CIN is classified into three grades based on the extent of abnormal cell growth: - CIN 1: Mild dysplasia, involving about one-third of the thickness of the cervical lining. - CIN 2: Moderate dysplasia, involving about two-thirds of the thickness of the cervical lining. - CIN 3: Severe dysplasia to carcinoma in situ, involving more than two-thirds of the cervical lining.
