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
All of the following are tumor markers, except 
Select and explain. 
A. CEA, B. HCG, C. Alpha-fetoprotein, D. Beta-2 macroglobulin
D: Beta-2 macroglobulin
Answer: D: Beta-2 macroglobulin 
Explanation: Beta-2 microglobulin and not beta macroglobulin may be used as a tumor marker (as in multiple myeloma).