SIRT1 and colorectal carcinoma: First, we identifiedthat the mRNA and protein levels of SIRT1 in CRC tissues was much higher than that of adjacent normal tissues (Fig. 5A, B); and its mRNA expression was elevated, as compared with that in NCM460 cell line, in the four CRC cell lines, of which HCT116 cell line showed the highest expression of SIRT1, while HT29 cell line showed the lowest (Fig. 5C).