Adiponectin is mainly secreted by adipocytes8 and is a key hormone responsible for insulin sensitisation.9, 10 While adiponectin protein is abundantly found in the plasma of healthy human subjects,11 adiponectin mRNA levels in the adipose tissue and plasma are dramatically decreased in patients with obesity and/or type 2 diabetes mellitus.12, 13 Because both obesity and type 2 diabetes have been reported to be associated with an elevated risk of colorectal cancer,14–16 we hypothesised that the plasma level of adiponectin may be related to the risk of colorectal cancer. This evidence concerns the gene INS and obesity due to melanocortin 4 receptor deficiency.