With the multivariable analysis, low elasticity (both E-mean and E-max) was an independent factor for breast pCR in HR+HER2- breast cancer (E-mean—adjusted OR: 0.333, 95% CI: 0.120–0.926, p = 0.035; E-max—adjusted OR: 0.322, 95% CI: 0.116–0.893, p = 0.030). The gene discussed is ERBB2; the disease is breast carcinoma.