In another independent study designed to test the ability of the HER2DX assay to predict the likelihood of pCR in patients with early-stage HER2-positive breast cancer who are receiving a de-escalated neoadjuvant therapy, pretreatment tumor biopsy samples from 80 of 97 patients enrolled in the single-arm, multicenter, prospective phase 2 DAPHNe clinical trial were used for HER2DX assay. This evidence concerns the gene ERBB2 and breast cancer.