Then KEGG analysis showed that the signaling pathways of PNS and aging mainly involved pathways in cancer, proteoglycans in cancer, eGFR tyrosine kinase inhibitor resistance, neurotrophin signaling pathway, apoptosis, chemical carcinogenesis‐receptor activation, PI3K‐Akt signaling pathway, Ras signaling pathway, Rapl signaling pathway, and Alzheimer disease. Here, BDNF is linked to Alzheimer disease.