To ascertain this, herein we studied mRNA, soluble proteins, and cell surface protein expression of Fas and FasL in peripheral blood mononuclear cells (PBMCs) from low- and high-grade squamous intraepithelial lesion (L-SIL and H-SIL, respectively) and CC patients, and compared them with cells from women with no cervical lesions. Here, FAS is linked to squamous cell intraepithelial neoplasia.