Genetic, lifestyle factors and HRT increase risk of breast cancer

The risk of breast cancer is increased by genetic and lifestyle factors such as the inherited BRCA2 gene, age of having first child, or use of hormone replacement therapy (HRT). New research published in BioMed Central's open access journal BMC Cancer looked at the relationship between women with breast cancer and diagnosis of cancer in their parents. The results showed that the chances of women with lobular breast cancer having a father with cancer (especially prostate cancer) was almost twice as likely as women with other forms of breast cancer.

Researchers from Lund University looked at the family history, pathology reports and hospital records for women diagnosed with breast cancer between 1980 and 2008. About 40% of the women had invasive ductal breast cancer and 8% had lobular cancer. At diagnosis, 15% of all these women had a father with cancer and 21% had a mother already diagnosed with cancer.

Once the data was adjusted for age, use of HRT, number of children, and known genetic factors, such as having a mother with breast cancer, a woman having a father with cancer almost doubled the risk of having lobular cancer, when compared to any other type of breast cancer.

Since breast cancer is often hormonally driven (in this study 63% of women with lobular cancer were estrogen receptor positive), it might be assumed that the type of cancer the father had could be important. However the increase in risk of lobular breast cancer due to having a father with cancer was independent of both estrogen receptor and progesterone receptor status. Prostate cancer is also often hormonally driven but the link between lobular cancer and a father with cancer remained even after removing the group of fathers with prostate cancer from the analysis.

Carolina Ellberg who performed this research explained, "We also looked at grandparents and other family members, but the increased risk of lobular cancer was directly linked to having a father with cancer. This does not necessarily mean that the daughter of a man diagnosed with cancer is more likely to get lobular breast cancer - it means that if she develops breast cancer it is more likely to be lobular."

Source: BioMed Central