[Expression and Clinical Significance of NAMPT in Bone Marrow of Patients with Multiple Myeloma].

OBJECTIVE: To study the expression level of nicotinamide phosphoribosyltransferase (NAMPT) in multiple myeloma (MM), its relationship with clinical indicators, prognosis and potential role. METHODS: Immunohistochemical staining was used to detect the expression of NAMPT in bone marrow biopsies of patients with newly diagnosed multiple myeloma (NDMM) and patients with iron deficiency anemia (IDA) hospitalized during the same period. According to the median expression level of NAMPT, NDMM patients were divided into high expression group and low expression group. The correlation between NAMPT expression level and clinical baseline data was analyzed, and survival analysis was performed to evaluate the relationship between NAMPT expression level and prognosis. The GSE24080 and GSE19784 datasets were used to analyze the effect of NAMPT on the prognosis. Gene set enrichment analysis (GSEA) explored the possible mechanism of NAMPT involved in MM cell function. RESULTS: The mean staining intensity of NAMPT in bone marrow tissue of 31 NDMM patients was 0.007±0.002, and that of 10 IDA patients was 0.002±0.002 (P < 0.05). The median expression level of NAMPT was 0.0041 in NDMM patients, and the mean staining intensity of high expression group and low expression group was 0.007±0.005 and 0.002±0.001, respectively (P < 0.001). There were certain differences in lactate dehydrogenase (LDH), C-reactive protein (CRP) and ISS staging between high expression group and low expression group (P < 0.001), while no significant differences in other indicators. The overall response rate (ORR) of high expression group was significantly lower than that of low expression group (P < 0.001). The median survival time of patients in high expression group was significantly shorter than that in low expression group (P =0.024). The results of bioinformatics analysis showed that the event-free survival (EFS) rate and overall survival (OS) rate of low NAMPT group were both higher than high NAMPT group (P =0.037, P =0.009), and NAMPT was an independent prognostic factor for EFS and OS (P =0.006, P =0.020). GSEA suggested that NAMPT might affect MM cell function through mTORC1 signaling pathway. CONCLUSIONS: The expression level of NAMPT in bone marrow of NDMM patients is significantly higher than that of IDA patients, and the high expression of NAMPT may be correlated with late ISS stage, and high level of LDH and CRP. Patients with high expression of NAMPT have worse response to bortezomib and survival time may be shorter. NAMPT may be involved in the occurrence and development of MM through mTORC1 signaling pathway.