Clinicopathological correlation of Tumor Infiltrating Lymphocytes and immune markers in Oral Squamous Cell Carcinoma

In India, around 77,000 new cases and 52,000 deaths are reported annually, which is approximately one-fourth of global incidences. The biological factors that underlie the locoregional and distant spreading of these neoplasms are not completely understood.

Oral squamous cell carcinoma (OSCC) is an immunosuppressive disease able to evade immune surveillance avoiding an effective immune response. The tumor microenvironment (TME) refers to the cellular environment in which tumor cells exist. This is the scenario where tumor-infiltrating lymphocytes (TILs) may play a role in the development of OSCC. A better understanding of TILs as clinically relevant biomarkers in OSCC can also be useful in the selection of patients who would best benefit from intensive adjuvant therapy.

Cluster of differentiation (CD)73, is a glycosyl-phosphatidylinositol anchored cell surface enzyme and has both enzymatic and non-enzymatic functions. Both the enzymatic and non-enzymatic functions of CD73 are involved in the processes of cancer occurrence and development. However, there is almost no information available regarding the influence of CD73 expression on tumor cells in patients with OSCC.

The cytotoxic T-lymphocyte–associated antigen 4 (CTLA 4) and programmed death 1 (PD-1) immune checkpoints are negative regulators of T-cell immune function. Inhibition of these targets, resulting in increased activation of the immune system, has led to new immunotherapies for melanoma, non–small cell lung cancer, and other cancers.

This study aims to assess the TILs and immunohistochemical expression of CD73 lymphocytes and checkpoint molecules CTLA4 and PD-L1 in squamous cell carcinomas of the oral cavity and their possible associations with different histopathological and clinical variables in a patient cohort with OSCC from a single institution.

Novelty and impact of study

Studies evaluating correlation between the immunomarkers expression and other clinical characteristics in HNSCC are to date relatively rare, with inconsistent results. This study uniquely investigates the co-expression and correlation of CD73, CTLA4 and PD-L1 in oral squamous cell carcinoma (OSCC), a topic that remains underexplored, especially in the Indian subcontinent. While each has been studied individually, limited research has evaluated their synergistic role in modulating the tumor immune microenvironment in OSCC. By analyzing their expression patterns and associations with clinicopathological features and immune infiltrates, this study aims to elucidate potential mechanisms of immune escape in OSCC, identify co-targetable immune suppressive pathways and provide a rationale for combined immunotherapeutic strategies targeting CD73, CTLA4 and PD-L1.

Methods

Subjects satisfying the inclusion criteria will be included in the study. Purpose of the study and its significance will be explained to the subjects & then written informed consent will be taken from each subject (consent form attached). After taking their written consent each subject will undergo physical and clinical examination at the time of registration by registered medical practitioner. After appropriate screening and baseline & clinical assessments, subjects will be enrolled in the study

Participant’s Socio-demographic data (such as age, sex, education, economic status, marital status) & risk factors (details of their habits especially the use of tobacco in various forms, alcohol consumption and smoking) will also be recorded in a study proforma (proforma attached). After the subject undergoes surgical treatment for OSCC, the specimen will be sent to the Department of Pathology for histopathological examinationand tissue blocks will be sent to Dr. B.Lal Pathology lab for immunohistochemical evaluation of CD73, CTLA4 and PD-L1. Results will be recorded in MS excel and subjected to appropriate statistical analysis.