Light micrographs of sections through normal, healthy tissue from the cervix wall (left), and tissue with grade 1 (center) and grade 2 cervical intraepithelial neoplasia (right). Cervical Intraepithelial Neoplasia (CIN), also known as cervical dysplasia and cervical interstitial neoplasia, is the potentially premalignant transformation and abnormal growth (dysplasia) of squamous cells on the surface of the cervix. CIN is not cancer, and is usually curable. Most cases of CIN remain stable, or are eliminated by the host's immune system without intervention. However a small percentage of cases progress to become cervical cancer, usually cervical squamous cell carcinoma (SCC), if left untreated. The major cause of CIN is chronic infection of the cervix with the sexually transmitted human papillomavirus (HPV).