Introduction This study endeavors to evaluate the frequency of programmed death-ligand 1 (PD-L1) expression in oral squamous cell carcinoma (OSCC) specimens and to correlate these findings with clinicopathological features of established prognostic significance. Methodology The study included paired pre-surgical biopsy and resection specimens from 35 patients with OSCC. Immunohistochemistry was performed for PD-L1 (clone SP263) with 51.4% tumor proportion score (TPS) and 77.1% combined proportion score (CPS), which was assessed at a cut-off of ≥1%. The association of the mean expression of the biomarker with clinicopathological parameters has been evaluated. Results TPS of PD-L1 expression at the cut-offs of ≥1%, ≥10%, ≥25%, and ≥50%, and the positivity rates were 20% (7/35), 8.6% (3/35), 8.6% (3/35), and 14.3% (5/35), respectively. The CPS at the same cut-offs were 22.9%, 31.4%, 17.1%, 11.4%, and 17.1%, respectively. TPS was significantly correlated with stage (P = 0.01), while CPS was associated with perineural invasion (P = 0.04) and showed increased expression in the male population (P < 0.05). Conclusions This study highlights the significance of a larger/resection specimen over a small biopsy for PD-L1 evaluation. Increased PD-L1 expression observed in higher-stage disease, perineural invasion (PNI), and male patients can be validated in a larger cohort and potentially guide the use of anti-PD-L1 therapy in OSCC.
Keywords: combined positive score; immunohistochemistry(ihc); oscc; pd-l1 expression; tumor proportion score (tps).
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