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': 'Uses of tumor marker are -a) Screening of a cancerb) Follow up of a cancer patient, especially for knowing about recurrencec) Confirmation of a diagnosed cancerd) For monitoring the treatment of a cancer \nSelect and explain. \nA. acd, B. abd, C. abc, D. ab', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Tumor markers \n\nSome tumor produce or elicite the production of markers that can be measured in the serum or urine or other body fluids.\nTumor markers are biochemical indicators of the presence of a tumor.\nMarkers may be cell surface antigen, enzymes, hormones, tumor associated protein, or oncofetal antigens.\n\nUses of tumor marker\n\nScreening of cancer.\nTo see the response of therapy → decreasing levels may suggest that tumor is responding to treatment.\nFor follow up → Reappearance of marker may suggest recurrence.\nTo determine the prognosis preoperatively → higher levels suggest high tumor burden.\nTo determine the growth of tumor → increasing levels suggest increase in growth.\nTo support the diagnosis → But, tumor markers are not specific enough to permit a diagnosis.', 'role': 'assistant'}]