While miRNAs like miR-21 are frequently upregulated in OSCC and associated with poor prognosis and cancer stem cell properties (Jaksic Karisik et al., 2025), and others like miR-375, miR-92b-3p, and miR-486-5p are downregulated and associated with recurrence (Yan et al., 2017), their direct regulatory impact on PD-1, PD-L1, or CTLA-4 expression in OSCC remains largely uninvestigated. This evidence concerns the gene PDCD1 and cancer.