The following are multiple choice questions (with answers) about medical knowledge.   **Question:** A 46-year-old man presents to the physician with a complaint of a cough for 6 months. He has been taking over-the-counter cough medications, but they have not helped much. He adds that he expectorated bloody sputum the previous night. He denies breathlessness but mentions that he frequently experiences fatigue after little physical exertion. There is no past history of any specific medical disorder. His father died of lung cancer at the age of 54 years. His temperature is 37.0°C (98.6°F), the pulse rate is 82/min, the blood pressure is 118/80 mm Hg, and the respiratory rate is 18/min. Auscultation of his chest reveals the presence of localized rhonchi over the interscapular region. A plain radiograph of the chest shows a coin-like opacity in the right lung. Further diagnostic evaluation confirms the diagnosis of small cell carcinoma of the lung. If his blood were to be sent for laboratory evaluation, which of the following proteins is most likely to be elevated in his serum?   (A) Bence-Jones protein   (B) Calcitonin   (C) CA 15-3   (D) Neuron-specific enolase
['(D) Neuron-specific enolase <> answer', 'The following are multiple choice questions (with answers) about medical knowledge. <> instruction', '(A) Bence-Jones protein \n (B) Calcitonin \n (C) CA 15-3 \n (D) Neuron-specific enolase <> possible answers', '  A 46-year-old man presents to the physician with a complaint of a cough for 6 months. He has been taking over-the-counter cough medications, but they have not helped much. He adds that he expectorated bloody sputum the previous night. He denies breathlessness but mentions that he frequently experiences fatigue after little physical exertion. There is no past history of any specific medical disorder. His father died of lung cancer at the age of 54 years. His temperature is 37.0°C (98.6°F), the pulse rate is 82/min, the blood pressure is 118/80 mm Hg, and the respiratory rate is 18/min. Auscultation of his chest reveals the presence of localized rhonchi over the interscapular region. A plain radiograph of the chest shows a coin-like opacity in the right lung. Further diagnostic evaluation confirms the diagnosis of small cell carcinoma of the lung. If his blood were to be sent for laboratory evaluation, which of the following proteins is most likely to be elevated in his serum? <> context@']