This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Endocrinology, Subject name: Medicine
What laboratory test is most appropriate for this patient? 
Select and explain. 
A. Alpha-fetoprotein, B. Beta2-microglobulin, C. Calcitonin, D. Insulin-like growth factor-1
C: Calcitonin
Answer: C: Calcitonin 
Explanation: Answer C. CalcitoninThis patient had multiple flesh-colored papules on the eyelids, lips, and tongue. This phenotype is suggestive of multiple endocrine neoplasia (MEN) type 2B (MEN-2B), an autosomal dominant condition characterized by medullary thyroid cancer among other features. Serum calcitonin can be used to screen for medullary thyroid cancer.