Breast cancer risks

Abi813

Hi My mother in law had breast cancer aged 39/40. What are the chances of our daughter getting it? Thanks

Ingerp

Most breast cancers are not genetic. It might well be that your daughter only has an average risk.

Salamandra

Your spouse might want to be tested for the common genetic mutations. If your spouse is a woman, she should also start getting mammograms younger. If your spouse were to test positive, that would indicate testing your daughter as well. If not, then that is a good sign your daughter is clear from *known* genetic risk factors.

Abi813

Hi it's my Husband's Mum. My husband has been referred to have genetic counseling/screening in order to see if he has the mutated gene and if clear it will be a big sigh of relief for my daughter...

Beesie

If your mother-in-law had a genetic mutation that predisposed her to breast cancer, then your husband had a 50% chance of inheriting this mutation from his mother. If he did inherit it, then your daughter had a 50% chance of subsequently inheriting this mutation from him. If your husband did not inherit the mutation from his mother, then there is no chance that your daughter could have inherited this risk.

So a 50% chance for your husband, followed by a 50% chance for your daughter, which means there there is a 25% chance that your daughter might have inherited this risk. BUT that's assuming that your MIL had a genetic mutation that caused her breast cancer. In fact only 10% - 15% of breast cancers are caused by genetic mutations. The young age at which your MIL was diagnosed would increase this probability, but even if there's a 50% chance that your MIL carried a breast cancer gene, that calculates to only a 12.5% chance that your daughter might have inherited the gene. (50% X 50% X 50%)

Are there other types of cancer within your MIL's line of the family? Cancers that may be related to some of the more common breast cancer genes include ovarian cancer and prostate cancer, and to a lesser degree, pancreatic cancer, colon cancer and various others. If there are no other cancers within the line of the family, then the odds are pretty good that there is no genetic mutation within the family.