ERBB2 and neoplasm: Extracted demographic variables include participant’s date of birth and date of diagnosis, tumour characteristics including tumour stage, tumour size (millimetre), tumour grade and histological type, estrogen receptor status, progesterone receptor status, human epidermal growth factor receptor 2 status, treatment-related variables including surgery, radiotherapy, adjuvant chemotherapy, neo-adjuvant chemotherapy, endocrine therapy, and targeted therapy.