Expression of p16INK4a and cervical infection with high-risk human papillomavirus are not related to p53 activity in cervical intraepithelial neoplasia

The role of P16ink4a and P53 immunostaining in predicting recurrence of HG-CIN after conization treatment

Objective: Io evaluate the expression of p16INK4a and p53 biomarkers in conization specimens from patients with high grade cervical intraepithelial neoplasia (HG-CIN), correlating them with the ability to predict the recurrence. Methods : we conducted a retrospective study of patients with HG-CIN in cervical biopsy treated with conization between January 1999 and January 2006 who had a minimum follow-up of 18 months. The expression of the p16 and p53 was assessed by tissue microarrays and correlated with disease recurrence. For analysis, we used the test of proportions (chi-square), considering value p<0.05, 95% CI and calculations of sensitivity, specificity and accuracy of these immunomarkers in predicting recurrence. Results : the series comprised 83 patients aged between 16 and 86 years (35±11.7), divided into two groups: 30 with HG-CIN recurrence (study group) and 53 without recurrence (control group). Mean age, parity, smoking and conization technique were similar in both groups. The p53 expression was present in 43% of the study group and 57% of the control group, and the p16 was present in 43% of the study group and in 57% of the control group (p>0.05). p53 had a positive predictive value (PPV) of 42% and negative predictive value (NPV) of 73%, sensitivity 70%, specificity of 47% and accuracy of 59%. The p16, PPV 42%, NPV 72%, sensitivity 66%, specificity of 49% and accuracy of 56%. Conclusion : immunohistochemistry expression of p53 and p16 showed low sensitivity and low specificity as predictors of HG-CIN recurrence after conization treatment.

Detection and pathological value of papillomavirus DNA and p16INK4A and p53 protein expression in cervical intraepithelial neoplasia

The aim of the present study was to investigate human papillomavirus (HPV) infection and p16^INK4A and p53 protein expression, to evaluate their roles in the pathological diagnosis and grading for cervical intraepithelial neoplasia (CIN). The detection of HPV DNA and p16^INK4A and p53 protein expression were examined in a panel of clinical tissue samples using polymerase chain reaction or immunohistochemistry. In 104 cases, HPV16/18 DNA was identified in 49.0% and HPV6/11 DNA in 9.6% of cases. While in 203 cases, 74.4% positively expressed p16^INK4A and 47.3% positively expressed p53. The expression of p16^INK4A exhibited a significantly higher rate in the CIN I group than in the squamous metaplasia coupled with hyperplasia group (SMH; P<0.0001) and the CIN II–III group (P=0.005). A marked correlation was revealed between the band-like staining pattern of p16^INK4A and HPV16/18 infection. On the contrary, p53 expression was not found to significantly correlate with CIN grade or the HPV16/18 infection status. These results suggested that p16^INK4A expression correlates with a higher grade of CIN and may be used as a diagnostic marker to distinguish between CIN I and SMH, as well as between CIN I and CIN II–III.