Proliferation and p53 expression in anal cancer precursor lesions

Background: Anal squamous cell carcinoma (SCC) develops from dysplastic anal warts. This study quantifies the expression of p53 and Ki67 in pre-invasive and invasive anal lesions. Materials and Methods: Samples of 70 patients with anal warts (n=20), low grade anal intraepithelial neoplasia (LG AIN) (n=12), high grade anal intraepithelial neoplasia (HG AIN) (n=27) and anal SCC (n=11) were stained using immunohistochemical techniques. Eight patients with normal anal skin were used as controls. Results: Both the expression of p53 and Ki67 increased significantly (p<0.001) and gradually as the lesions became dysplastic and invasive. The main increase in p53 expression was as the lesions progressed from anal warts (7.38+/-11.93-mean+/-SD) to low grade AIN (20.778+/-13.14). Conclusion: p53 is involved in the progression of anal cancer and its expression increases from early in the development of pre-invasive anal lesions. p53 and Ki67 may be useful markers of early dysplasia and should be considered in the screening of high risk patients.