A high level of expression of IFI6 has been seen in colorectal cancer, gastric cancer, breast cancer, myeloma, and tongue squamous cell carcinoma; additionally, expression is extremely high in multi-drug resistant cancer cells, suggesting that a close correlation between IFI6 levels and resistance to apoptosis is present [52,53,54]. This evidence concerns the gene IFI6 and tongue squamous cell carcinoma.