Evaluation of CINtec PLUS® testing as an adjunctive test in ASC‐US diagnosed SurePath® preparations

Abstract

The CINtec PLUS® system is an immunohistochemical cocktail composed of antibodies against p16(INK4a) (surrogate of HPV infection) and Ki-67 (proliferation marker) meant to improve the sensitivity and specificity for detecting high-grade dysplasia (HGD). In the presence of dysplasia, a red chromogen marks Ki-67 expression in the nucleus and a brown chromogen marks cytoplasmic p16(INK4a) expression. Only cells showing dual staining are interpreted as positive. This retrospective study examined the performance of CINtec PLUS testing when performed on ASC-US diagnosed samples. Comparison was made to high-risk HPV DNA test results and colposcopic biopsy results. Technical considerations in the interpretation of this immunohistochemical stain are additionally discussed. CINtec PLUS showed modest sensitivity (64%) and specificity (53%) in identifying the presence of HGD at surgical biopsy. Positive and negative predictive values for HGD were 28% and 83%, respectively. HR-HPV DNA test yielded sensitivity of 100% and specificity of 21%. During interpretation, squamous metaplasia and endocervical cells were seen to show individual staining for p16(INK4a) or Ki-67. Individual staining, when present within three dimensional cellular groups common to SurePath® preparations, can be time-intensive to interpret necessitating thoughtful examination at high power. The Pap test with HR-HPV DNA testing is a highly sensitive test. A specific test is needed to prevent false positives and over treatment. The CINtec® system provides a modest increase in specificity beyond HR-HPV DNA testing. Future study of its appropriateness and cost-ffectiveness in a treatment algorithm are warranted.

p16INK4a immunocytochemistry versus human papillomavirus testing for triage of women with minor cytologic abnormalities

“…In two studies 12;26 p16 INK4a /Ki-67 dual staining using CINtec Plus kit was performed, the other 15 studies 23–25;27–38 applied single p16 INK4a imumnocytochemistry. Twelve studies 23–25;28–33;36–38 used clone E6H4 as a primary antibody for p16 INK4a , other primary antibodies used were Clone 6H12 27 , Clone JC8 34 and 16P04 35 .…”

Predictive Value of the Combined p16^INK4a and Ki-67 Immunocytochemistry in Low-Grade Squamous Intraepithelial Lesions

“…The combined immunocytochemical detection of p16 INK4a and Ki-67 (CINtec® PLUS) shows higher positive predictive values (PPV) for cervical intraepithelial neoplasia (CIN) grade 2 or higher (CIN2+) than cytology or high-risk HPV test results in international studies [1,2,3]. Most studies examined the value of the p16/Ki-67 dual stain for the triage of atypical squamous cells of undetermined significance (ASC-US)/LSIL findings based on colposcopy and biopsy results [4,5,6,7,8,9,10], but only limited follow-up data were provided. Such studies are prone to be methodologically inaccurate [11,12] since prognostically relevant conclusions can only be drawn from prospective studies with follow-up investigations that are relevant for the individual patient management.…”

Dual p16 and Ki-67 Expression in Liquid-Based Cervical Cytological Samples Compared to Pap Cytology Findings, Biopsies, and HPV Testing in Cervical Cancer Screening: A Diagnostic Accuracy Study

“…undetermined significance (ASC-US), that are considered "possibly nonneoplastic," can later show in the histopathological examination as low-grade squamous intraepithelial lesions (LSIL) in 5-22% of the cases [8][9][10]. In fact, 9-30% of patients with screening examination indicating LSIL may even have high-grade lesions (HSIL or ASC-H) in a significant number of cases [11,12].…”