1 In CIN1, not much of the tissue looks abnormal, and it is considered the least serious cervical pre-cancer (mild dysplasia). 2  In CIN2 more of the tissue looks abnormal (moderate dysplasia). 3  In CIN3 most of the tissue looks abnormal; CIN3 is the most serious pre-cancer (severe dysplasia) and includes carcinoma in situ).IN is graded on a scale of 1 to 3 based on how much of the cervical tissue looks abnormal when viewed under the microscope. 1  In CIN1, not much of the tissue looks abnormal, and it is considered the least serious cervical pre-cancer (mild dysplasia).