[430] Utility of Multiplex TTF-1 & Napsin A and p63 & CK5 Immunostains in Distinguishing Lung Adenocarcinoma from Squamous Cell Carcinoma in FNA Specimens.

Seema Sethi, Vinod B Shidham, Lili Geng, Pamela Archuletta, Sudeshna Bandyophadhyay, Jining Feng, Shashi Madan, Dongping Shi, Paul Tranchida, Tamar Giorgadze. Wayne State University, Detroit, MI

Background: The distinction of lung adenocarcinoma from squamous cell carcinoma has important therapeutic implications. Napsin A is a recently developed marker which has shown high specificity for lung tissue in surgical pathology specimens. In this study we evaluated whether use of novel multiplex TTF-1 & Napsin A and p63 & CK5 immunostains will improve the diagnostic accuracy of primary lung adenocarcinoma versus squamous cell carcinoma in FNA specimens.
Design: A total of 35 consecutive cases of formalin fixed, paraffin embedded adequately cellular FNA cell blocks, with a confirmed diagnosis of either lung primary adenocarcinoma (ACA, n=13) or squamous cell carcinoma (SCC, n=15) or poorly differentiated carcinoma (PDC, n=7) were included in the study. Two immunostain cocktails 'TTF-1 & Napsin A' and 'p63 & CK5' were used for dual immunostaining with cost analysis. All slides were scored in a blinded manner by two pathologists. The presence of one or more individual tumor cells with convincing brown nuclear TTF-1 and red cytoplasmic Napsin A immunostaining, cells with brown nuclear p63 and red cytoplasmic CK5 immunostaining, or cells with co-expression were interpreted as “positive”.
Results: Good quality sections suitable for interpretation of immunostains were obtained from all 35 FNA cell blocks. All 15 FNA cell blocks from SCC cases were positive with the dual stain for p63 & CK5 and negative for the dual stain for TTF-1 & Naspin A. All 13 ACA cases were positive with the dual stain for TTF-1 & Naspin A and negative with the dual stain for p63 & CK5 (Sensitivity 100%; Specificity 100%). Of the 7 PDC cases, 5 cases were positive with the dual stain p63 & CK5 and negative for the dual stain TTF-1 & Naspin A consistent with SCC; 2 cases were positive with the dual stain for TTF-1 & Naspin A and negative for the dual stain p63 & CK5 consistent with ACA.
Conclusions: Primary ACA and SCC of the lung have distinct non-overlapping dual immunostaining patterns with Napsin A & TTF-1 in ACA and p63 & CK5 co-expression in SCC.
Napsin A & TTF-1 and p63 & CK5 dual immunostaining increases sensitivity and specificity of distinguishing primary lung ACA from SCC in FNA specimens.
The panel of multiplex Napsin A & TTF-1 and p63 & CK5 immunostains is potentially useful in differentiating ACA from SCC in lung FNA specimens with poorly diiferentiated carcinoma, especially in FNA specimens with scant cellularity.
The panel of multiplex Napsin A & TTF-1 and p63 & CK5 immunostains is cost-effective.
Category: Cytopathology

Tuesday, March 1, 2011 8:45 AM

Platform Session: Section F, Tuesday Morning

 

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