SIRT1 and neoplasm: In obese CRC patients, serum MEG3 was strongly and positively correlated with anatomical site (r = 0.605, P = 0.0001), serum miR-27a was positively correlated with LN metastasis (r = 0.46, P = 0.012), serum SIRT1 was positively correlated with IGFBP3 (r = 0.45, P = 0.013) and tumor stage (r = 0.584, P = 0.036), while serum IGFBP3 was negatively correlated with LN metastasis (r = − 0.36, P = 0.042).