RETN and obesity due to melanocortin 4 receptor deficiency: Despite the fact that adipose tissue is a primary source of adipokines and obesity, the condition accompanied with high serum levels of adipokines and related to many malignancies including colorectal cancer (31-34), recent investigation has demonstrated that resistin and visfatin plasma levels are significantly increased in colorectal cancer (CRC) patients independent of BMI and may be good biomarkers for malignant potential and stage progression of this cancer (13, 32).