Evaluation of p16/Ki-67 Dual Staining Compared with HPV Genotyping in Anal Cytology with Diagnosis of ASC-US for Detection of High-Grade Anal Intraepithelial Lesions

Introduction: Human Papillomavirus (HPV) infection is the main risk factor for anogenital cancer. The objective of this study was to compare p16/Ki-67 dual staining to HPV genotyping in anal cytology samples with an atypical squamous cell of undetermined significance (ASC-US) for the identification of high-grade squamous intraepithelial lesion (HSIL).

Methods: Anal cytology samples with an ASC-US result (n = 111) were collected from patients of a university hospital (Lyon, France) from 2014 to 2015. Cases with remaining squamous cells (n = 82) were stained using p16/Ki-67 dual staining (CINtec-Plus kit) and analyzed for HPV screening (CLART2-PCR kit) using a composite endpoint of biopsy and cytology results on follow-up specimens.

Results: Detection of HSIL on follow-up specimens (5/22 biopsies; 1/29 cytology samples) was obtained in two out of six cases with p16/Ki-17 versus. five out of six with HPV genotyping alone. Sensitivity and specificity to detect HSIL for p16/Ki-67 was 33% (95% confidence interval [CI] [4; 77]) and 49% (95%CI [34; 64]) versus. 83% (95%CI [36; 99.6]) and 13% (95%CI [5; 27]) for HPV genotyping.

Conclusion: Herein, HPV genotyping was more sensitive but less specific than p16/Ki-67 staining for the detection of subsequent HSIL in ASC-US anal cytology. A larger study is required to evaluate the combination of these biomarkers for triage.