Differentiating Small Cell Carcinoma From Squamous Cell Carcinoma in Cytologic Specimens: A Head-to-Head Comparison of p40 and p63 Using Cell Block Immunocytochemistry

Michael P Gailey; Andrew M Bellizzi; Chris S Jensen

doi:10.1097/PAI.0000000000000177

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Differentiating Small Cell Carcinoma From Squamous Cell Carcinoma in Cytologic Specimens: A Head-to-Head Comparison of p40 and p63 Using Cell Block Immunocytochemistry

Journal article

Peer reviewed

Differentiating Small Cell Carcinoma From Squamous Cell Carcinoma in Cytologic Specimens: A Head-to-Head Comparison of p40 and p63 Using Cell Block Immunocytochemistry

Michael P Gailey, Andrew M Bellizzi and Chris S Jensen

Applied immunohistochemistry & molecular morphology, Vol.24(1), pp.11-15

01/2016

DOI: 10.1097/PAI.0000000000000177

PMID: 25906121

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Abstract

Distinguishing small cell carcinoma (SCC) from poorly differentiated squamous cell carcinoma (SCCA) can be challenging on fine needle aspiration (FNA). p63 immunocytochemistry is frequently used to support the presence of squamous differentiation. However, issues relating to specificity have arisen, and the common pan-p63 clone (4A4) has been challenged by antibodies specific for the ΔN isoform of p63 (p40), which show superior specificity for SCCA. A total of 50 SCC and 25 SCCA FNA cell blocks were stained with antibodies for p40, p63, K903, and CK5/6. For each marker, both extent and intensity of immunoreactivity were recorded, blinded to diagnosis, and H-scores (extent×intensity) were calculated. A total of 4%, 34%, 4%, and 2% of SCCs were positive for p40, p63, K903, and CK5/6, respectively. The rate of p63 positivity was significantly higher than for the other markers. Median H-scores in p63-positive SCCs (40) and SCCAs (270) were significantly different (P<0.0001), though, and 94% of p63-positive SCCs showed an H-score <150. SCCs frequently express p63 (34%). In the SCCA versus SCC differential diagnosis, p40 and K903 are each marginally more sensitive (92%) than p63 (88%), whereas CK5/6 boasts the greatest specificity (98%). p63's poor specificity (66%) can be improved to 94%, if an H-score ≥150 is used as the cutoff for a positive result.

Immunohistochemistry

Lung Neoplasms - genetics

Diagnosis, Differential

Gene Expression

Keratin-6 - genetics

Membrane Proteins - genetics

Antibodies - chemistry

Carcinoma, Squamous Cell - genetics

Carcinoma, Squamous Cell - pathology

Humans

Lung Neoplasms - pathology

Keratin-5 - genetics

Small Cell Lung Carcinoma - genetics

Carcinoma, Squamous Cell - diagnosis

Biopsy, Fine-Needle

Small Cell Lung Carcinoma - pathology

Sensitivity and Specificity

Small Cell Lung Carcinoma - diagnosis

Biomarkers, Tumor - genetics

Cyclin-Dependent Kinases - genetics

Lung Neoplasms - diagnosis

Details

Title: Subtitle: Differentiating Small Cell Carcinoma From Squamous Cell Carcinoma in Cytologic Specimens: A Head-to-Head Comparison of p40 and p63 Using Cell Block Immunocytochemistry
Creators: Michael P Gailey - Department of Pathology, University of Iowa, Iowa City, IA
Andrew M Bellizzi
Chris S Jensen
Resource Type: Journal article
Publication Details: Applied immunohistochemistry & molecular morphology, Vol.24(1), pp.11-15
Publisher: United States
DOI: 10.1097/PAI.0000000000000177
PMID: 25906121
ISSN: 1541-2016
eISSN: 1533-4058
Grant note: P30 CA086862 / NCI NIH HHS
Language: English
Date published: 01/2016
Academic Unit: Pathology
Record Identifier: 9984046911802771

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