Overexpression of cytokeratin 17 protein in oral squamous cell carcinoma in vitro and in vivo

To determine the cytokeratin 17 (CK17) expression in oral squamous cell carcinoma (OSCC) both in vitro and in vivo. Comparative proteomic analysis of an in vitro cellular carcinogenesis model of OSCC (including a line of human immortalized oral epithelia cells (HIOECs), a line of cancerous HB96 cells and another kind of cells (HB56 cells) at the early stage of carcinogenesis was performed to identify differentially expressed proteins. CK17 was further validated in vitro (cellular carcinogenesis model and other three OSCC lines) and in vivo (tissues from six healthy persons and 30 primary OSCC patients) by Western blotting and immunohistochemistry respectively. Increased CK17 expression was identified by two-dimensional gel electrophoresis and liquid chromatography-tandem mass chromatography in the HB56 and HB96 cells over HIOECs. Western blotting confirmed the increased CK17 expression in the HB56, HB96 cells and other three OSCC lines. Immunohistochemistry confirmed the increased CK17 expression in the cancerous tissues from OSCC patients compared with the paired adjacent non-malignant epithelia. Increased CK17 expression may play an important role in the carcinogenesis progression of OSCC; however, further studies on the molecular function of CK17 are encouraged to clear the precise mechanism of CK17 in OSCC.