New role of genes in breast cancer

September 19, 2002

An Australian twin study has uncovered that high breast density, the strongest known risk factor for breast cancer, is genetically linked.

"The hunt is now on to find the genes responsible for breast density," says Professor John Hopper, Director of the University of Melbourne's Centre for Genetic Epidemiology, which houses the Australian Twin Registry.

"Once found, the genes may help define new sub-types of breast cancer, and enable targeted prevention strategies and treatment. It might also explain a greater amount of the genetic effect on breast cancer than do the recently discovered genes BRCA1 and BRCA2," he says.

Australian breast cancer researchers, in collaboration with Canadian colleagues, published the study results in the latest edition of New England Journal of Medicine. The study involved 607 twin pairs from Melbourne, Sydney and Perth, recruited through the Australian Twin Registry, and 355 North American twin pairs.

The research found that in both the Australian and North American twins, genetically-identical twin pairs had similar breast densities. Non-identical pairs, who share half their genes, had breast densities about half as similar.

Breast density is determined by the amount of connective and epithelial tissue - which appears light on a mammogram - compared with amount of fat tissue - which appears dark. It is not related to firmness and cannot be felt in the breast. It is only detectable by having a mammogram.

Women with breast density in the top 20 percent have a five-fold increased risk of breast cancer than women in the bottom 20 percent for their age.

"Although there is evidence that age and some lifestyle factors, such as having children, can change breast density, there is still a large spread in the distribution of breast density across women of the same age," says Hopper.

"This results show that genetic factors play the major role in explaining why women of the same age have different breast density. It also helps explain why having a family history of breast cancer is a risk factor for the disease," says Hopper.

"There may be many genes involved with breast density, and for an individual woman it will be the combined effect of these genes, rather than a single mutation in just one "high-risk" gene like BRCA1 or BRCA2, that determines her risk," he says.

Finding the breast density genes and identifying their mechanisms will help understand the causes of breast cancer.
The Australian research was funded by the National Breast Cancer Foundation and involved researchers from The University of Melbourne, The Cancer Council Victoria, NSW Cancer and St Vincents BreastScreen, Melbourne.

University of Melbourne

Related Breast Cancer Articles from Brightsurf:

Oncotarget: IGF2 expression in breast cancer tumors and in breast cancer cells
The Oncotarget authors propose that methylation of DVDMR represents a novel epigenetic biomarker that determines the levels of IGF2 protein expression in breast cancer.

Breast cancer: AI predicts which pre-malignant breast lesions will progress to advanced cancer
New research at Case Western Reserve University in Cleveland, Ohio, could help better determine which patients diagnosed with the pre-malignant breast cancer commonly as stage 0 are likely to progress to invasive breast cancer and therefore might benefit from additional therapy over and above surgery alone.

Partial breast irradiation effective treatment option for low-risk breast cancer
Partial breast irradiation produces similar long-term survival rates and risk for recurrence compared with whole breast irradiation for many women with low-risk, early stage breast cancer, according to new clinical data from a national clinical trial involving researchers from The Ohio State University Comprehensive Cancer Center - Arthur G.

Breast screening linked to 60 per cent lower risk of breast cancer death in first 10 years
Women who take part in breast screening have a significantly greater benefit from treatments than those who are not screened, according to a study of more than 50,000 women.

More clues revealed in link between normal breast changes and invasive breast cancer
A research team, led by investigators from Georgetown Lombardi Comprehensive Cancer Center, details how a natural and dramatic process -- changes in mammary glands to accommodate breastfeeding -- uses a molecular process believed to contribute to survival of pre-malignant breast cells.

Breast tissue tumor suppressor PTEN: A potential Achilles heel for breast cancer cells
A highly collaborative team of researchers at the Medical University of South Carolina and Ohio State University report in Nature Communications that they have identified a novel pathway for connective tissue PTEN in breast cancer cell response to radiotherapy.

Computers equal radiologists in assessing breast density and associated breast cancer risk
Automated breast-density evaluation was just as accurate in predicting women's risk of breast cancer, found and not found by mammography, as subjective evaluation done by radiologists, in a study led by researchers at UC San Francisco and Mayo Clinic.

Blood test can effectively rule out breast cancer, regardless of breast density
A new study published in PLOS ONE demonstrates that Videssa® Breast, a multi-protein biomarker blood test for breast cancer, is unaffected by breast density and can reliably rule out breast cancer in women with both dense and non-dense breast tissue.

Study shows influence of surgeons on likelihood of removal of healthy breast after breast cancer dia
Attending surgeons can have a strong influence on whether a patient undergoes contralateral prophylactic mastectomy after a diagnosis of breast cancer, according to a study published by JAMA Surgery.

Young breast cancer patients undergoing breast conserving surgery see improved prognosis
A new analysis indicates that breast cancer prognoses have improved over time in young women treated with breast conserving surgery.

Read More: Breast Cancer News and Breast Cancer Current Events is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to