MAPK8 and polycystic ovary syndrome: Oxidative stress or excessive reactive oxygen species (ROS) play a crucial role in the pathogenesis of PCOS via various mechanisms including activation of protein kinases (such as JNK as mentioned earlier) and in turn participation in the regulation of various genes, increasing the release of Ca2+ from the endoplasmic reticulum and consequently contributing in the follicular arrest, induction of insulin resistance, and protein, lipid, and DNA oxidation (54-56).