Further, we studied the correlation among VEGFA, STAT3, KLF4 and CDKN1A genes in KIRC, OV and GBM, with the results showing that the correlation among VEGFA, STAT3, KLF4 and CDKN1A genes in KIRC and OV was consistent with that in HNSCC (Figs. 7A–7J). This evidence concerns the gene STAT3 and head and neck squamous cell carcinoma.