Further analysis of single CpG site specific methylation within TAP1, LMP7, and ERp57 indicated a significant increase in methylation level of most of the CpG sites at target CpG islands of TAP1, LMP7, and ERp57 genes in CSCC compared to controls, whereas no statistical significance was found between CIN and the control (P>0.05). Here, PSMB8 is linked to cervical squamous intraepithelial neoplasia.