Objective: To investigate the expression of Notch1 on the membrane of bone marrow CD38(+)CD138(+) plasma cells in the patients with multiple myeloma (MM), and explore the importance of Notch signaling pathway in the formation and progression of MM.
Methods: Thirty three MM patients and 15 healthy controls were enrolled in this study. The expression of Notch1 on the membrane of bone marrow CD38(+)CD138(+) and CD38(+)CD138(-) plasma cells were analyzed by flow cytometry. The clinical data of MM patients were also analyzed.
Results: The ratio of Notch1 on the membrane of CD38(+)CD138(+) plasma cells of MM patients was (60.21 ± 25.06)% which was significantly higher than those of CD38(+)CD138(-) plasma cells of MM patients (39.84 ± 18.94)% (P = 0.000) and controls (38.34 ± 19.39)% (P = 0.004). There was no statistical difference between the two latter groups (P > 0.05). The expression of Notch1 on CD38(+)CD138(+)plasma cells from 24 newly diagnosed MM patients was correlated to the level of malignant plasma cells in there bone marrow (r = 0.914, P = 0.000), serum level of lactate dehydrogenase (LDH) (r = 0.754, P = 0.007), and β(2)-MG(r = 0.716, P = 0.013). The ratio of Notch1 on the membrane of CD38(+)CD138(+) plasma cells of MM patients who had renal dysfunction was correlated to their abnormal serum creatinine levels. The expression of Notch1 on CD38(+)CD138(+) plasma cells from 17 MM patients who received VD (bortezamib and dexamethasone) chemotherapy was correlated to the ratio of plasma cell reduction after the first VD chemotherapy (r = 0.842, P = 0.000).
Conclusion: The expression of Notch1 on the membrane of CD38(+)CD138(+) plasma cells of MM patients was significantly higher than those of CD38(+)CD138(-) plasma cells of MM patients and controls. Notch1 overexpressed plasma cells were sensitive to the early VD therapy, and correlated to the progression and long term outcome of MM.