title: p16 Deletion in sarcomatoid tumors of the lung and pleura.
abstract: BACKGROUND
  The diagnosis of sarcomatoid neoplasms of the lung and pleura can be challenging. Homozygous deletion of 9p21, the locus harboring the p16 gene, has been reported as the most common genetic alteration in malignant mesotheliomas that is of potential diagnostic and prognostic significance.
  
  
  OBJECTIVE
  To evaluate the frequency of 9p21 deletion by fluorescence in situ hybridization in the primary sarcomatoid neoplasms of the lung and pleura and to determine its potential diagnostic utility.
  
  
  METHODS
  Ninety-two sarcomatoid neoplasms of the lung and pleura (32 sarcomatoid mesotheliomas, 15 sarcomatoid carcinomas, 32 solitary fibrous tumors, and 13 high-grade sarcomas) were examined for 9p21 deletion by fluorescence in situ hybridization.
  
  
  RESULTS
  Deletion of 9p21 was most frequently seen in malignant mesotheliomas (81%), followed by sarcomatoid carcinomas (53%), sarcomas (25%), and solitary fibrous tumors (12.5%). Malignant mesotheliomas showed mostly homozygous deletion, whereas sarcomatoid carcinomas showed either homozygous or hemizygous deletion. None of the sarcomas showed homozygous deletion. There was a trend toward more frequent occurrence of 9p21 deletion in recurrent solitary fibrous tumors, but this did not reach statistical difference.
  
  
  CONCLUSIONS
  Deletion of 9p21 is common in sarcomatoid tumors of the lung and pleura. Despite statistically significant differences in the frequency of 9p21 deletion, and because of the large overlap among the study groups, this genetic abnormality cannot be used as a reliable diagnostic tool in the assessment of sarcomatoid lesions of the lung and pleura. A potential use of p16 deletion in predicting the biology of solitary fibrous tumors should be further explored.
authors.affiliation: Department of Pathology, University of Pittsburgh Medical Center, Pittsburgh, PA 15213, USA.
authors.forename: Naobumi
authors.initials: N
authors.lastname: Tochigi
authors.forename: Richard
authors.initials: R
authors.lastname: Attanoos
authors.forename: Lucian R
authors.initials: LR
authors.lastname: Chirieac
authors.forename: Timothy Craig
authors.initials: TC
authors.lastname: Allen
authors.forename: Philip T
authors.initials: PT
authors.lastname: Cagle
authors.forename: Sanja
authors.initials: S
authors.lastname: Dacic
mesh_terms: D000328:Adult; D014408:Biomarkers, Tumor / Q000235:genetics; D019941:Cyclin-Dependent Kinase Inhibitor p16; D017353:Gene Deletion; D006801:Humans; D008175:Lung Neoplasms / Q000235:genetics* / Q000473:pathology; D008654:Mesothelioma / Q000235:genetics* / Q000473:pathology; D009363:Neoplasm Proteins / Q000235:genetics*; D010997:Pleural Neoplasms / Q000235:genetics* / Q000473:pathology; D011379:Prognosis; D012509:Sarcoma / Q000235:genetics* / Q000473:pathology
chemical_list: D014408:Biomarkers, Tumor; C000614131:CDKN2A protein, human; D019941:Cyclin-Dependent Kinase Inhibitor p16; D009363:Neoplasm Proteins