title: Detection of minimal gastric cancer cells in peritoneal washings by focused microarray analysis with multiple markers: clinical implications.
abstract: BACKGROUND
  Peritoneal cytology is an important prognostic factor of gastric cancer. However, peritoneal cytology requires great skill, which may explain its low prevalence. A reverse transcriptase-polymerase chain reaction-based assay with multiple marker genes or immunocytochemistry was assessed as an alternative method of gathering the same kind of data as cytology.
  
  
  METHODS
  Peritoneal washings from 179 patients with gastric cancer were analyzed by multiplex reverse transcriptase-polymerase chain reaction with 10 marker genes and subsequent hybridization to a customized oligo-nucleotide array. Results with this assay were either validated as a prognostic factor or confirmed by demonstrating the presence of cancer cells by immunocytochemical cytology.
  
  
  RESULTS
  Only 1 (2.2%) of 44 disease-free cases was shown to be positive by the microarray assay, whereas 13 (93%) of 14 conventional cytology-positive cases were found to be positive. This assay further detected approximately one-third of cytology-negative patients either with peritoneal recurrence (7 of 20, 35%) or with non-peritoneal recurrence (6 of 22, 27%). A high concordance between the microarray assay and immunocytochemical cytology with five antibodies against CK20, FABP1, MUC2, TFF1, and MASPIN was confirmed. The clinical outcome of the microarray assay-positive cases was poor, as was that of the cytology-positive cases.
  
  
  CONCLUSIONS
  Our assay, though time-consuming and requiring special equipment, demonstrated a specificity and sensitivity equal to or better than cytology in our institutes. The minimal free peritoneal cancer cells detected by the microarray assay may provide the same clinical information as larger amounts of cancer cells for patients with gastric cancer. An anti-MASPIN antibody may be helpful in peritoneal cytology of gastric cancer.
authors.affiliation: Department of Gastrointestinal Surgery, University of Tokyo Graduate School of Medicine, Hongo 7-3-1, Bunkyo-ku, Tokyo, 113-8655, Japan.
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Mori
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Suzuki
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Uozaki
authors.forename: Hayao
authors.initials: H
authors.lastname: Nakanishi
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Ueda
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Matsuno
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Kodera
authors.forename: Hiromi
authors.initials: H
authors.lastname: Sakamoto
authors.forename: Nobuko
authors.initials: N
authors.lastname: Yamamoto
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Sasako
authors.forename: Michio
authors.initials: M
authors.lastname: Kaminishi
authors.forename: Hiroki
authors.initials: H
authors.lastname: Sasaki
mesh_terms: D014408:Biomarkers, Tumor / Q000235:genetics*; D003581:Cytodiagnosis; D050556:Fatty Acid-Binding Proteins / Q000235:genetics / Q000378:metabolism; D020869:Gene Expression Profiling; D005819:Genetic Markers; D006801:Humans; D053554:Keratin-20 / Q000235:genetics / Q000378:metabolism; D055262:Mucin-2; D009077:Mucins / Q000235:genetics / Q000378:metabolism; D009364:Neoplasm Recurrence, Local / Q000175:diagnosis; D020411:Oligonucleotide Array Sequence Analysis; D010533:Peritoneal Lavage; D010534:Peritoneal Neoplasms / Q000175:diagnosis* / Q000556:secondary; D011379:Prognosis; D012333:RNA, Messenger / Q000235:genetics; D012334:RNA, Neoplasm / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015843:Serpins / Q000235:genetics / Q000378:metabolism; D013274:Stomach Neoplasms / Q000175:diagnosis* / Q000235:genetics* / Q000473:pathology; D000071163:Trefoil Factor-1; D025521:Tumor Suppressor Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D014408:Biomarkers, Tumor; C493319:FABP1 protein, human; D050556:Fatty Acid-Binding Proteins; D005819:Genetic Markers; C507499:KRT20 protein, human; D053554:Keratin-20; C524625:MUC2 protein, human; D055262:Mucin-2; D009077:Mucins; D012333:RNA, Messenger; D012334:RNA, Neoplasm; C085344:SERPIN-B5; D015843:Serpins; C051838:TFF1 protein, human; D000071163:Trefoil Factor-1; D025521:Tumor Suppressor Proteins