Elevated inflammatory markers are associated with poor outcomes in various types of cancers; however, their clinical significance in multiple myeloma (MM) have seldom been explored. This study investigated the prognostic relevance of neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and monocyte-to-lymphocyte ratio (MLR) in MM. Totally 559 MM patients were included in this study. NLR, PLR and MLR were calculated from whole blood counts prior to therapy. Kaplan-Meier curves and multivariate Cox proportional models were used for the evaluation of the survival. It has shown that newly diagnosed MM patients were characterized by high NLR and MLR. Elevated NLR and MLR and decreased PLR were associated with unfavorable clinicobiological features. Applying cut-offs of 4 (NLR), 100 (PLR) and 0.3 (MLR), elevated NLR, MLR and decreased PLR showed a negative impact on outcome. Importantly, elevated NLR and decreased PLR were independent prognostic factors for progression-free survival. Thus, elevated NLR and MLR, and decreased PLR predict poor clinical outcome in MM patients and may serve as the cost-effective and readily available prognostic biomarkers.

Despite unsurpassed anti-tumor activity of bortezomib for multiple myeloma (MM), drug resistance has emerged as a challenge, especially when MM cells adhere to the stroma. This study aimed to determine whether bone marrow stromal cells (BMSCs) have a role in the development of chemoresistance in MM. Our data demonstrate that the secretion of interleukin-6 (IL-6), vascular endothelial growth factor (VEGF), and cell-to-cell contact with microenvironment-derived stromal cells from patients with multiple myeloma (MM-BMSCs) significantly decreased the sensitivity of myeloma cells to bortezomib treatment. Mechanistically, we found that microRNA (miRNA)- 15a expression was up-regulated in U266 and NCI-H929 cells treated by bortezomib, which was inhibited by MM-BMSCs. miRNA-15a transfected myeloma cells were arrested in G1/S checkpoint and secreted less VEGF compared to control transfected cells, although no significant difference was found in VEGF mRNA levels. In conclusion, our data suggest that via suppressing miRNA-15a expression, BMSCs provide survival support and protect myeloma cells from bortezomib induced apoptosis.

Ibrutinib (Imbruvica®), a small-drug inhibitor of Bruton tyrosine kinase (BTK), is currently undergoing clinical testing in patients with multiple myeloma (MM), yet important questions on the role of BTK in myeloma biology and treatment are outstanding. Using flow-sorted side population (SP) cells from human myeloma cell lines (HMCLs) and MM primary samples as surrogate fort the elusive multiple myeloma stem cell (MMSC), we found that elevated expression of BTK in myeloma cells leads to AKT/WNT/β-catenin-dependent up-regulation of key stemness genes (OCT4, SOX2, NANOG, MYC) and enhanced self-renewal. Enforced transgenic expression of BTK in myeloma cells increased features of cancer stemness, including clonogenicity and resistance to widely used myeloma drugs, whereas inducible knockdown of BTK abolished them. Furthermore, over-expression of BTK in myeloma cells promoted tumor growth in laboratory mice and rendered SP-derived tumors that contained high levels of BTK more sensitive to the selective, second-generation BTK inhibitor, CGI1746, than SP-derived tumors that harbored low levels of BTK. Taken together, these findings implicate BTK as a positive regulator of myeloma stemness and provide additional support for the clinical testing of BTK-targeted therapies in patients with myeloma.

The common features shared by primary plasma cell leukemia (pPCL) and multiple myeloma (MM) with circulating plasma cells (CPCs) are peripheral blood invasion and expansion of plasma cells independent of the protective bone marrow (BM) microenvironment niche. However, few studies have addressed the relationship between pPCL and MM with CPCs. Here, we quantitated the number CPCs by conventional morphology in 767 patients with newly diagnosed MM; their clinic features were compared with those of 33 pPCL cases. When the presence of CPCs was defined as more than 2 % plasma cells per 100 nucleated cells on Wright-Giemsa stained peripheral blood smears, the incidence of MM with CPCs was 14.1 % in newly diagnosed MM. Patients with CPCs shared many clinical features with pPCL, especially clinical parameters related to tumor burden. However, no commonalities were found in immunophenotyping and cytogenetics. The prognosis of pPCL was poor, with a median progression free survival (PFS) of 12 months and an overall survival (OS) of 15 months. MM patients with CPCs had a clearly inferior PFS and OS as compared with the control cohort. Most interestingly, although the CPCs were not high enough to meet the diagnostic criteria for pPCL, the survival of MM patients with CPCs was comparable with that of pPCL, with a median PFS of 17 months and an OS of 25 months.