Given the important roles of PAI-1 in multiple biological functions, such as regulation of cell adhesion, detachment and migration, it is biologically plausible that the PAI-1 4G/5G polymorphism may modulate the risk of cancers.Functional studies on this polymorphism have shown that the 4G allele binds only an activator, while the 5G allele binds a repressor as well as an activator, therefore results in reduced transcription of PAI-1[46]. The gene discussed is SERPINE1; the disease is cancer.