This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pathology
[{'content': 'ER-positive status in Ca Breast indicates - \nSelect and explain. \nA. Prognosis, B. Etiology, C. Site, D. None', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Estrogen receptor (ER) positive breast carcinomas are generally slow-growing and respond well to hormonal treatment.\nGene expression profiling, which can measure the relative quantities of mRNA for essentially every gene, has identified five major patterns of gene expression in invasive ductal carcinoma.\n\n1. Luminal A\n\nThis is the largest group (40-55%) which has characteristics of normal luminal cells.\nThis type is ER-positive and HER2/neu negative.\nThese cancers are generally slow-growing and respond to hormonal treatment. Conversely, only a small number will respond to standard chemotherapy\n\n2. Luminal B\n\nThese tumors are ER positive, has a higher proliferative rate and overexpresses HER2/neu →\xa0Triple - positive cancer.\nThey comprise a major group of ER-positive cancers that are more likely to have lymphnode metastases and may respond to standard chemotherapy.\n\n3. Normal breast line\n\nThese are ER-positive, HER2/neu negative and characterized by the similarity of their gene expression pattern to normal tissue.\n\n4. Basal line\n\nThese are ER negative, PR negative, HER2/neu negative →\xa0Triple negative.\nThese are characterized by expression of markers typical of myoepithelial cells (e.g., basal keratins, P-codherins, p6.3, or laminin), progenitor cells, or putative stem cells (e.g. cytokeratins 5 and 6).\nMany carcinomas arising in women with BRAC 1 mutations are of this type.\nThese are aggressive tumors, frequent metastasis to viscera and brain can be seen → have a poor prognosis.\n\n5. HER2 positive\n\nThese are ER-negative and overexpress HER 2/neu protein.', 'role': 'assistant'}]