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: Unknown
[{'content': 'Which of the following tumors would most likely be associated with either hyponatremia or diffuse pigmentation of skin? \nSelect and explain. \nA. Renal adenocarcinoma, B. Small cell carcinoma of the lung, C. Hepatocellular carcinoma, D. Primary squamous cell carcinoma of the lung', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Small cell carcinomas of the lung can ectopically se\xadcrete antidiuretic hormone (ADH) and adrenocortico\xadtropic hormone (ACTH) or ACTH-like peptide to produce hyponatremia and Cushing syndrome, re\xadspectively.\nEctopic production of hormones is one of the para\xadneoplastic syndromes that frequently can predate or accompany cancer. By definition, paraneoplastic syn\xaddromes must be independent of the direct effect of a rumor or its metastasis. Certain tumors derived from non endocrine cells can ectopically produce hormones, examples of which include the small cell carcinoma of the lung producing ADH or ACTH or a primary squamous cancer of the lung producing a parathor\xadmone-like peptide. In the process of normal differenti\xadation, there is suppression of some genes and activation of others. Carcinogenesis, however, often results in mutations that block the suppressor genes resulting in production of products that are not normally made by those cells.\nRenal adenocarcinomas have the potential for ec\xadtopically secreting parathormone-like peptide (hyper\xadcalcemia), gonadotropins (feminization or masculini\xadzation), renin (hypertension), and erythropoietin (secondary polycythemia).\nHepatocellular carcinomas can ectopically secrete erythropoietin (secondary polycythemia) and an insu\xadlin-like peptide (hypoglycemia).', 'role': 'assistant'}]