INS and polycystic ovary syndrome: It is thought that a possible genetic cause of insulin resistance (IR) in PCOS could be, among others, a high expression of Src homology 2 (SH2) domain-containing adaptor protein (Lnk) in the ovarian cell lines of PCOS women, which inhibits phosphatidylinositol 3 kinase (PI3K) and mitogen-activated protein kinase (MAPK) signaling in response to insulin [5].