PAX1 and squamous cell carcinoma: Several studies found that PAX1 methylation increased along with increased disease grade in the following order: PAX1 methylation in squamous cell carcinoma (SCC) > high‐grade squamous intraepithelial lesion (HSIL) > low‐grade squamous intraepithelial lesion (LSIL) > normal tissue (Lai et al., 2008; Lim et al., 2010; Xu et al., 2015).