Racial/ethnic disparities in inflammatory gene single‐nucleotide polymorphisms as predictors of a high risk for symptom burden in patients with multiple myeloma 1 year after diagnosis

BACKGROUND This study was conducted to determine whether any regulatory single‐nucleotide polymorphism (SNP) in an inflammatory gene was associated with a high symptom burden in patients 1 year after the diagnosis of multiple myeloma (MM). METHODS MM patients rated symptoms with the MD Anderson Symptom Inventory multiple myeloma module (MDASI‐MM) and provided buccal‐swab DNA samples. SNPs for 4 cytokine genes (interleukin 6 [ IL6 ] −174G>C, IL1β −511C>T, tumor necrosis factor α [ TNFα ] −308G>A, and IL10 −1082G>A) were tested. Logistic regression models were used to identify SNPs that might predict moderate/severe symptoms (rated ≥4 on the MDASI‐MM 0‐10 scale). For the evaluation of the relationship between SNPs and overall symptom burden, a 2‐step cluster analysis was used to divide patients into subgroups with high or low symptom levels. RESULTS Forty‐one percent of the 344 patients enrolled had a high overall symptom burden. The most prevalent moderate/severe symptoms were fatigue (47%), pain (42%), numbness (38%), and bone aches (32%). For non‐Hispanic whites, the IL1β −511 CC genotype was associated with a high overall symptom burden (odds ratio [OR], 2.35; 95% confidence interval [CI], 1.25‐4.72; P  = .004), whereas the IL6 −174 GG genotype predicted less moderate/severe fatigue (OR, 0.53; 95% CI, 0.29‐0.88; P  = .013). For other patients, the IL6 −174 GG genotype predicted moderate/severe pain (OR, 3.36; 95% CI, 1.23‐13.64; P  = .010). CONCLUSIONS These results support growing evidence showing that inflammation is associated with cancer‐related symptoms, and they suggest that racial/ethnic factors contribute to this association. Cancer 2015;121:1138–1146 . © 2014 American Cancer Society .