Family cancer history doesn’t necessarily lead to more healthful living

see Health behaviors and cancer screening among Californians with a family history of cancer

Public health messages about the ways people can reduce their risk of cancer may not be making an impact on those with a family history of the disease, according to a new population-based study reported in this issue. Researchers from the Centers for Disease Control and Prevention used data from the 2005 California Health Interview Survey to examine the relationship between having a first-degree relative with breast or colorectal cancer and receiving recommended screenings as well as following recommended guidelines regarding modifiable lifestyle factors. Among the findings, both men and women with family history of colorectal cancer were actually less likely than those without a family history to maintain a healthy weight and consume the recommended amount of fruits and vegetables. However, those with family history of cancer were more likely to follow guidelines for periodic mammogram or colonoscopy, although many of those with such a history did not receive screenings. The investigators could not assess the reasons behind these behaviors, which would seem to put some individuals at an additional increased risk of cancer, but they suggest that health-care providers counsel patients with family histories of cancer about what they can do to reduce their risk. —Karyn Hede, News Editor

New ACMG Practice Guideline: genetic testing for MTHFR variants rarely warranted

see ACMG Practice Guideline: lack of evidence for MTHFR polymorphism testing

Carrying common genetic polymorphisms in the gene encoding 5,10-methylenetetrahydrofolate reductase (MTHFR) is no longer considered a significant risk factor for abnormal blood clotting, making genetic testing for their presence unnecessary, according to the ACMG. Previous research had suggested that genetic polymorphisms in MTHFR, which are associated with marginal elevations in plasma levels of homocysteine, might increase the risk of venous thromboembolism, coronary heart disease, and recurrent pregnancy loss. But recent meta-analyses have disproven these suspected associations, making MTHFR polymorphism testing minimally useful. Therefore, the ACMG issued a new Practice Guideline, detailed in the February issue, that recommends discontinuation of MTHFR testing as part of a routine evaluation for patients suspected of increased risk of blood clots. Patients who test homozygous for the more common “thermolabile” variant, and who also have normal plasma homocysteine, can now be reassured that they are not at increased risk for venous thromboembolism or recurrent pregnancy loss related to their MTHFR status. In addition, fortification of grain products with folic acid has resulted in higher serum folate concentrations and lower serum total homocysteine levels in general, possibly reducing some of the already low risk of carrying such an MTHFR polymorphism. —Karyn Hede, News Editor