Immunohistochemical detection of p16INK4a in liquid-based cytology specimens on cell block sections.

Publication/Presentation Date

4-25-2007

Abstract

BACKGROUND: Colposcopy biopsy procedure is a standard recommendation for atypical squamous cell cannot exclude high-grade lesion (ASC-H) in abnormal Papanicolaou smears. p16 (p16INK4a), a cell cycle regulator, has been shown to be overexpressed in squamous dysplasia. To further improve the diagnostic accuracy of the ASC-H Papanicolaou smear and to reduce unnecessary procedures, the authors evaluated the utility of immunodetection of p16 in liquid-based cytology specimens on cell blocks.

METHODS: Seventy-five liquid-based (SurePath; TriPath Imaging, Inc. Burlington, NC) cytology specimens were prepared for cell blocks. Three groups (G1, G2, and G3) of cases were included: G1 comprised 44 cases of ASC-H; G2, 14 cases of high-grade dysplasia; and G3, 17 negative/reactive cases. All cases in G1 were confirmed by cervical biopsy or Digene Hybrid Capture 2 (Digene, Gaithersburg, Md) human papilloma virus (HPV) testing. Immunodetection for p16 was performed on cell blocks.

RESULTS: In G1, 26 of 44 (59%) cases showed squamous dysplasia, with 14 high-grade squamous intraepithelial lesion (HSIL) cases. Twenty-two of 28 (79%) p16-positive cases were confirmed by surgical biopsy or HPV testing, with a diagnostic sensitivity of 85%, specificity of 67%, positive predictive value (PPV) of 79%, and negative predictive value (NPV) of 75%. Four cases with false-negative staining for p16 were identified. All 28 cases of HSIL (14 from G1 and 14 from G2) were positive for p16.

CONCLUSIONS: 1) p16 is a sensitive marker to confirm the diagnosis of ASC-H on a cell block; 2) Multiple unstained slides with adequate cellularity can be obtained from each cell block; and 3) Additional markers can be used to further increase diagnostic sensitivity and specificity.

Volume

111

Issue

2

First Page

74

Last Page

82

ISSN

0008-543X

Disciplines

Medicine and Health Sciences

PubMedID

17330305

Department(s)

Department of Pathology and Laboratory Medicine

Document Type

Article

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