title: Differential expression of telomerase activity in neuroendocrine lung tumours: correlation with gene product immunophenotyping.
abstract: Telomerase activity was examined by the telomeric repeat amplification protocol (TRAP) assay in 38 neuroendocrine (NE) lung tumours. A significantly (p = 0.001) different frequency of telomerase positivity was observed among different histological tumour types. Specifically, a positive TRAP signal was observed in 14 of 15 (93%) small cell lung cancers (SCLCs), 7 of 8 (87%) large-cell NE carcinomas (LCNECs), and only 1 of 15 (7%) typical carcinoid tumours. When telomerase activity was correlated with the gene product-based immunophenotypic profile of individual tumours, it was found that the absence of telomerase activity was associated with a lack of bcl-2, p53, and c-kit expression, and characterized by a low proliferation index consistent with the absence of cdk-4 expression and the presence of the cdk inhibitor Rb. Such a phenotype was appreciable in most of the carcinoid tumours. Conversely, telomerase-positive tumours generally showed an immunophenotype consistent with gene product alterations (including high expression of bcl-2, p53, and c-kit, and loss of Rb) and were characterized by a high proliferation index. These telomerase data support the previously reported evidence for two genetically unrelated groups of NE lung tumours (SCLC, and to some extent LCNEC, versus carcinoid tumours) that have distinct phenotypic profiles.
authors.affiliation: Department of Experimental Oncology, Istituto Nazionale per la Studio e la Cura dei Tumori, Milan, Italy.
authors.forename: Nadia
authors.initials: N
authors.lastname: Zaffaroni
authors.forename: Daniela
authors.initials: D
authors.lastname: De Polo
authors.forename: Raffaella
authors.initials: R
authors.lastname: Villa
authors.forename: Chiara
authors.initials: C
authors.lastname: Della Porta
authors.forename: Paola
authors.initials: P
authors.lastname: Collini
authors.forename: Alessandra
authors.initials: A
authors.lastname: Fabbri
authors.forename: Silvana
authors.initials: S
authors.lastname: Pilotti
authors.forename: Maria Grazia
authors.initials: MG
authors.lastname: Daidone
mesh_terms: D014408:Biomarkers, Tumor / Q000378:metabolism; D002276:Carcinoid Tumor / Q000201:enzymology / Q000276:immunology / Q000473:pathology; D002289:Carcinoma, Non-Small-Cell Lung / Q000201:enzymology / Q000276:immunology / Q000473:pathology; D018288:Carcinoma, Small Cell / Q000201:enzymology / Q000276:immunology / Q000473:pathology; D002455:Cell Division; D006801:Humans; D016130:Immunophenotyping; D008175:Lung Neoplasms / Q000201:enzymology* / Q000276:immunology / Q000473:pathology; D009363:Neoplasm Proteins / Q000378:metabolism; D018358:Neuroendocrine Tumors / Q000201:enzymology* / Q000276:immunology / Q000473:pathology; D019098:Telomerase / Q000378:metabolism*
chemical_list: D014408:Biomarkers, Tumor; D009363:Neoplasm Proteins; D019098:Telomerase