PROM1 and skin squamous cell carcinoma: Although the role of SIRT1 in tumorigenesis remains controversial [30-33], SIRT1 expression was shown to be significantly elevated in a number of human cancers, including acute myeloid leukemia [34], prostate cancer [35], colorectal cancer [36], skin squamous cell carcinoma [37], chemoresistant leukemia [38], and CD133-positive glioblastoma stem cells [39].