title: Impact of non-small-cell lung cancer-not otherwise specified immunophenotyping on treatment outcome.
abstract: BACKGROUND
  The vast majority of non-small-cell lung cancers (NSCLCs) presents as advanced disease, and histological diagnosis is widely based on small samples. The differential activity and toxicity profile of new cytotoxic and molecular-targeted therapies according to histotypes requires a precise subtyping of NSCLC. Immunohistochemistry (IHC) contributes to define the most probable histotype; however, the real impact of IHC characterization of NSCLC-not otherwise specified (NOS) in terms of outcome is not well established.
  
  
  METHODS
  A large series of 224 advanced "nonsquamous" NSCLC diagnosed on small biopsy or cytological samples and homogeneously treated was retrospectively selected, all having adequate follow-up data available. Reviewed diagnoses resulted into two groups: adenocarcinoma (ADC) and NSCLC-NOS. The latter was further characterized by IHC (TTF-1, Napsin-A, p40, and Desmocollin-3) -identify a possible, most probable differentiation lineage.
  
  
  RESULTS
  Sixty-seven percentage of cases were classified as ADC based on morphological examination only ("morphological ADC") and 33% as NSCLC-NOS. IHC profiling of NSCLC-NOS identified 43.2% of cases with an ADC immunophenotype ("NSCLC favor ADC"), 10.8% with a phenotype favoring squamous lineage, and 46% lacking differentiation features. Survival curves confirmed no difference in terms of outcome between the morphological ADC and the NSCLC favor ADC groups, while a significantly poorer outcome was found in the "null" group in terms of best response, progression-free survival or overall survival (OS).
  
  
  CONCLUSIONS
  Tumors with an IHC profile ADC-like had an OS comparable with that of morphological ADCs. These findings support the use of IHC to optimize lung cancer histological typing and therapy.
authors.affiliation: *Department of Oncology, University of Turin at San Luigi Hospital, Orbassano, Torino; and †Division of Pathology, University of Modena, Modena, Italy.
authors.forename: Luisella
authors.initials: L
authors.lastname: Righi
authors.forename: Tiziana
authors.initials: T
authors.lastname: Vavalà
authors.forename: Ida
authors.initials: I
authors.lastname: Rapa
authors.forename: Simona
authors.initials: S
authors.lastname: Vatrano
authors.forename: Jessica
authors.initials: J
authors.lastname: Giorcelli
authors.forename: Giulio
authors.initials: G
authors.lastname: Rossi
authors.forename: Enrica
authors.initials: E
authors.lastname: Capelletto
authors.forename: Silvia
authors.initials: S
authors.lastname: Novello
authors.forename: Giorgio V
authors.initials: GV
authors.lastname: Scagliotti
authors.forename: Mauro
authors.initials: M
authors.lastname: Papotti
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002289:Carcinoma, Non-Small-Cell Lung / Q000145:classification / Q000188:drug therapy / Q000276:immunology* / Q000473:pathology; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D016130:Immunophenotyping; D008175:Lung Neoplasms / Q000145:classification / Q000188:drug therapy / Q000276:immunology* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D016896:Treatment Outcome