MTOR and hydrops fetalis: Arrows and lines indicate a regular relationship between two elements mTOR: mammalian target of rapamycin; PPAR-γ: peroxisome proliferator-activated receptor γ; DHEA: dehydroepiandrosterone; HF: hair follicle; IFN: interferon; TGF-β: transforming growth factor-β; IP: immune privilege; EMT: epithelial-mesenchymal transition; SP: substance P; NK-1: Neurokinin-1.