Hereditary breast ovarian cancer syndrome

Abstract

In South Africa, breast cancer is the most frequently diagnosed cancer among women, with a lifetime risk of 1 in 27.¹ There are many known causes of breast cancer, such as lifestyle choices, genetic predisposition and environmental factors. The majority of breast cancers are sporadic and not caused by inherited mutations (as shown in Figure 1), and only 5% -10% of breast and 10%-15% of ovarian cancers are hereditary.² Hereditary cancer indicates that cancer may result from germline pathogenic variants (mutations) in specific genes, inherited from either parent. Familial cancers (15–20%) are those that appear to have a genetic component, affecting more family members than would be expected by chance alone; however, a single genetic cause or explanation is not known. Familial  cancers may not be linked to a known gene mutation but may be due to a combination of factors shared by a family, including genetic and environmental factors.