Fig. 4From: Identification of four key prognostic genes and three potential drugs in human papillomavirus negative head and neck squamous cell carcinomaBoxplots showing mRNA expression of hub genes in normal tissues, HNSCCs, HPV-positive and HPV-negative HNSCCs based on TCGA datasets. The Mann–Whitney U test was performed, and a two-tailed exact P-value of < 0.05 was considered statistically significantBack to article page