ERBB2 and breast cancer: In a phase III HERA trial (24) that included 5102 HER2-positive early-stage breast cancers, the group receiving trastuzumab showed a significant reduction in the risk of disease-free survival events and death in comparison with the observation group that did not receive it, with a 24% relative reduction in the risk of DFS events and 26% relative reduction in the risk of death after 1 year of trastuzumab use by patients.