title: p63 and TTF-1 immunostaining. A useful marker panel for distinguishing small cell carcinoma of lung from poorly differentiated squamous cell carcinoma of lung.
abstract: We studied the usefulness of p63 and thyroid transcription factor-1 (TTF-1) immunostains for differentiating poorly differentiated squamous cell carcinoma (PDSCC) from small cell lung carcinoma (SCLC). We used monoclonal antibodies reactive to p63 or TTF-1 to stain 4-microns-thick sections from 30 formalin-fixed, paraffin-embedded lung biopsy and resection specimens and 7 alcohol-fixed, formalin-postfixed, paraffin-embedded cell blocks from lung fine-needle aspirations (FNAs). For p63, we used a streptavidin-biotin kit, diaminobenzidine as the chromogen, and a hematoxylin counterstain. We used automated immunostaining for TTF-1. The 37 cases included 23 SCLCs, 13 PDSCCs, and 1 carcinoma initially diagnosed as PDSCC. All 23 SCLCs were negative or, rarely, equivocal for p63; 20 (87%) of 23 were TTF-1+; nuclear staining ranged from strong and/or frequent to weak and/or uncommon. All 13 PDSCCs were TTF-1-/p63+ with intense staining of 50% to 100% of tumor cells. One case originally diagnosed as PDSCC was TTF-1+/p63-, suggestive of SCLC; after morphologic reexamination and immunostaining for neuroendocrine markers, it was reclassified as intermediate-type SCLC. TTF-1 immunostaining showed equal or increased sensitivity in alcohol-fixed cytologic cell block samples compared with formalin-fixed biopsy material; in 1 SCLC case, the biopsy specimen was TTF-1-; however, the FNA cell block stained positively. p63 and TTF-1 appear to be useful for differentiating SCLC from lung PDSCC in formalin-fixed and alcohol-fixed, formalin-postfixed material.
authors.affiliation: Department of Pathology, Mount Sinai School of Medicine, New York, NY, USA.
authors.forename: Maoxin
authors.initials: M
authors.lastname: Wu
authors.forename: Beverly
authors.initials: B
authors.lastname: Wang
authors.forename: Joan
authors.initials: J
authors.lastname: Gil
authors.forename: Edmond
authors.initials: E
authors.lastname: Sabo
authors.forename: Lorraine
authors.initials: L
authors.lastname: Miller
authors.forename: Li
authors.initials: L
authors.lastname: Gan
authors.forename: David E
authors.initials: DE
authors.lastname: Burstein
mesh_terms: D000911:Antibodies, Monoclonal; D018288:Carcinoma, Small Cell / Q000175:diagnosis*; D002294:Carcinoma, Squamous Cell / Q000175:diagnosis*; D004268:DNA-Binding Proteins; D003937:Diagnosis, Differential; D016147:Genes, Tumor Suppressor; D006801:Humans; D007150:Immunohistochemistry; D008175:Lung Neoplasms / Q000175:diagnosis*; D008565:Membrane Proteins; D009687:Nuclear Proteins / Q000032:analysis*; D016612:Paraffin Embedding; D010750:Phosphoproteins / Q000032:analysis*; D000074482:Thyroid Nuclear Factor 1; D015534:Trans-Activators / Q000032:analysis*; D014157:Transcription Factors / Q000032:analysis*; D025521:Tumor Suppressor Proteins
chemical_list: D000911:Antibodies, Monoclonal; C081876:CKAP4 protein, human; D004268:DNA-Binding Proteins; D008565:Membrane Proteins; C000614412:NKX2-1 protein, human; D009687:Nuclear Proteins; D010750:Phosphoproteins; C115051:TP63 protein, human; D000074482:Thyroid Nuclear Factor 1; D015534:Trans-Activators; D014157:Transcription Factors; D025521:Tumor Suppressor Proteins