"The predictive value of family history for identifying persons with at-risk genotypes or environmental risk factors is low," say Temitope O. Keku, Ph.D., of the University of North Carolina at Chapel Hill and colleagues.
However, the researchers also found that people with a family history of colon cancer were as likely as people without a family history to have high-risk diets that included lots of cooked red meat and low amounts of folate, a vitamin that may help prevent colon cancer.
"Modification of these factors could have broad benefits and interventions could be targeted to persons with a family history regardless of their genes," Keku says.
Keku and colleagues analyzed the DNA of 230 black and white adults with a family history of colon cancer, looking for cancer-related variations in four different genes. The researchers also collected information on the study participants' eating habits and their use of nonsteroidal anti-inflammatory drugs like aspirin or ibuprofen, which seem to have a protective effect against colon cancer.
The prevalence of cancer-related variations of a gene called NAT2 was significantly higher among individuals with a family history of colon cancer. Individuals with the NAT2 variant who also reported regular red meat consumption were also more likely to have a family history of colon cancer.
The researchers also found that participants with a family history had a higher prevalence of cancer-related variants of the PPARG gene in combination with low levels of aspirin use.
Despite these findings, family history is a poor predictor of whether an individual has a colon cancer-related gene
Contact: Temitope Keku, Ph.D.
Center for the Advancement of Health