Likewise, we looked into HPV-positive HNSCC tumours with different grades in the TCGA and found that higher grade tumours appeared to have higher expression of BRD4, CDKNA2, RAD51AP1 and CDC6 with EGFR expression was lesser in higher tumour grades (Fig. S4B) [44]. This evidence concerns the gene CDC6 and head and neck squamous cell carcinoma.