Estimates of total EBC trastuzumab-related expenditures in the U.S. (~$3.24B USD) are to a first approximation in line with expectations, given the approximate U.S. share of the global breast cancer therapeutics market, HER2 + EBC epidemiology, and global sales figures for Herceptin® (trastuzumab), totaling ~$6B USD in 201927. Here, ERBB2 is linked to breast cancer.