Next, we validated our proteomic data by performing immunohistochemical staining for CK19, HMGCS‐1, FAM38H, LGALS7 and ferritin light chain (FTL) in 212 SQCLC and 343 HNSCC tissues (Table 2 and Dataset EV4), which confirmed our proteomic data in that CK19, HMGCS‐1 and FTL were more strongly expressed in SQCLC, as opposed to LGALS7 and FAM83H, both of which showed stronger expression in HNSCC (Figs 3C and D, and EV2B). This evidence concerns the gene KRT19 and head and neck squamous cell carcinoma.