FAS and squamous cell intraepithelial neoplasia: Also, median Fas and FasL expression levels were lower in L-SIL (0.18 RUE and 0.25 RUE, respectively, P=0.00001) and H-SIL patients (0.31 RUE and 0.23 RUE, respectively, P=0.009) than in NCL subjects.