The Heritability of Breast Cancer among Women in the Nordic Twin Study of Cancer

Abstract

Background: Family history is an established risk factor for breast cancer. Although some important genetic factors have been identified, the extent to which familial risk can be attributed to genetic factors versus common environment remains unclear.Methods: We estimated the familial concordance and heritability of breast cancer among 21,054 monozygotic and 30,939 dizygotic female twin pairs from the Nordic Twin Study of Cancer, the largest twin study of cancer in the world. We accounted for leftcensoring, right-censoring, as well as the competing risk of death.Results: From 1943 through 2010, 3,933 twins were diagnosed with breast cancer. The cumulative lifetime incidence of breast cancer taking competing risk of death into account was 8.1% for both zygosities, although the cumulative risk for twins whose cotwins had breast cancer was 28% among monozygotic and 20%

Cis-eQTL-based trans-ethnic meta-analysis reveals novel genes associated with breast cancer risk

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Blood levels of cadmium and lead in relation to breast cancer risk in three prospective cohorts

“…Breast cancer is the most frequently diagnosed cancer in women, accounting for 25% of diagnoses worldwide, with nearly 50% of the diagnoses occurring in Europe and North America . Evidence from studies of migrants moving from a low‐risk to a high‐risk country and studies of twins suggest nongenetic factors contribute substantially to breast carcinogenesis . Public concerns exist about the health effects of broad, low‐level exposure to environmental pollutants worldwide, yet the role of the environmental pollutants in breast carcinogenesis is poorly understood .…”

Differences in the Rate of in Situ Mammary Gland Development and Other Developmental Endpoints in Three Strains of Female Rat Commonly Used in Mammary Carcinogenesis Studies

“…The World Health Organization estimates that, excluding non-melanoma skin cancers, breast cancer was the most common cancer in women and was second only to lung cancer worldwide (GLOBOCAN 2012). While roughly 30% of breast cancer cases can be linked to established risk factors, including genetics, the remaining 70% are associated with exogenous components such as environmental chemical exposures (Davis et al 1993; Fenton 2006; Moller et al 2015). …”