LIF and head and neck squamous cell carcinoma: Aberrant overexpression and pro‐tumorigenic functions of LIF were detected across multiple cancers and significantly associated with malignant features and patient survival.[25, 53] Circulating LIF levels positively correlated with tumor burden and immunotherapeutic outcomes, thus underscoring the translational potential as a noninvasive biomarker.[25, 29] Consistent with these pioneering studies, our results confirmed higher LIF transcripts in clinical samples and circulating LIF protein in plasma from HNSCC patients.