title: Persistent genetic abnormalities in Barrett's esophagus after photodynamic therapy.
abstract: OBJECTIVE
  Photodynamic therapy (PDT) is a technique for nonsurgical treatment of patients with dysplasia in Barrett's esophagus. The primary endpoint for PDT has been resolution of dysplasia. We studied the effect of PDT at the genetic level.
  
  
  METHODS
  Archival material from 3 patients who had initial improvement in dysplasia after PDT but occurrence of high-grade dysplasia during follow-up was used. Biopsy specimens were analyzed for increased proliferation, aneuploidy, p53 protein overexpression, p53 mutations, and p16 promoter hypermethylation.
  
  
  RESULTS
  Patients developed high-grade dysplasia 16, 28, and 37 months after PDT. In all cases, one or more genetic markers were positive after PDT treatment, whereas histology was downstaged consistently after therapy. Increasing genetic abnormalities were noted by the end of follow-up.
  
  
  CONCLUSIONS
  Genetic abnormalities may persist after PDT despite phenotypical improvement of dysplasia. These patients may progress to high-grade dysplasia or develop adenocarcinoma. Histologic improvement in dysplasia is an inadequate endpoint for PDT in patients with Barrett's esophagus.
authors.affiliation: Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, Minnesota 55905, USA.
authors.forename: K K
authors.initials: KK
authors.lastname: Krishnadath
authors.forename: K K
authors.initials: KK
authors.lastname: Wang
authors.forename: K
authors.initials: K
authors.lastname: Taniguchi
authors.forename: T J
authors.initials: TJ
authors.lastname: Sebo
authors.forename: N S
authors.initials: NS
authors.lastname: Buttar
authors.forename: M A
authors.initials: MA
authors.lastname: Anderson
authors.forename: L S
authors.initials: LS
authors.lastname: Lutzke
authors.forename: W
authors.initials: W
authors.lastname: Liu
mesh_terms: D000368:Aged; D000782:Aneuploidy; D001471:Barrett Esophagus / Q000188:drug therapy* / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000235:genetics / Q000378:metabolism; D004947:Esophagus / Q000473:pathology; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008745:Methylation; D008875:Middle Aged; D010778:Photochemotherapy; D017354:Point Mutation / Q000235:genetics; D011401:Promoter Regions, Genetic; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism
chemical_list: D019941:Cyclin-Dependent Kinase Inhibitor p16; D016159:Tumor Suppressor Protein p53