TCGA results revealed a significant increase in the mRNA expression level of GGT5 in various cancers, including esophageal carcinoma (ESCA), glioblastoma multiforme (GBM), head and neck squamous cell carcinoma (HNSC), lung adenocarcinoma (LUAD), prostate adenocarcinoma (PRAD), and stomach adenocarcinoma (STAD) (all p < 0.05). Here, GGT5 is linked to head and neck squamous cell carcinoma.