APC and cervical squamous intraepithelial neoplasia: Other studies have associated CIN with inactivating mutations or losses in the adenomatous polyposis coli (APC) tumour suppressor gene, which occur as an early event in the development of bowel neoplasia in this sequence, and/or inactivation of TP53, the guardian of the genome, or other pathway members [2, 9, 10].