This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Haematology, Subject name: Anatomy
Beta 2 microglobulin is a tumour marker for: 
Select and explain. 
A. Multiple myeloma, B. Lung cancer, C. Colonic neoplasm, D. Choriocarcinoma
A: Multiple myeloma
Answer: A: Multiple myeloma 
Explanation: Increased levels of microglobulin are seen in the urine and serum of patients with multiple myeloma. Serum beta 2 microglobulin is the single most powerful predictor of survival and can substitute for staging. (ref Harsh mohan 6th/383,Robbins 9th/)