Indoleamine 2,3-dioxygenase-1 (IDO1) is a promising antitumor target and predictive biomarker in a variety of cancers. Hence, we performed this meta-analysis to evaluate the clinicopathological and prognostic significance of IDO1 in head and neck squamous cell carcinoma (HNSCC).

We searched PubMed, Embase, Web of Science and Scopus databases from inception to May 2024, to identify studies measuring the clinicopathological and prognostic significance of IDO1 in HNSCC. The role of IDO1 in HNSCC was evaluated by pooled hazard ratios (HR), odd ratios (OR) and 95% confidence intervals (CI). The meta-analysis was performed using the meta package in R. Omics analyses on IDO1 were also performed.

Ten studies (1,119 participants) were included in the review. The analysis showed an insignificant relationship between IDO1 expression and poor overall survival, and progression free survival as indicated by the pooled HR (HR: 1.65, 95% CI: 0.68–4.02), (HR: 1.73, 95% CI: 0.63–4.77), respectively. Additionally, elevated expression of IDO1 was significantly associated with tumor T stage (OR: 1.44, 95% CI: 1.06–1.94). However, it was insignificantly correlated with positive lymph node metastasis (N status) (OR: 1.11; 95% CI: 0.82–1.50) and tumor-node-metastasis (TNM) stage (OR: 1.14; 95% CI: 0.79–1.64).

While higher IDO1 expression is associated with the risk of advanced tumor stage in HNSCC, its impact on overall and progression-free survival remains inconclusive. Further research is needed to elucidate its prognostic significance and therapeutic potential.