title: Refining the diagnosis and EGFR status of non-small cell lung carcinoma in biopsy and cytologic material, using a panel of mucin staining, TTF-1, cytokeratin 5/6, and P63, and EGFR mutation analysis.
abstract: BACKGROUND
  The dichotomization of non-small cell carcinoma (NSCLC) subtype into squamous (SQCC) and adenocarcinoma (ADC) has become important in recent years and is increasingly required with regard to management. The aim of this study was to determine the utility of a panel of commercially available antibodies in refining the diagnosis on small biopsies and also to determine whether cytologic material is suitable for somatic EGFR genotyping in a prospectively analyzed series of patients undergoing investigation for suspected lung cancer.
  
  
  METHODS
  Thirty-two consecutive cases of NSCLC were first tested using a panel comprising cytokeratin 5/6, P63, thyroid transcription factor-1, 34betaE12, and a D-PAS stain for mucin, to determine their value in refining diagnosis of NSCLC. After this test phase, two further pathologists independently reviewed the cases using a refined panel that excluded 34betaE12 because of its low specificity for SQCC, and refinement of diagnosis and concordance were assessed. Ten cases of ADC, including eight derived from cytologic samples, were sent for EGFR mutation analysis.
  
  
  RESULTS
  There was refinement of diagnosis in 65% of cases of NSCLC to either SQCC or ADC in the test phase. This included 10 of 13 cases where cell pellets had been prepared from transbronchial needle aspirates. Validation by two further pathologists with varying expertise in lung pathology confirmed increased refinement and concordance of diagnosis. All samples were adequate for analysis, and they all showed a wild-type EGFR genotype.
  
  
  CONCLUSIONS
  A panel comprising cytokeratin 5/6, P63, thyroid transcription factor-1, and a D-PAS stain for mucin increases diagnostic accuracy and agreement between pathologists when faced with refining a diagnosis of NSCLC to SQCC or ADC. These small samples, even cell pellets derived from transbronchial needle aspirates, seem to be adequate for EGFR mutation analysis.
authors.affiliation: Department of Histopathology, Royal Brompton Hospital, London. a.nicholson@rbht.nhs.uk
authors.forename: Andrew G
authors.initials: AG
authors.lastname: Nicholson
authors.forename: David
authors.initials: D
authors.lastname: Gonzalez
authors.forename: Pallav
authors.initials: P
authors.lastname: Shah
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Pynegar
authors.forename: Manjiri
authors.initials: M
authors.lastname: Deshmukh
authors.forename: Alexandra
authors.initials: A
authors.lastname: Rice
authors.forename: Sanjay
authors.initials: S
authors.lastname: Popat
mesh_terms: D000230:Adenocarcinoma / Q000175:diagnosis* / Q000235:genetics / Q000378:metabolism; D014408:Biomarkers, Tumor / Q000235:genetics / Q000378:metabolism*; D044963:Biopsy, Fine-Needle; D002289:Carcinoma, Non-Small-Cell Lung / Q000175:diagnosis* / Q000235:genetics / Q000378:metabolism; D002294:Carcinoma, Squamous Cell / Q000175:diagnosis* / Q000235:genetics / Q000378:metabolism; D003581:Cytodiagnosis / Q000379:methods; D004252:DNA Mutational Analysis; D004273:DNA, Neoplasm / Q000235:genetics; D003937:Diagnosis, Differential; D066246:ErbB Receptors / Q000235:genetics*; D005838:Genotype; D006801:Humans; D007124:Immunoenzyme Techniques; D053555:Keratin-5 / Q000378:metabolism; D053553:Keratin-6 / Q000378:metabolism; D008175:Lung Neoplasms / Q000175:diagnosis* / Q000235:genetics / Q000378:metabolism; D009077:Mucins / Q000378:metabolism*; D009154:Mutation / Q000235:genetics; D009367:Neoplasm Staging; D009687:Nuclear Proteins / Q000378:metabolism; D016133:Polymerase Chain Reaction; D011379:Prognosis; D011446:Prospective Studies; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D055752:Small Cell Lung Carcinoma / Q000175:diagnosis / Q000235:genetics / Q000378:metabolism; D015996:Survival Rate; D000074482:Thyroid Nuclear Factor 1; D015534:Trans-Activators / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism; D025521:Tumor Suppressor Proteins / Q000378:metabolism
chemical_list: D014408:Biomarkers, Tumor; D004273:DNA, Neoplasm; D053555:Keratin-5; D053553:Keratin-6; D009077:Mucins; C000614412:NKX2-1 protein, human; D009687:Nuclear Proteins; C115051:TP63 protein, human; D000074482:Thyroid Nuclear Factor 1; D015534:Trans-Activators; D014157:Transcription Factors; D025521:Tumor Suppressor Proteins; C512478:EGFR protein, human; D066246:ErbB Receptors