title: Sarcomatoid adenocarcinoma of the lung: clinicopathological, immunohistochemical and molecular analyses.
abstract: BACKGROUND
  Biphasic lung cancers with admixtures of adenocarcinoma and sarcomatoid components but lacking true mesenchymal differentiation (sarcomatoid adenocarcinomas) are rare, and extensive studies of their clinicopathological characteristics and histogenesis have not been performed.
  
  
  METHODS
  Six surgically resected sarcomatoid adenocarcinomas were compared clinicopathologically with 317 standard adenocarcinomas, and studied immunohistochemically and by loss of heterozygosity (LOH) analysis focusing on each component.
  
  
  RESULTS
  In comparison with standard adenocarcinomas, the sarcomatoid adenocarcinomas occurred in older patients, were more likely to be associated with smoking and were more acinar than papillary, with a worse five-year prognosis. Immunohistochemically, sarcomatoid components were positive for epithelial markers in three cases. In one case the carcinoma showed retention of heterozygosity and the sarcomatoid components allelic loss, while all other cases showed retention or LOH in both components.
  
  
  CONCLUSIONS
  The sarcomatoid adenocarcinoma exhibits different clinicopathological characteristics from standard adenocarcinomas. The present immunohistochemical and LOH analyses provided support for the idea that both components are derived from one precursor cell, and that progression may be by way of adenocarcinoma to sarcomatoid differentiation.
authors.affiliation: Department of Pathology, Saitama Cancer Center, 818 Komuro, Ina, Kita-adachi-gun, Saitama 362-0806, Japan.
authors.forename: Kazunori
authors.initials: K
authors.lastname: Nishida
authors.forename: Yasuhito
authors.initials: Y
authors.lastname: Kobayashi
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Ishikawa
authors.forename: Yukitoshi
authors.initials: Y
authors.lastname: Satoh
authors.forename: Sakae
authors.initials: S
authors.lastname: Okumura
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Nishimura
authors.forename: Ken
authors.initials: K
authors.lastname: Nakagawa
authors.forename: Kyoichi
authors.initials: K
authors.lastname: Nakamura
authors.forename: Morio
authors.initials: M
authors.lastname: Koike
authors.forename: Eiju
authors.initials: E
authors.lastname: Tsuchiya
mesh_terms: D000230:Adenocarcinoma / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D000368:Aged; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D019656:Loss of Heterozygosity; D008175:Lung Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D012509:Sarcoma / Q000235:genetics / Q000378:metabolism / Q000473:pathology*