HOXA10 expression is decreased during the secretory phase in subfertile women who have endometriosis, hydrosalpinx, leiomyoma and PCOS.7 Although no changes in HOXA10 protein expression were found in the endometria of women with RIF, sumoylated HOXA10 expression was aberrantly higher in these patients compared with that of fertile control women, suggesting that HOXA10 sumoylation may contribute to impaired endometrial receptivity and embryo implantation failure. This evidence concerns the gene HOXA10 and polycystic ovary syndrome.