HPRT1 and head and neck squamous cell carcinoma: By intersecting 33 prognostic AMGs in TCGA and 20 prognostic AMGs in GEO, we finally obtained four prognostic AMGs (HPRT1, CTNS, SHMT and SLC38A7) in HNSCC, and the plotted Venn diagram is shown in Supplementary Figure 2E.