Breast cancer is different in each patient and therefore physicians strive to set up a treatment plan that is tailored to each patients individual situation. In most cases, surgical removal of the tumor is a critical step in the treatment of breast cancer. The next step can be additional therapy to minimize the chance of any remaining tumor spreading (metastasizing). In many cases it is very difficult to determine whether an individual patient has a high or low risk that her cancer will spread to other sites.

Dr. Laura van´t Veer and Prof. dr. René Bernards, cancer scientists from the Netherlands Cancer Institute in Amsterdam, together with their colleagues, have compared the genomic tumor profiles of a large number of women suffering from breast cancer. They identified a set of 70 genes that are crucial in predicting the likelihood of breast cancer recurrence after a woman's initial cancer treatment. These findings have been validated in large, international follow-up studies.