HIF1A and head and neck squamous cell carcinoma: The results indicated that the expression of CCND1, PDGFRB, HIF1A, PXDN and MMP2 was significantly reduced in the HPV+ HNSCC (Figure 6A, Supplementary Figures S8B-E), and the expression of MAPK1 was no difference in HPV+ HNSCC (Supplementary Figure S8A).