TNF and obesity due to melanocortin 4 receptor deficiency: The search results in CTD database implied that the all pathways were correlated with Obesity, and the 8 of 20 pathways were related to PCOS, including prion diseases, chagas disease (American trypanosomiasis), staphylococcus aureus infection, AGE-RAGE signaling pathway in diabetic complications, TNF signaling pathway, measles, hepatitis C, and cytokine–cytokine receptor interaction.