p16 Immuno-cytochemistry shows superior clinical performance to HPV testing

06-23-2010: mtm laboratories announced the publication of a large study in the American Journal of Clinical Pathology that evaluated the clinical performance of the CE-labeled CINtec® Cytology kit in managing equivocal or mildly abnormal cytologic results.

The publication authored by Denton and colleagues and titled ”The Sensitivity and Specificity of p16INK4a Cytology vs. HPV Testing for Detecting High-Grade Cervical Disease in the Triage of ASC-US and LSIL Pap Cytology Results” shows that the interpretation of p16 cytology slides has the potential to provide a high sensitivity, with significantly higher specificity for the identification of high-grade CIN than High-risk Human Papillomavirus (HR-HPV) testing for the management of women with Pap cytology results categorized as ASC-US (Atypical Squamous Cells of Undetermined Significance) or LSIL (Low-grade Squamous Intraepithelial Lesion). These two Pap cytology categories are particularly difficult to interpret but cannot be dismissed as the majority of cases are benign, however, up to 15 % of women with such a cytology result harbor high-grade CIN disease, the immediate pre-cursor to cervical cancer.

The performance of p16INK4a immuno-cytochemistry (p16 Cytology) and HPV testing was analyzed on a series of 810 retrospectively collected ASC-US and LSIL cases. The diagnostic performance of each test was compared using the disease end point of biopsy confirmed high-grade disease (CIN2+). The sensitivity (i.e. ability to find established disease) of the two tests identifying CIN2+ was similar (p16 Cytology, up to 92.6% in ASC-US, and up to 92.2% in LSIL, vs. HPV testing found at 90.1% in ASC-US, and 95.7% in LSIL). However, the specificity of p16 Cytology was up to two times higher than that of HPV testing. This means that significantly less women would need to be sent on for further diagnostic follow-up, while still being able to identify those with established high-grade disease.

Bob Silverman, CEO of mtm laboratories, commented: “It is important to identify women within the screening program who are most likely to harbor high-grade disease with the least amount of intervention. The results of this study published in this peer review journal show that CINtec Cytology may set a new performance standard for the triage of both ASC-US and LSIL Cytology results.”

Original publication: Denton KJ, Bergeron C, Klement P, Trunk MJ, Keller T, Ridder R; "The Sensitivity and Specificity of p16INK4a Cytology vs HPV Testing for Detecting High-Grade Cervical Disease in the Triage of ASC-US and LSIL Pap Cytology Results."; Am J Clin Pathol 2010;134:12-21.