Impact of neoadjuvant chemotherapy on PD-L1 expression in oral squamous cell carcinoma: A matched biopsy-resection study. (2025)

[BACKGROUND] Programmed death ligand 1 (PD-L1) is essential for immune evasion and serves as a significant biomarker for immunotherapy in oral squamous cell carcinoma (OSCC). Nevertheless, the changes in its expression after neoadjuvant chemotherapy (NACT) are not well understood. This research sought to assess the variations in PD-L1 expression between matched pretreatment biopsy samples and post-NACT surgical specimens, while also correlating these results with clinicopathological characteristics.

[MATERIALS AND METHODS] The study comprised 130 patients with OSCC, of which 95 were treated with NACT while 35 acted as controls who did not receive NACT. PD-L1 expression was measured via immunohistochemistry (SP263 clone) on pretreatment biopsy samples and corresponding post-NACT resection