Light micrograph of a cervical smear revealing moderate dysplasia (CIN 2), the presence of abnormal, blue-staining cells with large, dark nuclei. The CIN grading refers to a spectrum of potentially cancerous changes (dysplasia) in the stratified squamous epithelium that lines the cervix. CIN 1 corresponds to mild dysplasia, CIN 2 to moderate dysplasia & CIN 3 to severe dysplasia & carcinoma-in-situ. In a normal squamous epithelium, cell division is confined to the basal layer; cells mature & rise towards the surface. Normal superficial cells are pink staining, with small nuclei. Dysplastic cells represent a disruption in the maturation process.