Are mutations in K-RAS, BRAF and PIK3CA genes critical for response to adjuvant trastuzumab treatment in patients with HER-2 positive breast cancer?

Introduction Breast cancer is the most frequent cancer type among Danish women with almost 5000 new cases each year and 1200 deaths [1]. In the last decades the prognosis has, however, improved. Especially, this has been related to the introduction of Human Epidermal Growth Factor Receptor-2 (HER-2) testing, for evaluating the