Abstract 1762: Body mass index shows etiologic heterogeneity for risk of diffuse large B-cell lymphoma (DLBCL) subtype defined by cell-of-origin
Authors: Breitenstein Matthew K. , O’Byrne Megan M. , Feldman Andrew L. , Thompson Carrie A. , Macon William R. , Nowakowski Grzegorz S. , Ansell Stephen M. , Slager Susan L. , Habermann Thomas M. , Cerhan James R. 
Published: July 2016

Abstract
Background. DLBCL is the most common non-Hodgkin lymphoma (NHL) subtype in western countries and is known to be clinically heterogeneous. Gene expression profiling has identified two major, biologically distinctive DLBCL subtypes on the basis of their cell-of-origin (COO): the germinal center B-cell (GCB) - characterized by BCL2 rearrangement and C-REL amplification, and activated B-cell (ABC) - characterized by constitutive activation of the NF-kB pathway. Recently, the InterLymph Subtypes Project identified medical history, lifestyle, and family history risk factors for DLBCL using a large pooled analysis of case-control studies. In this study we evaluated these same risk factors for etiologic heterogeneity as defined by DLBCL COO.
Methods. For this analysis we used a clinic-based study of newly diagnosed NHL cases and frequency matched controls, enrolled from 2002-2012, with 474 DLBCL cases and 2203 controls. COO was determined clinically using the Hans algorithm, which is based on immunohistochemistry markers using formalin-fixed, paraffin-embedded tumor tissue. Amongst DLBCL cases 107 were ABC, 207 were GCB, and 160 were missing subtype (tissue unavailable). Risk factor data, including body mass index (BMI), smoking, alcohol use, any allergy, asthma, blood transfusion, diabetes, rheumatoid arthritis, sun exposure, lived on a farm and family history of hematologic malignancy, were collected from self-administered questionnaires. Polytomous logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals for ABC and GCB subtypes, adjusted for age and sex.
Results. The mean age of cases was 60.4 years with 53% male; the mean age of controls was 61.6 years and 53% male. We identified a strong positive association for BMI with risk of ABC but not GBC DLBCL (p-heterogeneity 0.025). Compared to BMI 18.5-24.9 kg/m2, those with a BMI of 25.0-29.9 (OR = 1.65; 0.93-2.93) or 30+ (OR = 2.61; 1.48-4.62) were at increased risk of ABC DLBCL. There was no association for a BMI of 25.0-29.9 (OR = 0.91; 0.63-1.31) or 30+ (OR = 1.21; 0.83-1.76) with GCB DLBCL. There was no evidence of significant heterogeneity between ABC and GCB DLBCL for the other risk factors that we evaluated. Further adjustment of the BMI association for educational level, smoking, and alcohol only slightly attenuated these findings.
Conclusions. We observed a strong positive association of BMI with ABC but not GCB DLBCL. In contrast, other evaluated risk factors showed no heterogeneity by COO. While BMI has not been clearly associated with NHL overall, there has been evidence for an association with DLBCL. The etiologic heterogeneity we observed for ABC DLBCL is notable as BMI is also a strong risk factor for multiple myeloma, another post-germinal center B-cell malignancy. While requiring replication, our findings suggest BMI may influence B-cell neoplasia through effect on post-germinal center pathways.
Citation Format: Matthew K. Breitenstein, Megan M. O’Byrne, Andrew L. Feldman, Carrie A. Thompson, William R. Macon, Grzegorz S. Nowakowski, Stephen M. Ansell, Susan L. Slager, Thomas M. Habermann, James R. Cerhan. Body mass index shows etiologic heterogeneity for risk of diffuse large B-cell lymphoma (DLBCL) subtype defined by cell-of-origin. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1762.