B2M and hypercalcemia disease: Median hemoglobin level was 12.1 g/dL, median creatinine and estimated creatinine glomerular filtration (eGFR) were 0.9 mg/dL and 76.7 mL/min, respectively, beta-2 microglobulin was greater or equal to 5.5 mg/L in 36 (17.4%) patients, and serum calcium was greater or equal to 11 mg/dL in 3 (1.4%) patients; in two patients having biochemical relapse, serum calcium was 11.0 and 11.2 mg/dL respectively for reasons not related to MM, still lower than 11.5 mg/dL which is required for symptomatic hypercalcemia, according to the definition of clinical relapse.