Anthropometric traits and risk of multiple myeloma: differences by race, sex and diagnostic clinical features.

BACKGROUND: Obesity is an established modifiable risk factor for multiple myeloma (MM). However, associations of obesity and MM risk in Black populations, for whom obesity and MM are more common, is less clear. METHODS: Using participants enrolled in the Integrative Molecular And Genetic Epidemiology study, we evaluated the association of anthropometric traits with MM risk overall, stratified by race and sex. Among cases, we assessed the association of BMI with the presence of myeloma-defining events. RESULTS: We observed an 18% increase in MM risk for every 5 kg/m2 increase in usual adult BMI. Participants with severe obesity (BMI ≥ 40 kg/m2) had the highest risk compared to those with a normal usual adult BMI (18.5-24.9 kg/m2; OR = 1.87, 95% CI 1.25-2.80), particularly among Black men (OR = 3.94, 95% CI 0.90-17.36). Furthermore, MM cases with overweight/obesity (BMI ≥ 25 kg/m2) were more likely to present at diagnosis with low renal function (OR = 1.62, 95% CI 1.09-2.40), deletion 13q (OR = 1.73, 95% CI 1.08-2.76) and lytic lesions or compression fractures (OR = 2.39, 95% CI 0.82-7.01) and less likely to present with severe diffuse osteopenia (OR = 0.51, 95% CI 0.31-0.81). CONCLUSIONS: Findings underscore the importance of obesity as a modifiable risk factor for MM, particularly in high-risk populations, and for the clinical presentation of disease.

Distinct phenotype of neutrophil, monocyte, and eosinophil populations indicates altered myelopoiesis in a subset of patients with multiple myeloma.

Hematologic malignancies, including multiple myeloma (MM), promote systemic immune dysregulation resulting in an alteration and increased plasticity of myeloid cell subsets. To determine the heterogeneity of the myeloid cell compartment in the peripheral blood of patients with MM, we performed a detailed investigation of the phenotype and function of myeloid subpopulations. We report that a subset of MM patients exhibits a specific myeloid cell phenotype indicative of altered myelopoiesis characterized by significant changes in the properties of circulating granulocytic, monocytic, and eosinophilic populations. The subset, referred to as MM2, is defined by a markedly elevated level of CD64 (FcγRI) on the surface of circulating neutrophils. Compared to healthy controls or MM1 patients displaying intermediate levels of CD64, neutrophils from MM2 patients exhibit a less differentiated phenotype, low levels of CD10 and CXC chemokine receptor 2 (CXCR2), increased capacity for the production of mitochondrial reactive oxygen species, and an expansion of CD16neg immature neutrophil subset. Classical and patrolling monocytes from MM2 patients express elevated levels of CD64 and activation markers. MM2 eosinophils display lower levels of C-C Chemokine receptor 3 (CCR3), Toll-like receptor 4 (TLR4, CD284), and tissue factor (TF, CD142). The MM2 (CD64high) phenotype is independent of age, race, sex, and treatment type. Characteristic features of the MM2 (CD64high) phenotype are associated with myeloma-defining events including elevated involved/uninvolved immunoglobulin free light chain (FLC) ratio at diagnosis. Detailed characterization of the altered myeloid phenotype in multiple myeloma will likely facilitate the identification of patients with an increased risk of disease progression and open new avenues for the rational design of novel therapeutic approaches.