Cathepsin B may be a potential biomarker in cervical cancer.

Cathepsin B is a protease which is able to digest extracellular matrix. It is currently unknown whether cathepsin B plays a role in cervical cancer development and progression. With Q-PCR and Western blotting, we observed cathepsin B expression in cervical cancer cell line Hela cells. After the gene was silenced in HeLa cells with SiRNA, we confirmed that cathepsin B expressions at both mRNA and protein levels were significantly reduced. At the same time, cell proliferation, migration and invasion of the HeLa cells were significantly decreased compared to control cells. In addition, a significant regression of tumor growth in nude mice which received the siRNA targeted cathepsin B HeLa cells was observed. We further studied the expression of cathepsin B in a series of 169 clinical samples, including 56 invasive cervical squamous carcinoma, 85 CINs and 28 normal cervical tissues. It was found that cathepsin B expression in invasive carcinomas was significantly higher than that in the CINs and normal tissues (P<0.01). In addition, cathepsin B expression in the invasive carcinomas was positively correlated to tumor invasion depth and lymphatic metastasis. Our results indicate that cathepsin B may be a potential biomarker for further strategical clinical studies in cervical cancer.