Immunohistochemical Expression of Cyclin D1, p16Ink4a, p21WAF1, and Ki-67 Correlates With the Severity of Cervical Neoplasia

High-risk human papillomaviruses are closely associated with cervical cancer and its precursor lesions through interactions between the E6 and E7 oncoproteins and the cell-cycle regulatory proteins, such as p53 and pRb, respectively. As other molecules involved in the cell-cycle control seem to be important for human papillomavirus (HPV)-mediated cervical carcinogenesis, we have analyzed the expression of p53, p21, p16, cyclin D1, and Ki-67 and the presence of HPV (HPV pool and HPV-16) by immunohistochemical studies using tissue microarray in low squamous intraepithelial lesions (n=50), high squamous intraepithelial lesions (n=98), and cervical carcinoma (n=18). We have found a significant increase in the expression of p16 and p21 (P<0.001) from low- to high-grade lesions and cancer. In contrast, cyclin D1 expression showed a significant decrease in more severe lesions (P<0.001). p16, Ki-67, p21, and p53 positivity increased with the cell-layer level and the lesion severity, with stronger correlations being observed for p16 and Ki-67. High positivity for HPV pool (96.3%) and HPV-16 (77.5%) immunostaining was detected in all cases, with an association between p16 and cyclin D1 expression and HPV-16 infection. Our tissue microarray results corroborate the usefulness of the immunohistochemical assessment of cell-cycle biomarkers in distinguishing different groups of precursor lesions of the cervix and cervical carcinoma.