Mystery of the missing breast cancer genes

Researchers from the University of Adelaide are hoping to better understand why the mutated genes for breast and ovarian cancer are not passed on more frequently from one generation of women to the next.

That's despite a documented link between breast cancer genes and increased fertility in women.

Dr Jack da Silva from the University's School of Molecular & Biomedical Science says that because women who carry breast cancer genes are more fertile, in theory they have a greater chance of passing these genes on to future generations.

"A recent study in the United States found that mutations in the breast cancer genes BRCA1 and BRCA2 were directly linked with a 50% increase in the fertility of women, which is a huge number," Dr da Silva says.

"With such an increased fertility rate, you would expect to see a high frequency of these cancer-causing genes in modern populations, but in fact that is not the case - the frequencies are relatively low."

In a paper being published today in the Proceedings of the Royal Society B, he argues that the so-called "grandmother effect" may in part be the reason behind this phenomenon.

"In an earlier study, researchers found that post-menopausal women create a 'grandmother effect' - that is, the longer they live, the more they are able to support their daughters and their grandchildren, thereby creating an environment in which more grandchildren are born.

Breast Cancer Myths

Myth: Only women with a family history of breast cancer are at risk. Reality: Roughly 70% of women diagnosed with breast cancer have no identifiable risk factors for the disease. But the family-history risks are these: If a first-degree relative (a parent, sibling, or child) has had or has breast cancer, your risk of developing the disease approximately doubles. Having two first-degree relatives with the disease increases your risk even more.

Wearing an underwire bra increases your risk of getting breast cance

Reality: Claims that underwire bras compress the lymphatic system of the breast, causing toxins to accumulate and cause breast cancer, have been widely debunked as unscientific. The consensus is that neither the type of bra you wear nor the tightness of your underwear or other clothing has any connection to breast cancer risk.

Most breast lumps are cancerous.
Reality: Roughly 80% of lumps in women's breasts are caused by benign (noncancerous) changes, cysts, or other conditions. Doctors encourage women to report any changes at all, however, because catching breast cancer early is so beneficial. Your doctor may recommend a mammogram, ultrasound, or biopsy to determine whether a lump is cancerous.: Surgery doesn't cause breast cancer and it doesn't cause breast cancer to spread, as far as scientists can tell from the research so far.