Among CKs, CK17 should be focused as a diagnostic marker of OSCC, since several studies have reported that the expression of CK17 could be detected in malignant tissues compared to normal tissues in squamous cell carcinoma of lung (Wetzels et al. 1992), cervix (Carrilho et al. 2004; Ikeda et al. 2008), larynx (Cohen-Kerem et al. 2004), and esophagus (Takahashi et al. 1995; Luo et al. 2004). The gene discussed is KRT17; the disease is squamous cell carcinoma.