FKBP51 and FKBP52 as potential biomarkers for predicting endometrial receptivity and embryo implantation in assisted reproductive technologies

One of the most important and limiting factors in assisted reproductive technologies (ART) is repeated implantation failure (RIF). In the process of embryo implantation, appropriate function of the progesterone hormone through its receptors is critical for establishment of a receptive endometrium. FKBP51 and FKBP52 are two cochaperones of progesterone receptors that participate in the progesterone signaling pathway and endometrial receptivity. These 51 and 52 KD proteins increase and decrease the affinity of progesterone hormone receptors to their ligand, respectively. The endometrial tissue of RIF patients might have different patterns of FKBP51 and FKBP52 gene expression. These molecules can easily be detected and quantified by quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) and immunohistochemical (IHC) studies. Assessment ofthese molecules could be a valuable method for evaluationof endometrial receptivity and prediction of the implantation and pregnancy outcome before beginning a treatment cycle for RIF patients in ART procedures.