PDCD1 and non-small cell lung carcinoma: In silico expression analysis using GEPIA2, TNMplot, and UALCAN revealed significantly elevated expression of EGFR, ALK, and KRAS in NSCLC tissues versus normal lung tissues (p < 0.01), while PDCD1 was selectively upregulated in tumors with high immune infiltration, consistent with its immunomodulatory function (29, 30).