Breast cancer in relation to childhood parental divorce and early adult psychiatric disorder in a British birth cohort

Abstract

Background Epidemiological studies have shown that only about 20% of the familial clustering of breast cancer is explained by the known highly penetrant mutations in BRCA1 and BCRA2. We have set out to search for the genes for the remaining 80%. Twin studies indicate a predominant role of shared genes rather than a shared environment; the patterns of occurrence of breast cancer in families are consistent with a major polygenic component. Methods We have assembled a population based set of 5,000 breast cancer cases and 5,000 controls from the East Anglian population. We have simple clinical and epidemiological information, including family history, and samples of blood and paraffin embedded tumour. We have used association studies based on single nucleotide polymorphisms, first with candidate genes and then in a genome-wide scan of 266,000 single nucleotide polymorphisms, to search for the putative predisposing genes. We have as yet searched only for common variants (frequency >5%).