The Ki67+ proliferation index correlates with increased cellular retinol-binding protein-1 and the coordinated loss of plakophilin-1 and desmoplakin during progression of cervical squamous lesions

Aims: To investigate the modulation of cellular retinol‐binding protein (CRBP)‐1 and the desmosomal plaque proteins plakophilin (PKP)‐1 and desmoplakin (DP) in correlation with the Ki67+ proliferation index (PI) during the progression of cervical squamous intraepithelial lesions (SIL) to squamous cell carcinoma (SCC). Methods: Using in situ imaging by brightfield and confocal laser scanning microscopy, the expression of CRBP‐1 protein and transcripts, PKP‐1, DP and the Ki67 PI were analysed in 38 low‐grade (L) SIL, 56 high‐grade (H) SIL, 49 SCC, 30 control cervices and 10 human papillomavirus‐positive condylomatous lesions. Results: CRBP‐1+ cells increased from 11.4% in the normal cervix to 80.3% in LSILs, 92.3% in HSILs and slightly decreased to 78.3% in invasive SCCs (P = 0.0001) in close association with the Ki67 PI (r =0.41; P