TGFB1 and lung adenocarcinoma: TGF-β exerts various functions and its genetic sequence variations are associated with modification of TGF-β production and/or activity, which also affects individual susceptibility to LC; it was observed that people with at least one −509T allele have a decreased risk of lung adenocarcinoma and SCLC, and, at the same time, the 869T > C polymorphism and the combined TC + CC genotype were associated with a decreased risk of SCLC compared with the TT genotype [26].