A broad-based approach to differentiate CIN from its mimics: The utility of in situ hybridization and immunohistochemistry

Hierarchical evaluation of histology and p16-labeling can improve the risk assessment on cervical intraepithelial neoplasia progression

OBJECTIVE

High-grade cervical lesions (HSIL) are associated with the presence of high-risk HPV types, tissue expression of p16, and increased chance of malignant progression, requiring surgical intervention. To improve risk evaluation, we assessed the discriminatory power of the histological findings associated with p16 immunohistochemistry (IHC) staining to classify the low-grade cervical lesion (LSIL) and HSIL.

METHODS

We collected cervical biopsies from colposcopy-visible lesions and non-affected tissue (adjacent to the lesions) of 62 Brazilian women and labeled them with anti-p16 antibodies. In addition to the observational pattern and labeling to define the latent classes (affected vs. non-affected), a computational tool was used for semi-quantitative analysis of p16 expression. The intensity of staining of the nucleus or cytoplasm was captured using the Gimp 2.10 software. ROC curves were used to determine cutoff values for p16 expression in patients classified as LSIL and HSIL by latent class statistics for each labeling stratum.

RESULTS

p16 nuclear labeling showed the best sensitivity and specificity to discriminate LSIL with low p16 expression (62%) and HSIL with high p16 expression (37%). Many patients whose lesions had intermediate levels of p16 nuclear staining were subsequently stratified according to the expression of p16 in the cytoplasm, indicating that five of 21 LSIL were at risk of progression, and 13 of 41 HSIL at risk of regression.

CONCLUSIONS

We suggest a hierarchical analysis, with histology at the first level, followed by a labeling analysis in the nucleus and then in the cytoplasm to increase the accuracy of the HPV cervical lesion stratification.