CST3 and cervical squamous intraepithelial neoplasia: Furthermore, CIN patients had significantly enhanced Cystatin C levels (CIN vs. non-CIN, 1.4±0.8 vs. 0.9±0.3 mg/dl, P = 0.046) and reduced NO levels (CIN vs. non-CIN, 33±24 vs. 51±29 μmol/l, P = 0.031).