ERBB2 and breast cancer: The GPA score for breast cancer incorporates KPS, age, presence of extracranial metastases (ECM), number of brain metastases, and molecular subtypes, including basal, luminal A, human epidermal growth factor receptor 2 (HER2), and luminal B. Median survival times for GPA groups 1 to 4 were 6, 13, 24, and 36 months, respectively, with an overall median of 16 months.