NFKB1 and chronic obstructive pulmonary disease: Research has further indicated that elevation in plasma miR-133 is positively correlated with nuclear NF-κB p50 in the quadriceps muscle of patients with GOLD I and stage II COPD, and is positively correlated with tumor necrosis factor-α, interleukin 2, and interleukin 5 levels, which may be associated with the inflammatory response in the quadriceps muscle (Donaldson et al., 2013) (Figure 1).