WHAT YOU NEED TO KNOW

In the past four decades, the number of new breast cancer cases diagnosed every year has nearly tripled (from 25 to 65 cases for every 100,000 women), while incidences of other cancers have largely remained the same.

More than one breast cancer gene

Many people are familiar with the genes brought to popular attention by actress Angelina Jolie (BRCA1 and BRCA2), but very few people in the general population carry these mutations. Another class of genetic variants is more common (1-50 per cent of the population may carry them). In the past decade, more than 300 new breast cancer risk markers have been found, and these can stratify women into different risk groups.

“Each carries a little increased risk for breast cancer, but with many of them, the effect adds up,” Dr Li explains. “From here, using a summed risk score derived from common breast cancer markers, we can identify women at very high risk of developing breast cancer.

“Combining the knowledge we have gained over the years for rare and common variants, and classical breast cancer risk factor data (age, number of children, hormone use), we have unprecedented precision in identifying women with increased risk of developing breast cancer.”