PDGFA and head and neck squamous cell carcinoma: The IHC staining (Fig. 10), western blotting and RT-qPCR (Fig. 11) results found that except SERPIAN5, which was relatively low-expressed in HNSCC tissues, the other five genes (OLR1, PDGFA, S100A4, MSX1, and APOH) were all highly expressed in HNSCC tissues.