Genetic variation in RETN is associated with a greater risk of various diseases, including metabolic syndrome and colon cancer [15, 16], while a functional RETN gene polymorphism at -420 (rs186513) appears to promote susceptibility to type 2 diabetes [17] and RETN SNPs have been found to correlate with lung cancer progression in a Chinese Han population [18]. This evidence concerns the gene RETN and lung cancer.