Molecular Signatures of Breast Cancer — Predicting the Future

Breast cancer affects about 10 percent of women in Western countries and is still a major cause of illness and death. Most patients with lymph-node–negative disease (i.e., with no evidence that cancer cells have spread beyond the primary tumor) can be effectively treated with surgery and local radiation. Patients with more aggressive disease can benefit from adjuvant chemotherapy or hormone therapy and are currently identified according to a combination of criteria1,2: age, the size of the tumor, axillary-node status, the histologic type and pathological grade of cancer, and hormone-receptor status. The ability of these criteria to predict disease . . .