Current epidemiological evidence suggests an association between obesity, hyperinsulinemia, and colorectal cancer risk.
Adiponectin is a hormone secreted by the adipose tissue, and serum levels are inversely correlated with obesity and hyperinsulinemia.
While there is evidence of an association between circulating adiponectin levels and colorectal cancer risk, no association between genes of the adiponectin pathway and colorectal cancer have been reported to date.
Dr Virginia Kaklamani and colleagues from the USA determined the association of 10 haplotype-tagging single-nucleotide polymorphisms of the adiponectin and adiponectin receptor 1 genes with colorectal cancer risk.
The team recruited 2 case-control studies including patients with a diagnosis of colorectal cancer and controls between 2000 and 2007.
|Adiponectin single nucleotide polymorphisms rs822395 was associated with colorectal cancer risk|
|Journal of the American Medical Association|
Case-control study 1 included a total of 441 patients with a diagnosis of colorectal cancer and 658 controls.
Both groups were of Ashkenazi Jewish ancestry and from New York.
Case-control study 2 included 199 patients with a diagnosis of colorectal cancer and 199 controls from Chicago, Illinois, matched 1 to 1 for sex, age, and ethnicity.
The team evaluated adiponectin and adiponectin receptor 1 single-nucleotide polymorphisms frequency among cases and controls.
In study 1, after adjustment for age, sex, and single-nucleotide polymorphisms from the same gene, 3 adiponectin single-nucleotide polymorphisms and 1 adiponectin receptor 1 single-nucleotide polymorphism were associated with colorectal cancer risk.
The research team noted that the adiponectin single-nucleotide polymorphisms rs266729 and rs822396 were associated with decreased risk.
However, adiponectin single nucleotide polymorphisms rs822395 and rs1342387 were associated with increased risk of colorectal cancer.
In study 2, after adjustment for age, sex, race, and single-nucleotide polymorphisms from the same gene, the adiponectin single-nucleotide polymorphism rs266729 was associated with a decreased colorectal cancer risk of similar magnitude as in study 1.
Combined analysis of both studies shows an association of rs266729 with decreased colorectal cancer risk.
Dr Kaklamani’s team concluded, “The single-nucleotide polymorphism rs266729, which tags the 5' flanking region of the adiponectin gene, is associated with decreased colorectal cancer risk.”