With this issue in mind, the objectives of the current study were to examine the level of access that physicians and patients in the U.S., Mexico (MEX), Turkey (TUR), Russia (RUS) and Brazil (BRZ) have to Herceptin (trastuzumab) and to identify potential barriers that may prevent its use in the treatment of HER2+ breast cancer. This evidence concerns the gene ERBB2 and breast cancer.