title: Use of guanylyl cyclase C for detecting micrometastases in lymph nodes of patients with colon cancer.
abstract: BACKGROUND
  Guanylyl cyclase C appears to be expressed only in colorectal cancer cells in extraintestinal tissues. Thus, guanylyl cyclase C may be useful as a marker to detect colorectal cancer micrometastases not detectable by histopathology in lymph nodes of patients.
  
  
  METHODS
  Twelve patients with colon adenocarcinoma, Dukes Stages A through C2, and one patient with a tubulovillous adenoma were included in this study. Forty-two lymph nodes were collected from fresh surgical specimens, and each was examined by histopathology and reverse transcription followed by polymerase chain reaction using guanylyl cyclase C-specific primers. Histopathology identified colon cancer cells in 6 of 16 lymph nodes from five Dukes Stage C patients but not in lymph nodes from the patient with a tubulovillous adenoma, the Dukes Stage A patient, or six Dukes Stage B patients. Reverse transcription followed by polymerase chain reaction using guanylyl cyclase C-specific primers was performed on all 42 lymph nodes.
  
  
  RESULTS
  Guanylyl cyclase C messenger RNA was not detected by reverse transcription followed by polymerase chain reaction in lymph nodes from the patient with the tubulovillous adenoma or the patient with Dukes Stage A colon carcinoma. Seven lymph nodes from Dukes Stage C patients revealed guanylyl cyclase C messenger RNA including six lymph nodes containing histopathologically confirmed metastases. Of significance, guanylyl cyclase C messenger RNA was detected in 6 of 21 lymph nodes from Dukes Stage B patients. Indeed, clinical staging of two patients could be upgraded from B to C using reverse transcription followed by polymerase chain reaction and guanylyl cyclase C-specific primers.
  
  
  CONCLUSIONS
  Reverse transcription followed by polymerase chain reaction using guanylyl cyclase C-specific primers might be useful to more accurately assess micrometastases in lymph nodes of colorectal cancer patients undergoing disease staging.
authors.affiliation: Department of Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA.
authors.forename: S A
authors.initials: SA
authors.lastname: Waldman
authors.forename: B
authors.initials: B
authors.lastname: Cagir
authors.forename: J
authors.initials: J
authors.lastname: Rakinic
authors.forename: R D
authors.initials: RD
authors.lastname: Fry
authors.forename: S D
authors.initials: SD
authors.lastname: Goldstein
authors.forename: G
authors.initials: G
authors.lastname: Isenberg
authors.forename: M
authors.initials: M
authors.lastname: Barber
authors.forename: S
authors.initials: S
authors.lastname: Biswas
authors.forename: C
authors.initials: C
authors.lastname: Minimo
authors.forename: J
authors.initials: J
authors.lastname: Palazzo
authors.forename: P K
authors.initials: PK
authors.lastname: Park
authors.forename: D
authors.initials: D
authors.lastname: Weinberg
mesh_terms: D000230:Adenocarcinoma / Q000175:diagnosis / Q000556:secondary*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000032:analysis*; D003110:Colonic Neoplasms / Q000473:pathology*; D005260:Female; D006162:Guanylate Cyclase / Q000032:analysis*; D006801:Humans; D008198:Lymph Nodes / Q000201:enzymology* / Q000473:pathology; D008207:Lymphatic Metastasis / Q000175:diagnosis* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D016133:Polymerase Chain Reaction; D011379:Prognosis; D011446:Prospective Studies; D000074261:Receptors, Enterotoxin; D050705:Receptors, Guanylate Cyclase-Coupled; D018000:Receptors, Peptide / Q000032:analysis*
chemical_list: D014408:Biomarkers, Tumor; D018000:Receptors, Peptide; D006162:Guanylate Cyclase; D000074261:Receptors, Enterotoxin; D050705:Receptors, Guanylate Cyclase-Coupled