Evaluation of Her-2 protein in histologically tumor-free margins of oral squamous cell carcinoma: An immunohistochemical study.

ABSTRACT

Background: The status of the 5-year survival rate and loco-regional recurrence in oral squamous cell carcinoma (OSCC) has remained unchanged over the decades. Recent advances in oral cancer research have revealed that the presence of molecular alterations in histologically tumor-free margins of OSCC has a prognostic significance and can aid in designing therapeutic strategies. However, the literature on molecular studies on histologically tumor-free margins is scant, especially in the Indian population. Considering the prognostic implications of Her-2 in malignancies of the breast, ovary, and OSCC, we aimed to assess the expression of Her-2 protein in histologically tumor-free margins of OSCC and to establish correlation with clinico-pathological parameters. Methods: 4 µ m thick sections from formalin-fixed paraffin-embedded tissue blocks of 40 histologically tumor-free margins of OSCC affecting the buccal mucosa and/or lower gingiva-buccal sulcus and 40 normal oral mucosa samples were subjected to immunohistochemical analysis for the Her-2 antibody. The obtained data were analyzed statistically. Results: The mean ages in study and control groups were 49.83 years (SD ± 10.43) and 37.28 years (SD ± 8.61), respectively, with male predominance. Local recurrence was seen in 52.5% of patients. Follow-up data revealed that a total of 71.4% of patients succumbed to mortality and all of them had reported local recurrence. Overall, the presence of local recurrence and the status of survival showed a statistically significant association (p = 0.0001). All the samples in the study and control groups were negative for Her-2 immuno-expression. Conclusion: The study indicated the lack of Her-2 immuno-expression in histologically tumor-free margins of OSCC with several speculated explanations. As it is a preliminary study, further studies employing both immunohistochemistry (IHC) and gene amplification in histologically tumor-free margins of OSCC affecting different anatomical sites are warranted. This will aid in identifying the subset of patients that may benefit from targeted therapy.