Evaluation of Epidermal Growth Factor Receptor and Its Inducible Feedback Inhibitor Leucine Rich Repeats and Immunoglobulin Like Domains 1 as Prognostic Marker in Oral Cancer

Oral squamous cell carcinoma (OSCC) is a life-threatening disease that ranks sixth amongst the most common human cancers worldwide. In most cases, OSCC development is preceded by oral premalignant disorders (OPMDs). There is an urgent need for more biomarker studies that will aid in early detection, diagnosis, and treatment of OPMD to prevent their transformation to OSCC. Leucine rich repeats and immunoglobulin like domains 1 (LRIG1) are known to negatively regulate EGFR expression. Little is known about the significance of LRIG1 in oral cancer pathogenesis. In a retrospective study, immunohistochemical analysis of EGFR and LRIG1 was carried out in 212 archival oral tissues (100 OSCC, 87 OPMD, and 25 normal), correlated with clinicopathological parameters and disease outcome over 62 months for OSCC patients. Further, gene expression for EGFR and LRIG1 was also evaluated in 160 tissue samples. Significant increase in EGFR in OSCC tissue was observed compared to controls, while LRIG1 levels were found to be downregulated in OSCC and OPMD cases compared to normal tissues (p < 0.05). Kaplan-Meier analysis of patients stratified to high and low LRIG1 expression showed significantly different overall survival (p < 0.05, median survival 1397 and 561 days, respectively). A unique translational impact of our study is that it provides clinical evidence for the potential of LRIG1 downregulation as predictor of poor prognosis in OSCC. These preliminary findings support further research to validate LRIG1 based prognostic tools for oral cancers.