Fig. 1

Differential expression of PD-L1 in cervical tissues by immunohistochemistry (× 200). a, Weak expression of PD-L1 in a woman without CIN (light brown staining, score 1). b, PD-L1 expression in a woman with CIN III revealing strong membranous staining in cervical epithelial cells and infiltrating mononuclear cells (dark brown, score 3). e, epithelium; s, stroma