Scientists at the University at Buffalo, New York, have found a possible link between a variant of the apolipoprotein E (apo E) gene and breast cancer. The gene, which is involved in lipid metabolism, has three variants: apolipoprotein E2, E3, and E4.
The apolipoprotein E4 variant is associated with raised concentrations of cholesterol and triglycerides and with an increased risk of coronary artery disease and Alzheimer’s disease.
The researchers wanted to see whether the apo E genotype affected the association between triglycerides and the risk of breast cancer. They analysed blood samples from 256 women with primary breast cancer and 325 community controls, all from western New York state.
Among the women with one or two copies of the apo E4 gene, those who also had high concentrations of triglycerides had four times the risk of developing breast cancer when compared with women with low triglyceride concentrations, said Dr Jo Freudenheim, an epidemiologist and professor of social and preventive medicine at the University at Buffalo.
Women with high triglyceride concentrations alone had a slightly increased risk of developing breast cancer. Women with the apo E4 gene alone (without high triglyceride concentrations) did not have an increased risk of breast cancer.
The study was presented this week at the meeting of the International Society for Environmental Epidemiology in Athens, Greece, by Dr Kirsten Moysich, a molecular epidemiologist at the University at Buffalo and the Roswell Park Cancer Institute, also in Buffalo. It has been accepted for publication in Molecular Carcinogenesis.
Dr Moysich said: “We think that apo E4 keeps serum triglyceride levels elevated by reducing their clearance. Triglycerides themselves appear to be a risk factor for breast cancer.”