The research revealed that RAI2 was down-regulated in most tumors, including bladder urothelial carcinoma (BLCA), stomach adenocarcinoma (STAD), breast invasive carcinoma (BRCA), colon adenocarcinoma (COAD), glioblastoma multiforme (GBM), esophageal carcinoma (ESCA), head and neck squamous cell carcinoma (HNSC), prostate adenocarcinoma (PRAD), among others (Figure 2A). This evidence concerns the gene RAI2 and head and neck squamous cell carcinoma.