Background & Objectives:In OSCC, the presence of regional lymph node metastasis at presentation is the most significant adverse prognostic factor and a major determinant of poor survival. Tumor–infiltrating lymphocytes (TILs) often infiltrate solid malignant tumours and extensive lymphocyte infiltration has been related with a more favourable prognosis in patients with various cancers.OSCC often contain large mononuclear cell infiltrates, comprised mainly of T cells, which could reflect an in situ immune reaction against the malignant OSCC cells.The aim of this retrospective study was to evaluate the expression of Cytotoxic T lymphocyte in OSCC using immunohistochemical marker CD8+(CTLs) and correlate these findings with the status of lymphnode.

Methods:The study was conducted on tissue sections obtained from histopathologically diagnosed cases of OSCC (n=30) retrieved from the archives of Department of Oral and Maxillofacial Pathology. The sample consisted of cases showing lymph node metastasis (n=15) and those without pathologic lymph node involvement (n=15). The sections were evaluated by using immunohistochemical staining technique with marker CD8 for Cytotoxic T lymphocytes.The mean immunoexpression of Cytotoxic T lymphocyte was evaluated and correlated with lymphnode status.

Results:A statistically significant increase in the count of CTLs (CD8+) was observed in lymph node negative pN(–) as compared to lymph node positive cases pN(+) of OSCC.

Interpretation & Conclusion: CTLs (CD8+)are involved in modulating the immune response and can contribute to the dissemination or control of metastatic neoplastic cells.It can be considered that T–cell mediated adaptive immunity plays a key role in anti–tumour immunity.