Another study, assessing MRI response monitoring during NAC (4 different regimens used, with all HER2-positive cases treated with trastuzumab-based regimens), showed that this represents an accurate tool in TNBC or HER2-positive BC (n = 85), but not in ER-positive/HER2-negative subtype (n = 103) [13]. This evidence concerns the gene ESR1 and breast cancer.