[Breast cancer and molecular markers]

Molecular markers have long been studied and used in part as a marker for prediction of prognosis and deciding the treatment for patients with breast cancer. Now development of novel decision-making biomarkers for adjuvant chemotherapy is desired for many patients with hormone receptor-positive early breast cancer. Thanks to recent advances in molecular marker studies on breast cancer, the update committee has systematically reviewed the literature and updated recommendations for the use of tumor markers in breast cancer, one of the ASCO clinical practice guidelines, in 2007. In the revised guideline, gene expression profiling assays are topics in six newly added categories. In this review, the key guideline recommendations and two innovative gene expression profiling assays have been summarized.