ERBB2 and neoplasm: The 8th edition of the American Joint Committee on Cancer (AJCC) includes two staging systems: (1) the anatomic stage, which includes the characteristics of the primary tumour (T), nodal status (N), and distant metastasis (M), and is then further subdivided into clinical and pathologic anatomic stage, and (2) the prognostic stage, adding tumour grade, HR status, HER2 expression, and multigene panel testing results to the anatomic stage [12].