How does a germline mutation affect my risk of ovarian cancer?

The hereditary cancer susceptibility genes that have been identified in ovarian cancer are highly penetrant, meaning that mutations lead to a risk of developing cancer that is significantly above average. Since cancer is a multi-step process, the presence of a germline mutation (inherited from a parent at the time of conception and present in every cell of the body) makes a person essentially "one step closer" to cancer from the time of birth than the average person, thereby increasing the chance of early-onset cancer and multiple primary cancers.

Although a significant risk factor, a germline mutation does not guarantee that cancer will develop. The likelihood that an individual who inherits a mutation will ultimately develop cancer is dependent on other factors that influence the occurrence of subsequent mutations, such as modifier genes and poorly understood diet, lifestyle and environmental factors.