Expression of the P16 and Ki67 in Cervical Squamous Intraepithelial Lesions and Cancer

Purpose: To evaluate the expression of p16 and Ki67 in cervical intraepithelial neoplasia (CIN) and cancer.

Materials And Methods: We performed a immunohistochemical study of p16 and Ki67 in 243 cervical tissues 53 nondysplastic lesions, 106 CIN1, 61 CIN2/3 and 23 squamous cell carcinomas. The expression of p16 and Ki67 was interpreted independently by 2 researchers and the sensitivity and specificity to detect clinically significant lesions (≥ CIN2) were determined.

Results: The overall agreement results of positive or negative immunostaining of intrainter observer variability were 0.659 for p16 and 0.808 for Ki67. p16 expression was demonstrated in 91.3% of invasive carcinomas, 78.7% of CIN2/3, 10.4% of CIN1 and 9.4% of nondysplasic lesions. The corresponding Ki67 expression was: 100% of all invasive carcinomas, 75.4% of CIN2/3, 22.6% of CIN1, and 11.3% with nondysplasia. The expression was significantly different between CIN2/3 vs CIN1 for both p16 and Ki67 (pvalues <0.001 both), and cancer vs CIN2/3 for Ki67 (pvalue 0.008). The differences were not significant between CIN1 vs nondysplasia (pvalues 1.000 for p16 and 0.130 of Ki67), and cancer vs CIN2/3 for p16 (p value 0.219). The sensitivity and specificity to detect > CIN2 were 84.5% and 90.5% by p16 and 82.1% and 88.6% by Ki67.

Conclusions: The rates for 16 and Ki67 expression were directly associated with the severity of cervical lesions. Significant differences in these markers expression may be useful in cases with equivocal histologic features among cervical intraepithelial lesions, but not between CIN1 and nondysplastic lesions. The two markers had high sensitivity and specificity in determining >CIN2.