In premalignant CIN lesions, alterations of SLIT2 and/or ROBO1 and SLIT2 and/or ROBO2 ligand-receptor pairs were observed in 44% and 39% cases respectively, which increased significantly in the subsequent stage I/II tumors and remained comparable thereafter. This evidence concerns the gene SLIT2 and cervical squamous intraepithelial neoplasia.