OBJECTIVETo 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.

METHODSThirty 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.

RESULTSThe 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).

CONCLUSIONThe 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.