In addition to the above reasons, the presence of the 4G allele results in a higher PAI-1 transcription response to cytokines or growth factors than the 5G allele, so the 4G/5G polymorphism may influence tissue PAI-1 levels in endometrial cancer patients through the action of cytokines released by tumor cells (25). This evidence concerns the gene SERPINE1 and endometrial cancer.