To investigate the relationship between the presence of
circulating tumor cells in different stages of
gastrointestinal tract cancer and the subsequent relapse or distant
metastasis, circulating levels of CEA
mRNA was serially examined at an interval of 10.6+/-4.5 or 13.7+/-3.0 months in gastric or
colorectal cancer patients, respectively. CEA
mRNA was measured by means of RT-PCR amplification as an
indicator for micrometastatic malignant cells. Seven of twenty-nine respectable
gastric cancer patients (24.1%) [EGC: 2/9 (22.2%), AGC IIIa: 1/5 (20.0%), AGC IIIb: 4/15 (26.6%)] were positive for CEA
mRNA on the initial test and 10 of 29 patients (34.4%) [EGC: 2/ 9 (22.2%), AGC IIIa: 1/5 (20.0%), AGC IIIb: 7/15 (46.7%)] were positive on a follow-up test. Only in AGC IIIb, the positive rate for CEA
mRNA increased about twice and 6 of 7 positive cases (85.7%) relapsed within 2.6+/-2.4 months after the follow-up test. In
colorectal cancer, 4 of 19 patients (21.1%) [B2: 1/6 (16.7%), C2: 3/13 (23.0%)] were positive on the initial test and 10 of 19 patients (52.6%) [B2: 4/6 (66.7%), C2: 6/13 (46.2%)] were positive on a follow-up test showing an increase in positive rates during a follow-up, however, no significant correlation between CEA
mRNA positivity and subsequent relapse was demonstrated. These results suggest that an early
tumor cell dissemination may occur in
gastrointestinal tract cancer without subsequent relapse, however, the serial regular examination of CEA
mRNA level may contribute to predicting a subsequent relapse in AGC IIIb in
gastric cancer.