PCNA and skin cancer: The anticancer potential of scopoletin isolated from Gelsemium sempervirens was shown in 7,12-dimethylbenz(α)anthracene- (DMBA-) induced skin cancer in mice and was mediated by decreasing aryl hydrocarbon receptor (AhR), cytochrome P450 (CYP) 1A1, proliferating cell nuclear antigen (PCNA), signal transducer and activator of transcription-3 (Stat-3), survivin, matrix metalloproteinase-2 (MMP-2), cyclin D1, and c-myc mediators of carcinogenesis [65].