CCL2 has been shown to enhance tumor growth in various cancers, including prostate (Li et al., 2009), breast (Soria et al., 2008), and lung cancer (Cai et al., 2009), and to be elevated in the lungs of NSCLC patients (Arenberg et al., 2000, Rivas-Fuentes et al., 2015). Here, CCL2 is linked to lung cancer.