According to experiments conducted by Wong et al. in 2012 [8], they observed that, in 40 hr-HPV samples with various grades of CIN, in the cervical area, T-cells, DCs, INF-γ, IL-12, and IL-10 express high levels of PD-1 and PD-L1. This evidence concerns the gene CD274 and cervical squamous intraepithelial neoplasia.