Overexpression of chloride channel-3 (ClC-3) is associated with human cervical carcinoma development and prognosis.

Background: Cervical carcinoma is a major gynecological cancer and causes cancer-related deaths in worldwide, the latent pathogenesis and progress of cervical cancer is still under research. ClC-3 may be an important promoter for aggressive metastasis of malignant tumors. In this research, we explore the ClC-3 expression in cervical carcinoma and its underlying clinical significance, trying to illuminate ClC-3 probable function in the neoplasm malignant behavior, development and prognosis.

Methods: Paraffin-embedded cervical (n = 168) and lymph node (n = 100) tissue specimens were analysed by immunohistochemistry. Fresh human cervical tissue specimens (n = 165) and four human cervical cell lines were tested for ClC-3 mRNA and protein expression levels by quantitative real-time PCR and western blotting. The relationship between the expression levels of ClC-3, the pathological characteristics of the carcinoma, and the clinical prognosis were statistically analysed.

Results: In normal and precancerous (LSIL, HSIL) cervical tissues as well as cervical carcinoma tissues, both ClC-3 mRNA and protein expression levels increased significantly ( p  < 0.05). The expression level of ClC-3 was closely-related to the histological differentiation (p = 0.029), tumour staging ( p  = 0.016), tumour size ( p  = 0.039), vascular invasion ( p  = 0.045), interstitial infiltration depth ( p  = 0.012), lymphatic metastasis ( p  = 0.036), and HPV infection ( p  = 0.022). In an in vitro experiment, ClC-3 mRNA and protein were found to be overexpressed both in the HeLa and SiHa cell lines, but low expression levels were detected in the C-33A and H8 cell lines ( p  < 0.05). Furthermore, the high expression levels of ClC-3 was significantly correlated to poor survival in cervical carcinoma patients (Log-rank test, p  = 0.046).

Conclusions: These data suggest that overexpression of ClC-3 is closely associated with human cervical carcinoma progression and poor prognosis; this suggests that ClC-3 may function as a patent tumour biomarker and a latent therapeutic target for cervical carcinoma patients.