Circulating Inflammation Proteins Associated With Lung Cancer in African Americans

Introduction: Lung cancer incidence is higher among African Americans (AAs) compared with European Americans (EAs) in the United States. We and others have previously shown a relationship between immune and inflammation proteins with lung cancer in EAs. Our aim was to investigate the etiologic relationship between inflammation and lung cancer in AAs. Methods: We adopted a two-stage, independent study design (discovery cases, n = 316; control cases, n = 509) (validation cases, n = 399; control cases, n = 400 controls) and measured 30 inflammation proteins in blood using Meso Scale Discovery V- PLEX multiplex assays. Results: We identified and validated 10 proteins associated with lung cancer in AAS, some that were common between EAs and AAs (C-reactive proteins [OR: 2.90; 95% confidence interval (CI): 1.99–4.22], interferon γ [OR: 1.55; 95% CI: 1.10–2.19], interleukin 6 [OR: 6.28; 95% CI: 4.10–9.63], interleukin 8 [OR: 2.76; 95% CI: 1.92–3.98]) and some that are only observed among AAs (interleukin 10 [OR: 1.69; 95% CI: 1.20–2.38], interleukin 15 [OR: 2.83; 95% CI: 1.96–4.07], interferon gamma-induced protein 10 [OR: 1.54; 95% CI: 1.09–2.18], monocyte chemotactic protein-4 [OR: 0.54; 95% CI: 0.38–0.76], macrophage inflammatory protein-1 alpha [OR: 1.57; 95% CI: 1.12–2.21], and tumor necrosis factor β [OR: 0.52; 95% CI: 0.37–0.74]). We did not find evidence that either menthol cigarette smoking or global genetic ancestry drove these population differences. Conclusions: Our results highlight a distinct inflammation profile associated with lung cancer in AAs compared with EAs. These data provide new insight into the etiology of lung cancer in AAs. Further work is needed to understand what drives this relationship with lung cancer and whether these proteins have utility in the setting of early diagnosis.