laboratory developed dual p16ink4a/ki-67 immunocytochemical stain in a cervical pap smear screening...

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S46 Abstracts

Table 1 Summary of 103 PAP Cases with Follow-up

Diagnosis Surgical Biopsy Follow-up Cytology Follow-up HSIL

Benign

LSIL(CIN1)

HSIL(CIN2-3)

Benign

HPV + LSIL

BENIGN (nZ60)

2 (3%) 0 (0%) 1 (2%) 57 (95%) 0 (0%) 0 (0%) 0 (0%)

ASC-H (nZ15)

2 (13%) 4 (27%) 6 (40%) 3 (20%) 0 (0%) 0 (0%) 0 (0%) ASCUS (nZ4) 1 (25%) 0 (0%) 0 (0%) 2 (50%) 1 (25%) 0 (0%) 0 (0%) SIL (nZ6) 0 (0%) 0 (0%) 5 (83%) 0 (0%) 0 (0%) 0 (0%) 1 (17%) AGUS (nZ16) 5 (31%) 1 (6%) 4 (25%) 4 (25%) 2 (13%) 0 (0%) 0 (0%) OTHERS (nZ2) 0 (0%) 0 (0%) 2 (100%) 0 (0%) 0 (0%) 0 (0%) 0 (0%)

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Laboratory Developed Dual p16ink4a/Ki-67 ImmunocytochemicalStain in a Cervical Pap Smear Screening Population: A Proof ofConcept Study

Brent Bedke, MD, Michael Callanan, SCT(ASCP), Michael Henry, MD,LouAnn Gross. Mayo Clinic, Rochester, Minnesota

Introduction: CINtec Plus (Roche) p16/Ki67 dual immunocytochemicalstaining in cervical cytology specimens is reported to improve sensitivityand specificity for detecting subsequent high grade dysplasia (�CIN2).CINtec Plus is not generally available in the United States. The aim of thisstudy is to evaluate the performance of a laboratory developed p16/Ki-67dual stain in a cervical cytology screening population.Materials and Methods: Cases were identified retrospectively from internalfiles and were selected by cytologic diagnosis. p16Ink4a (clone EPR1473,Abcam) and Ki-67 (clone Mib1, Dako) antibodies were initially calibratedon histologic sections and then optimized on Thinprep slides using alcoholfixed residual volumes. Cytology cases expressing p16 and Ki-67 withinthe same cell were considered dual stain positive. HPV results, whenperformed, were also included. Histology was considered the gold standardfor dysplasia and cases without histologic follow-up per ASCCP guidelineswere excluded.Results: A total of 40 cases were evaluated. 25 cases were negative for highgrade dysplasia (<CIN1) (Table 1) and 15 cases were positive (�CIN2) onhistology (Table 2). The percentage of dual stain positive cases by cytologiccategory is represented in Figure 1. Sensitivity was 87%, specificity was68%, positive predictive value was 62% and negative predictive value was89% (Figure 2). Eight dual stain false positives occurred in the <CIN1group and were due to reactive endocervical cells (nZ4), follicularcervicitis (nZ1) and indeterminate (nZ3). Two false negatives occurredin the �CIN2 group and were due to sampling error (nZ1) and stainingerror (nZ1).Conclusions: Our laboratory developed p16/Ki67 dual stain has increasedsensitivity and a high negative predictive value. False negative and falsepositive results hinder accurate classification but may be resolved withcareful morphologic correlation. Additional studies to determine accuratestratification of ASCH/ LSIL cytology categories in HPV+ patients arecurrently underway.

Table 1

Biopsy <CIN1

Cytology Dx

HPV Dual

NEG

NEG NEG NEG NEG NEG NEG NEG NEG NEG NEG NEG NEG NEG NEG NEG NEG NEG NEG NEG NEG NEG NEG POS NEG NEG POS NEG NEG POS NEG NEG POS NEG NEG NEG ASCH NEG NEG ASCH NEG NEG ASCH POS NEG

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Table 1 (continued )

Biopsy <CIN1

Cytology Dx

HPV Dual

ASCH

POS NEG ASCH POS NEG ASCH NA POS ASCH POS POS LSIL+ NEG NEG LSIL+ POS NEG LSIL+ NEG POS LSIL+ NA POS HSIL NEG NEG HSIL NEG NEG

Table 2

Biopsy CIN�2

Cytology DX

HPV Dual

NEG

POS POS ASCH NA NEG ASCH NA NEG ASCH NA POS ASCH NA POS ASCH POS POS LSIL+ POS POS LSIL+ POS POS HSIL POS POS HSIL POS POS HSIL POS POS HSIL POS POS HSIL POS POS HSIL POS POS HSIL POS POS

Figure 1

Figure 2

CIN�2 CIN<1

DualStain

Positive

13 8 PPV Z 62% Negative 2 17 NPV Z 89%

Sensitivity Z 87%

Specifity Z 68%

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The Evaluation of Sensitivity and Specificity of the CINtec� Plus Kitfor p16 and Ki-67 in HPV Related Lesions

Desiree Palafox, BS, SCT(ASCP), Desiree Carrillo, BS,Margaret Tavares, BS, SCT(ASCP), Crystal Hernandez, BS, CT(ASCP),Pamela Wat, MD. Loma Linda University, Loma Linda, Califormia

Introduction: Persistent Human Papillomavirus (HPV) infection with high-risk HPV types 16 and 18 is a precursor to cervical carcinoma. The E7oncoprotein associatedwithHPVtype 16and carcinogenesis of cervical lesionscauses deregulated cell cycles. Disabled by the E7 oncoprotein, the cellscontinue to proliferate causing the simultaneous overexpression of p16INK4aandKi-67. TheCINtec� PlusKit (Roche-mtm labs) is an immunocytochemical