Use of guanylyl cyclase C for detecting micrometastases in lymph nodes of patients with colon cancer.
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.
Waldman
S A
SA
Department of Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA.
Cagir
B
B
Rakinic
J
J
Fry
R D
RD
Goldstein
S D
SD
Isenberg
G
G
Barber
M
M
Biswas
S
S
Minimo
C
C
Palazzo
J
J
Park
P K
PK
Weinberg
D
D
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*
D014408:Biomarkers, Tumor; D018000:Receptors, Peptide; D006162:Guanylate Cyclase; D000074261:Receptors, Enterotoxin; D050705:Receptors, Guanylate Cyclase-Coupled