title: The application and diagnostic utility of immunocytochemistry on direct smears in the diagnosis of pulmonary adenocarcinoma and squamous cell carcinoma.
abstract: The importance of subclassifying pulmonary nonsmall cell carcinoma (NSCLC) in cytologic material is becoming increasingly paramount. Occasionally, cell blocks traditionally used for ancillary studies are sparsely cellular or acellular. Hence, we investigated the diagnostic utility of immunocytochemistry for Napsin-A, TTF-1, and p63 on direct smears of NSCLC. Immunohistochemistry for Napsin-A was initially tested on a tissue microarray (TMA) composed of pulmonary adenocarcinoma. Subsequently, in 25 cases, immunocytochemistry for Napsin-A, TTF-1, and p63 was performed on cytologic direct smears. Smears were prepared from tumor cells scraped from lung resection specimens (n = 10), endobronchial ultrasound-guided transbronchial fine-needle aspirates (n = 13), and pelleted cell material from pleural effusions (n = 2). Immunohistochemistry utilizing the TMA revealed Napsin-A positivity in 73% of pulmonary ADCs. Next, immunocytochemistry on direct cytologic smears demonstrated a Napsin-A(+)/TTF-1(+) immunophenotype in 15 of 18 adenocarcinomas; p63 was completely negative (n = 12) or only focally positive (n = 3) in these 15 adenocarcinomas. The remaining three adenocarcinomas were negative for all three markers. All six squamous cell carcinomas were Napsin-A(-)/TTF-1(-) and diffusely p63(+). In conclusion, direct smears represent a feasible and robust source of cellular material for immunocytochemical studies to diagnose pulmonary ADC and SQC. Our method allows the cytologist to confirm on site that material for diagnostic immunocytochemistry is present thereby serving as a safeguard in instances where the cell block is of insufficient cellularity.
authors.affiliation: Department of Pathology, University of Michigan Medical School, Ann Arbor, Michigan 48109, USA.
authors.forename: Michael H
authors.initials: MH
authors.lastname: Roh
authors.forename: Lindsay
authors.initials: L
authors.lastname: Schmidt
authors.forename: Jeremiah
authors.initials: J
authors.lastname: Placido
authors.forename: Sara
authors.initials: S
authors.lastname: Farmen
authors.forename: Kristina L
authors.initials: KL
authors.lastname: Fields
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Courey
authors.forename: Douglas A
authors.initials: DA
authors.lastname: Arenberg
authors.forename: Stewart M
authors.initials: SM
authors.lastname: Knoepp
mesh_terms: D000230:Adenocarcinoma / Q000175:diagnosis*; D000077192:Adenocarcinoma of Lung; D016282:Aspartic Acid Endopeptidases / Q000032:analysis; D014408:Biomarkers, Tumor / Q000032:analysis; D002294:Carcinoma, Squamous Cell / Q000175:diagnosis*; D004268:DNA-Binding Proteins / Q000032:analysis; D061765:Endoscopic Ultrasound-Guided Fine Needle Aspiration / Q000379:methods; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods*; D016130:Immunophenotyping / Q000379:methods; D008168:Lung / Q000473:pathology; D008175:Lung Neoplasms / Q000175:diagnosis*; D008565:Membrane Proteins / Q000032:analysis; D010996:Pleural Effusion / Q000473:pathology; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D046888:Tissue Array Analysis; D014157:Transcription Factors
chemical_list: D014408:Biomarkers, Tumor; C081876:CKAP4 protein, human; D004268:DNA-Binding Proteins; D008565:Membrane Proteins; C504003:TTF1 protein, human; D014157:Transcription Factors; D016282:Aspartic Acid Endopeptidases; C498549:NAPSA protein, human