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.