SELL and polycystic ovary syndrome: The future assessment of gene expression (and DNA methylation) of endometrial receptivity markers such as CDH6 (cadherin 6), L-selectin ligands, osteopontin and its receptor αvβ3 integrin, and LIF is necessary to provide more information about the association among PCOS pathogenesis, endometrium receptivity, and the metformin and carbohydrate-controlled diet used in the present study [52,53,54,55].