Fig. 2From: Overexpression of programmed cell death ligand 1 in patients with CIN and its correlation with human papillomavirus infection and CIN persistenceDifferential expression of Ki-67 in cervical tissues by immunohistochemistry (× 200). a, Weak expression of Ki-67 in a woman with CIN I. b, Ki-67 expression in a woman with CIN III revealing strong nuclear staining in cervical epithelial cells. e, epithelium; s, stromaBack to article page