TaqMan^® MicroRNA (miRNA) assays were employed to detect the expression of miR-21 in the ovarian carcinoma. In ovarian cancer, the expression of HE4 messenger RNA (mRNA) in cancer tissues was higher than adjacent tumor tissues (P < 0.0001), which was 1.299-fold of adjacent tumor tissues. And, the expression of miR-21 was also up-regulated which was significantly different in the ovarian cancer (the positive rate was 76.74 %). There was a significantly positive correlation between miR-21 and HE4 expression (r = 0.283 and P = 0.066 for HE4 mRNA, r = 0.663 and P < 0.0001 for serum HE4). There was also a significant correlation between miR-21 and tumor grade (r = 0.608, P < 0.0001). Significantly, patients with recent recurrence (less than 6 months, n = 17) have a higher miR-21 expression than those with no recent recurrence. Therefore, HE4 and miR-21 may play an important role in the development and progression of ovarian cancer and they may serve as prognostic indicators in ovarian cancer.