A prospective study conducted by Barrera et al. demonstrated that there are higher levels of IL-6 in the plasma of patients with non-small-cell lung cancer (NSCLC) comparing to controls (p = 0.001) (30), while a retrospective analysis by Ryan et al. also showed IL-6 has a significant association with worse survival (hazard ratio, 1.33; 95% confidence interval, 1.08-1.64; p = 0.007) with hundreds of European American lung cancer patients (31). Here, IL6 is linked to lung cancer.