FIG 4 .

Analysis of RB1 mutations shows detrimental effects independent of HPV protein expression. (A) Locations and types of RB1 mutations are annotated on the full-length Rb protein to determine functional effects. Mutations at specific locations are indicated by a letter representing the type of mutation. Underlined letters represent an HPV⁺ sample, and plain letters represent an HPV⁻ sample. Amino acid changes are identified for missense mutations. RBN, Rb amino-terminal domain; RBC, Rb carboxy-terminal domain. (B) RNA levels of HPV E7 in HPV⁺ RB1 mutant (red) and RB1 wild-type (blue) HNSCC tumors were analyzed using a boxplot. Data for outliers are in black. (C) The t test was used to compare the average RNA levels for other HPV proteins (E4, E5, E6, and E7) between the two groups (HPV⁺ RB1 mutant and RB1 wild-type HNSCC tumors), to check for any significant differences between these two groups.