<prompt> A patient of multiple myeloma presents with bony lesions. What is the best marker for prognosis of the disease:Bone marrow plasma cellSerum calcium levelBeta 2 microglobulinBeta 1 microglobulin  <response>: Answer is C b2 microglobulin: Serum b2 microglobulin is the single most powerful predictor of survival and can substitute for staging-H-16th 