title: Analysis of Histologic Features Suspecting Anaplastic Lymphoma Kinase (ALK)-Expressing Pulmonary Adenocarcinoma.
abstract: BACKGROUND
  Since 2007 when anaplastic lymphoma kinase (ALK) rearrangements were discovered in non-small cell lung cancer, the ALK gene has received attention due to ALK-targeted therapy, and a notable treatment advantage has been observed in patients harboring the EML4/ALK translocation. However, using ALK-fluorescence in situ hybridization (FISH) as the standard method has demerits such as high cost, a time-consuming process, dependency on interpretation skill, and tissue preparation. We analyzed the histologic findings which could complement the limitation of ALK-FISH test for pulmonary adenocarcinoma.
  
  
  METHODS
  Two hundred five cases of ALK-positive and 101 of ALK-negative pulmonary adenocarcinoma from January 2007 to May 2013 were enrolled in this study. The histologic findings and ALK immunohistochemistry results were reviewed and compared with the results of ALK-FISH and EGFR/KRAS mutation status.
  
  
  RESULTS
  Acinar, cribriform, and solid growth patterns, extracellular and intracellular mucin production, and presence of signet-ring-cell element, and psammoma body were significantly more often present in ALK-positive cancer. In addition, the presence of goblet cell-like cells and presence of nuclear inclusion and groove resembling papillary thyroid carcinoma were common in the ALK-positive group.
  
  
  CONCLUSIONS
  The above histologic parameters can be helpful in predicting ALK rearranged pulmonary adenocarcinoma, leading to rapid FISH analysis and timely treatment.
authors.affiliation: Department of Pathology, Soonchunhyang University Seoul Hospital, Soonchunhyang University College of Medicine, Seoul, Korea.
authors.forename: In Ho
authors.initials: IH
authors.lastname: Choi
authors.affiliation: Department of Pathology, Soonchunhyang University Seoul Hospital, Soonchunhyang University College of Medicine, Seoul, Korea.
authors.forename: Dong Won
authors.initials: DW
authors.lastname: Kim
authors.affiliation: Department of Pathology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Sang Yun
authors.initials: SY
authors.lastname: Ha
authors.affiliation: Department of Pathology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Yoon-La
authors.initials: YL
authors.lastname: Choi
authors.affiliation: Department of Pathology, Gwangmyeong Sungae Hospital, Gwangmyeong, Korea.
authors.forename: Hee Jeong
authors.initials: HJ
authors.lastname: Lee
authors.affiliation: Department of Pathology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Joungho
authors.initials: J
authors.lastname: Han
keywords: Adenocarcinoma; Anaplastic large cell lymphoma kinase; Anaplastic lymphoma kinase; Lung; in situ hybridization, fluorescence