Immunohistochemical Analysis of B-Cell Maturation Antigen (BCMA) as a Novel Marker in Correlation with Its Serum Level to Predict Multiple Myeloma Patients' Outcome

Background: Multiple myeloma (MM) is a neoplastic disorder characterized by clonal proliferation of malignant plasma cells in the bone marrow (BM) producing monoclonal proteins and inducing specific organ and tissue damage. This study aimed to evaluate the expression and serum level of B cell maturation antigen (BCMA) and its prognostic value in newly diagnosed multiple myeloma patients. Methods: This prospective study was carried out on 60 patients who were classified into two equal groups including group I (MM patients) which was newly diagnosed as MM and group II (healthy Control) which healthy individuals served as control. Results: There was a statistically significant increase in MM patients than control group levels were increased in MM patients. Plasma cell percentage in BM aspiration was a statistically significant increase in MM patients. As regarding serum BCMA, there was a statistically significant increase in MM patients than the control group. There was a significantly positive correlation between serum BCMA and its surface expression with plasma cells in BM, CD138 expression in a biopsy, creatinine, B2 microglobulin, LDH, ESR, and total calcium. There was no correlation between BCMA level and age, hemoglobin, WBCs, and platelets count. Serum BCMA and BCMA expression showed a significant correlation with the clinical status of the patients' group, patients with complete response showed a lower level of serum BCMA and lower expression of surface BCMA and longer OS and DFS while patients with failure of CR relapsed group showed a higher level of serum BCMA and higher expression of surface BCMA and shorter OS and DFS. Conclusions: Important role of BCMA expression and its serum level in the diagnosis of multiple myeloma, as the BCMA level in serum significantly elevated in MM patients compared with the control group. Moreover, serum BCMA level and its surface expression are positively correlated with plasma cell percentage in BM aspirate, CD 138 expression in BM biopsy, M protein, and B2 macroglobulin.