The breast cancer gene BRCA1 interacts with the immune system, preventing it from detecting cancer cells.

Women who have a faulty copy of the gene BRCA1 run a 65 to 85 per cent chance of developing breast cancer. They are also more likely to get ovarian cancer. We already know that the normal version of BRCA1 helps repair gene damage but that alone does not seem enough to explain the harmful effect of the mutation.

Working with a technique called microarray technology, that allows analysis of thousands of genes at once, researchers at Queen's University, Belfast, have found that BRCA1 has a second role. It interacts with a molecule called interferon gamma, the 'watchdog' of the immune system. When BRCA1 is damaged, the surveillance of the immune system - which detects cancer cells and makes them self destruct - is turned off. But the researchers showed that the watchdog role could be restored, by adding a healthy copy of BRCA1 to cells from breast tumours. These experiments bring us a step further in understanding the vital role genes play in breast cancer.

Source

Journal of Biological Chemistry September 2002