Fig. 5

The therapeutic effect of vemurafenib on the PCP mouse model. A: Imaging changes caused by vemurafenib therapy in the PCP mouse model. Vemurafenib therapy on the BRAFv600e⁺ PCP mice: at the 1th day of the therapy, mouse MRI showed cystic cavity and solid component of the tumor( yellow arrow). At the 7th day of the therapy, the cystic cavity and solid component of the tumor had significantly shrunk (yellow arrow) (n = 7). The tumors in the brains of the control mice (without any treatment) continued to grow, with the red arrow indicating solid tumor components (n = 3). Vemurafenib therapy on the BRAFv600e⁻PCP mice: at the 1th day of therapy, mouse MRI showed solid component of the tumor (blue arrow). At the 7th day of therapy, the solid component of the tumor continued to grow (blue arrow) (n = 6). The tumors in the brains of the control mice (without any treatment) also continued to grow (green arrow) (n = 3). B: The average volume of BRAFv600e⁺ PCPs significantly decreased on the 7th day of therapy. (P < 0.001); however, the average volume of BRAFv600e⁻ PCPs continued to increase on the 7th day of therapy (P > 0.05). C: Histological changes caused by vemurafenib therapy in the PCP mouse model. Vemurafenib therapy on the BRAFv600e⁺ PCP mice (n = 7): at the 7th day of the therapy, the squamous epithelium completely disappeared, leaving scar tissue. Vemurafenib therapy on the BRAFv600e⁻ PCP mice (n = 6): at the 7th day of therapy, the squamous epithelium was still intact in the tumor tissue, which was similar to that of the control mice. D: Pathological changes caused by vemurafenib therapy in the PCP mouse model. In BRAFv600e⁺ PCP mice (n = 7), beta-catenin and Pan-CK expression was negative in the tumor tissue. However, in BRAFv600e⁻ PCP mice (n = 6), beta-catenin and Pan-CK expression was still positive in the tumor tissue after vemurafenib therapy, which was very similar to the findings in the control mice (n = 3)