FAK and Src expression in mobile tongue squamous cell carcinoma: associations with clinicopathological parameters and patients survival

Abstract

Focal adhesion kinase (FAK) and Src are protein tyrosine kinases, localized in the focal adhesions, which, upon activation interacts each other, regulate several cellular signaling pathways implicated in malignant transformation and disease progression. The present study aimed to evaluate the clinical significance of FAK and Src protein expression in mobile tongue squamous cell carcinoma (SCC). FAK and Src protein expression was assessed immunohistochemically on 48 mobile tongue SCC tissue samples and was analyzed in relation with clinicopathological characteristics, overall and disease-free patients' survival. FAK positivity was noted in 32 (66.67 %) and Src positivity in 45 (93.75 %) out of 48 mobile tongue SCC cases. FAK and Src protein expression was significantly increased in well-differentiated tumors compared to poorly differentiated ones (p = 0.0455 and p = 0.0301, respectively). Mobile tongue SCC patients presenting elevated Src expression showed longer overall and disease-free survival (log-rank test, p = 0.0145 and p = 0.0388, respectively). In multivariate analysis, the depth of invasion proved to be an independent prognostic factor of both overall and disease-free patients' survival (Cox regression, p = 0.0313 and p = 0.0481, respectively), whereas Src expression did not remain significant. The present study supported evidence for a potential role of FAK and Src signaling in mobile tongue SCC, rendering their small-molecule tyrosine kinase inhibitors as possible treatment strategy in tongue cancer chemoprevention.