Assessment of Programmed Cell Death Proteins in Oral Squamous Cell Carcinoma

Oral squamous cell carcinoma (OSCC) is a significant health concern in Nigeria and although the prevalence is relatively low compared to other populations, late patient presentation, yet to be clearly defined etiology and inadequate facilities for management result in high mortality rates. Chronic inflammation, which borders on immunological concepts of cancer biology have been proposed as contributory. Seeing that immunology is a 'double-edged sword' that can be manipulated for therapy, it is needful to explore this model in OSCC found in Nigerian patients. We aim to investigate the expression of and relationship between PD-1, PD-L1 and PD-L2 in OSCC. This is important because there are now immunotherapies that target the cell programmed death pathway. Twenty FFPE blocks of OSCC were prepared for immunohistochemistry to Abcam Mouse monoclonal Anti-PD1 antibody, Rabbit monoclonal Anti-PD-L1 antibody and Rabbit Polyclonal Anti-PD-L2. Cytoplasmic/membrane staining was taken as positive for the antibodies. The Sinicrope scoring method was used to evaluate staining intensity and proportion. We found that tumor associated macrophages and neoplastic cells expressed PD1, PD-L1 and PD-L2 in differing proportions, but most of the cases were negative for these antibodies. Our results have shown that immunotherapy may be relevant when considering the management of OSCC patients in Nigeria