ERBB2 and breast cancer: According to the cut-off points of elasticity values, the proportion of a low E-mean and low E-max was as follows: 55.3% (459 of 830) and 56.7% (471 of 830) in all patients (Table S1), 44.2% (114 of 258) and 42.2% (109 of 258) in HR+HER2- breast cancer (Table S2), 60 of 312 (19.2%) and 70 of 312 (22.4%) in HER2+ breast cancer (Table S3), and 146 (56.2%) of 260 and 151 (58.1%) of 260 in TNBC (Table S4), respectively.