SIRT6 and cancer: An increasing number of studies report that SIRT6 expression is significantly associated with both solid and hematological human cancer types such as head and neck squamous cell carcinoma [80], HCC [55,81,82,83], prostate cancer [84], breast cancer [85], skin squamous cell carcinoma (SCC) [45,86], melanoma [87,88,89,90], diffuse large B-cell lymphoma (DLBCL) [91], and acute myeloid leukemia (AML) [92] highlighting its role in tumorigenesis as tumor promoter.