Investigating the correlation between immunohistochemical markers and the recurrence of OSCC and oral epithelial dysplasia (OED) following PDT, Uehara M. et al. found that vascular endothelial growth factor (VEGF) expression was significantly lower in the recurrence group, suggesting its potential as a predictive marker for PDT effectiveness [165]. This evidence concerns the gene VEGFA and dysplastic oral keratinocyte.