AGR2 and head and neck squamous cell carcinoma: In a meta-analysis of gene expression profiling, increased AGR2 DNA copy number of mRNA expression was significantly increased in many cancers (e.g., esophagus, thyroid, ovarian, pancreatic, breast, prostate, lung, and HNSCC) compared with the normal counterpart (P < 0.001, Supplementary Fig. 1), thereby suggesting that AGR2 may act as an oncogene in human cancer cells.