A new study published in the October 1 issue of JAMA reports that decreased colorectal cancer risk is linked to variation of a gene for a protein hormone that is secreted by fat cells.
Previous research has pointed towards a link between colorectal cancer risk and obesity. Serum levels of adiponectin – a hormone secreted by fat tissue – are inversely related with obesity and high levels of insulin. That is lower levels of the hormone are linked to higher levels of obesity and insulin. Virginia G. Kaklamani, M.D., D.Sc. (Feinberg School of Medicine, Northwestern University, Chicago) and colleagues write that, “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.”
In order to investigate the association between variations of the adiponectin (ADIPOQ) and adiponectin receptor 1 (ADIPOR1) genes and colorectal cancer risk, the researchers conducted two case-control studies The studies included patients who were diagnosed with colorectal cancer as well as control patients who did not have a cancer diagnosis. The first case-control study consisted of patients from New York of Ashkenazi Jewish ancestry, 441 with colorectal cancer and 658 controls. The sample in case-control study 2 consisted of patients from Chicago, 199 with colorectal cancer 199 controls who were matched one to one for sex, age, and ethnicity.
Summarizing their results, the researcher write that, “In this clinic-based case-control analysis, we found an association between 1 single-nucleotide polymorphism [SNP; a DNA sequence variation] of the ADIPOQ gene (rs266729) and colorectal cancer risk in 2 separate case-control studies, as well as in the combined analysis of both studies after adjustment for age, sex and other SNPs.”
It may be possible, according to the researchers, that the ADIPOQ gene may harbor SNPs/mutations capable of modifying colorectal cancer risk. “If these exciting results can be confirmed in other studies, the adiponectin axis may emerge as an important modifier of colorectal cancer risk. Future studies will need to address the potential impact of adiponectin and its SNPs in the prognosis of colorectal cancer and also may be incorporated in genetic risk models for the disease,” they conclude.
Variants of the Adiponectin (ADIPOQ) and Adiponectin Receptor 1 (ADIPOR1) Genes and Colorectal Cancer Risk
Virginia G. Kaklamani; Kari B. Wisinski; Maureen Sadim; Cassandra Gulden; Albert Do; Kenneth Offit; John A. Baron; Habibul Ahsan; Christos Mantzoros; Boris Pasche
JAMA (2008); 300[13]: pp. 1523-1531.
Written by: Peter M Crosta