On Wednesday, researchers revealed they found the levels of six proteins in people's blood changed before they were diagnosed with breast cancer.

They claimed this could form the basis of blood testing to catch the disease early in those who are genetically predisposed or have a family history of breast cancer, and catching the disease early means a reduced chance of death.

According to the American Cancer Society, the 5-year relative survival rate for breast cancer detected early is just about 99%, but if the cancer is detected late and spreads beyond the breast tissues, that rate falls by about 10%.

These new results came from the "Trial Early Serum Test" Breast, or TESTBREAST, cancer study initiated in 2011.

Currently the study includes 1,174 women who are at high risk of breast cancer because of a family history or carrying gene variants known to raise breast cancer risk.

Women taking part in the study have given blood samples at least once a year for ten years, when they go for a screening. If they develop breast cancer they give samples when they are diagnosed too.

A team from Leiden University made detailed analyses of 30 blood samples from three women who were diagnosed with breast cancer and three who had not.