Abstract
Background: Multiple myeloma (MM) is a clonal late B-cell disorder in which malignant plasma cells expand and accumulate in the bone marrow and is associated with paraprotein production, bone lesions, anemia, hypercalcemia, susceptibility to infections, and renal impaired. Beta-2 microglobulin (B2M) is a serum marker of tumor burden in lymphoid malignancies, including MM. The purpose of this study was to find whether increased B2M levels can predict the progression of MM from asymptomatic to progressed symptomatic phase, as it is a less invasive and cost-effective method than the more invasive and costly ones to predict the progression of the disease.

Aims and Objectives: This study was taken in a medical college, Kolkata, 50 asymptomatic Stage 1 MM patients were taken along with age and gender-matched 50 symptomatic progressed MM patients, blood samples of both groups were evaluated to estimate the difference in serum B2M (SB2M) level in both groups. Moreover, to study the difference in serum albumin, C-reactive protein, creatinine, immunoglobulin (IG), total protein, calcium, hemoglobin, and percentage of plasma cells in both groups and also their correlation with SB2M level in the progressed disease group. As well as to assess if there is increased B2M in the progressed disease group and if the B2M level correlates with the disease severity (i.e. progression of the disease).

Materials and Methods: An observational descriptive non-interventional, hospital-based study conducted at central laboratory, medical college, Kolkata, for 6 months. Patients were chosen by systematic random sampling. Fifty asymptomatic MMs were chosen according to the International Myeloma Working Group criteria and out of 50 patients in the progressed disease group, 75% of patients were in Stage III and 25% of patients were in Stage II according to the Salmon and Durie system.

Results: More than 80% in the progressed and symptomatic group had β-2M >3.5 mg/L. Whereas in the newly diagnosed group, all the 50 patients had their β-2M level <3.5 mg/L. Moreover, B2M value in the blood of progressed MM patients was found to be positively correlated with percentage of plasma cells from bone marrow, serum creatinine level, serum protein level, serum calcium level, and IgG level and negatively correlated with Hb level and serum albumin level. Hence, in a nutshell, increased B2M level was found in the progressed MM group, and its level positively correlated with the other predictors of the progression of MM.

Conclusion: As per this study, SB2M level (which is a less invasive test than bone marrow testing and less costly) can be used as the predictor of progression of MM from asymptomatic to symptomatic. However, small sample size and cross-sectional pattern of the study were the limitations of this study. Bigger sample size and prospective cohort-type study designing method could be a better method to find a stronger correlation between MM staging and SB2M levels.

Key words: Multiple Myeloma; Beta-2 Microglobulin; Prognosis; Biomarker