STUDY: Genetic variations predict breast cancer risk

JOURNAL: Nature Genetics, 4 March 2002

AUTHORS: P D P PHAROAH, A ANTONIOU, M BOBROW, R L ZIMMERN, D F EASTON & B A J PONDER

ABSTRACT: Oral-contraceptive use and family history are among the factors physicians use to identify women who are at higher risk for developing breast cancer. But a woman's genetic makeup is a better predictor, according to a study published online by Nature Genetics.

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COMMENTARY: Genetic risk profiles, which are based on variations in gene sequences between individuals, may provide substantial improvements in identifying women who should take part in disease-prevention programmes.

Breast cancer, similar to many other common diseases, runs in families. Mutation of a few genes, BRCA1 and BRCA2 for example, are associated with high risk of developing cancer, but these account for only a small proportion of all breast cancer cases. Paul Pharoah and colleagues at the Strangeways Research Laboratories in Cambridge, England, looked at the incidence of breast cancer in relatives of cancer patients and determined that, in most cases, predisposition to developing cancer results from mutations in many genes, each of which bestows a small risk. The authors argue that, assuming that all the genes that contribute to breast cancer are found, genetic analysis will be able to identify women with a higher-than-average risk of developing the disease, and that these women should account for 88% of all breast cancer cases.

Even if only half the genes involved are identified, genetic analysis could substantially improve the efficacy of population-based cancer-prevention programmes.