ERBB2 and breast cancer: PTEN inactivation mutations occur in 9%, 7%, 2%, and 15% of HR+HER2-, HR+HER2+, HR-HER2+, and TNBC breast cancer, respectively, and Akt1 activation mutations occur in 7%, 2%, and 3% of HR+HER2-, HR+HER+, and TNBC breast cancer, respectively [9].