The causes of cancer are complex and not fully known.However, we do know that having a family history of breast, ovarian or a related cancer can significantly increase the risk of developing breast cancer - including developing the cancer at a younger age.
It is also more likely that people with family members affected by cancer who then develop breast cancer themselves could develop a separate tumour in the other breast following initial treatment.
This is why it's wise for any person with a family history of cancer to receive appropriate investigations and screening that would otherwise be unnecessary if a family history did not exist.This guideline was last updated in 2006. Since then there has been new evidence published and new advances made in a number of clinical areas
More top news
Adverts featuring blind footballers kicking a cat and a twerking businessman were among the most complained-about commercials of 2016.
No energy supplier scored highly enough to be awarded the Which? recommended provider status.
ITV said the move was to "focus our efforts on our digital platforms, in support of the main show."