IGFBP4–1 is negatively associated with the expression of the gene coding for insulin-like growth factor binding protein-4 (IGFBP-4), located downstream and associated with tumor differentiation; IGFBPs mediate the effects of the insulin-like growth factors, potent mitogens that control cell proliferation in normal as well as neoplastic lung cells [50]. This evidence concerns the gene IGFBP4 and neoplasm.