title: Role of imaging biomarkers in predicting anaplastic lymphoma kinase-positive lung adenocarcinoma.
abstract: OBJECTIVE
  For the ultimately efficient screening of anaplastic lymphoma kinase gene (ALK)-positive cases, combination of radiometabolic characteristics with clinicopathologic features may be more useful. Therefore, we determined radiologic characteristics and metabolic characteristics in patients with adenocarcinoma harboring ALK mutations.
  
  
  METHODS
  We retrospectively reviewed clinicopathologic CT and PET/CT data from patients with advanced lung adenocarcinoma screened for identifying ALK rearrangement. Lesion size, solidity, location, margins, CT attenuation, and SUVmax were assessed. Pathologic features such as differentiation, the presence of signet ring cell, EGFR/KRAS mutation status, and TTF-1 expression were also reviewed.
  
  
  RESULTS
  Of the screened 221 patients, 41 patients (19%) demonstrated ALK rearrangements, and these individuals were younger than the ALK-negative patients (P < 0.001) and showed significant association with no exposure to tobacco (P = 0.028). ALK-positive lung adenocarcinomas were significantly less differentiated than those without rearrangements (P = 0.005). ALK-positive tumors showed significantly higher SUVmax than ALK-negative tumors (P = 0.016). Multivariate logistic regression modeling for predicting the ALK-positive lung adenocarcinoma disclosed that lower CT attenuation and higher SUVmax were significant independent factors of ALK rearrangements (odds ratio, 0.87 and 1.06; P = 0.03 and 0.01, respectively). Receiver operating characteristic analysis showed that the area under the receiver operating characteristic curve for SUVmax/CT attenuation ratio was 0.788, and the optimal cutoff value of SUVmax/CT attenuation ratio for identifying ALK-positive lung adenocarcinoma was greater than or equal to 0.208 (sensitivity, 74.2%; specificity, 81.0%).
  
  
  CONCLUSIONS
  This study shows that ALK-rearranged lung adenocarcinoma represents younger age, no history of smoking, the absence of spiculation on CT, and higher SUVmax/CT attenuation greater than or equal to 0.208 compared with those without ALK mutation.
authors.affiliation: From the Departments of *Radiology and Center for Imaging Science, and †Pathology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul; ‡Department of Pathology, Kyungpook National University Medical Center, Kyungpook National University School of Medicine, Daegu; and §Department of Nuclear Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea.
authors.forename: Chae Jin
authors.initials: CJ
authors.lastname: Jeong
authors.forename: Ho Yun
authors.initials: HY
authors.lastname: Lee
authors.forename: Joungho
authors.initials: J
authors.lastname: Han
authors.forename: Ji Yun
authors.initials: JY
authors.lastname: Jeong
authors.forename: Kyung Soo
authors.initials: KS
authors.lastname: Lee
authors.forename: Yoon-La
authors.initials: YL
authors.lastname: Choi
authors.forename: Joon Young
authors.initials: JY
authors.lastname: Choi
mesh_terms: D000230:Adenocarcinoma / Q000000981:diagnostic imaging* / Q000235:genetics / Q000473:pathology; D000077192:Adenocarcinoma of Lung; D000328:Adult; D000368:Aged; D000077548:Anaplastic Lymphoma Kinase; D014408:Biomarkers, Tumor / Q000235:genetics*; D016022:Case-Control Studies; D005260:Female; D019788:Fluorodeoxyglucose F18; D015321:Gene Rearrangement; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000235:genetics / Q000473:pathology; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals; D020794:Receptor Protein-Tyrosine Kinases / Q000235:genetics*; D014057:Tomography, X-Ray Computed
chemical_list: D014408:Biomarkers, Tumor; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; C000626173:ALK protein, human; D000077548:Anaplastic Lymphoma Kinase; D020794:Receptor Protein-Tyrosine Kinases