Detection of micrometastases in peritoneal washings of gastric cancer patients by the reverse transcriptase polymerase chain reaction.
BACKGROUND
Gastric cancer patients with positive (+) peritoneal cytology have a prognosis similar to stage IV patients. We studied the ability of quantitative reverse transcriptase polymerase chain reaction (RT-PCR) to detect peritoneal micrometastases in patients undergoing staging laparoscopy.


METHODS
Peritoneal washings were obtained prospectively from 34 patients with gastric adenocarcinoma undergoing staging laparoscopy and 6 patients undergoing laparoscopy for benign disease. Each sample underwent cytologic and RT-PCR analysis for tumor markers: carcinoembryonic antigen (CEA), cytokeratin 20 (CK20), survivin, and MUC2. Markers were evaluated on the basis of their deviance from the ideal marker.


RESULTS
Pathologic stages for the gastric cancer patients were: stage I, 9 (27%); stage II, 7 (21%); stage III, 15 (44%); and stage IV, 3 (9%). The four cytology (+) patients were: stage II, 1; stage III, 1; and stage IV, 2. Fifteen patients were RT-PCR (+), including all cytology (+) patients. The optimal threshold for cycle amplification was 35, based on a receiver operating characteristic curve. CEA had the smallest deviance.


CONCLUSIONS
RT-PCR using a panel of tumor markers, including CEA, detects (+) cytology. The clinical significance of "false-positive" overexpression of CEA, survivin, or CK20 but cytology (-) remains to be defined. RT-PCR could represent a more sensitive method than cytology for detection of subclinical peritoneal tumor dissemination; this may be useful in improving patient selection for operative management and clinical trials.
Dalal
Kimberly Moore
KM
Department of Surgery, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York NY, 10021, USA.
Woo
Yanghee
Y
Kelly
Kaitlyn
K
Galanis
Charles
C
Gonen
Mithat
M
Fong
Yuman
Y
Coit
Daniel G
DG
D000230:Adenocarcinoma / Q000473:pathology / Q000556:secondary*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000032:analysis; D002272:Carcinoembryonic Antigen / Q000032:analysis; D005260:Female; D006801:Humans; D051034:Inhibitor of Apoptosis Proteins; D053554:Keratin-20 / Q000032:analysis; D010535:Laparoscopy; D008297:Male; D008869:Microtubule-Associated Proteins / Q000032:analysis; D008875:Middle Aged; D055262:Mucin-2 / Q000032:analysis; D009367:Neoplasm Staging; D010529:Peritoneal Cavity / Q000473:pathology*; D010534:Peritoneal Neoplasms / Q000175:diagnosis / Q000556:secondary*; D012333:RNA, Messenger / Q000032:analysis; D012372:ROC Curve; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013274:Stomach Neoplasms / Q000473:pathology*; D000077022:Survivin
C107489:BIRC5 protein, human; D014408:Biomarkers, Tumor; D002272:Carcinoembryonic Antigen; D051034:Inhibitor of Apoptosis Proteins; D053554:Keratin-20; C524625:MUC2 protein, human; D008869:Microtubule-Associated Proteins; D055262:Mucin-2; D012333:RNA, Messenger; D000077022:Survivin