PLPP4 and head and neck squamous cell carcinoma: We screened 20 key genes (PDGFRB, PLPP4, CALU, ADAMTS14, COL5A3, KCNE4, LOXL1, CLEC11A, PODN,BGN, AEBP1, COL1A2, LAMA4, LOXL2, LRRC15, THY1, SPON2, COL1A1, NID2, and AC134312.5) including and as to decide the neighbor genes biological interaction network of these 20 stemness-related genes in HNSCC.