Exponential decreases in Carcinoembryonic Antigen (CEA) levels of 44 patients were monitored. These patients received surgery for gastric or colon cancers, and their CEA levels were very high before surgery. twenty-five patients who had no recurrence for 1 or more years showed constant decrease of CEA levels with 4 to 5 day half life periods until the level reached the normal range. On the other hand, the lines or curves of CEA decreases obtained for 13 of the 19 patients who had recurrences, showed dissociation from the theoretical line of the half life period before the level decreased to the normal range. We understood that this dissociation was caused by the growth of residual cancers.
We concluded that a much earlier detection of remaining cancer and an earlier prediction of recurrence is possible by detecting the dissociation of the actual decrease in CEA levels from the half life period line.

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The immunoreactivity of ras p21 protein product (p21) was examined in 66 freshly obtained colorectal cencer tissues and in 75 normal colon mucosa using the anti-v-H-ras p21 monoclonal antibody (Y13-259). The aim of this study was to define the clinical significance of overexpression of p21 for colorectal carcinoma. Positive staining (overexpression) of p21 was detected in 33 out of 66 cancer tissues, whereas only 7 out of 75 samples from normal colon mucosa stained positively. The difference was significant (p<0.01). There was no correlation between the overexpression of p21 and the clinical stages of colo-rectal adenocarcinomas. Survival of patients or recurrence of the disease did not differ between 33 patients with tumors stained positively for p21 and 33 patients with tumors showing negative immunoreacitivity.
These results suggested that the overexpression of p21 is implicated in malignant transformation of colorectal mucosa, but has no prognostic singnificance for patients with colorectal adenocarcinoma.

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We investigated whether HLA antigens could act as predictors of the response to therapy in gastric cancer.
The microcytotoxicity assay was used to examine HLA antigens of the A, B, and C loci in 429 patients who underwent gastric cancer resection. HLA antigens were then divided four categories after quantifying the response pattern. To evaluate the prognostic factors, multivariate analysis using Cox's model was performed in 321 patients using seven variables: sex, age, pTNM stage, postoperative adjuvant therapy, HLA category, and the association of HLA category with the response to postoperative therapy. Patients received either gastrectomy alone, gastrectomy plus chemotherapy, or gastrectomy plus PSK ± chemotherapy. The Cox's analysis indicated that HLA Category 4 patients receiving PSK ± chemotherapy had a better prognosis than those of HLA categories 1, 3, and 4 receiving gastrectomy alone or those of HLA category 1 receiving chemotherapy after gastrectomy.
These results suggest that HLA antigen status can predict the response to therapy and that rational individualized therapy for cancer patients may possibly be designed in the future by evaluating HLA antigens.

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Patients with colorectal carcinoma were treated with UFT and Tegafur for 7 days repeated (600mg per day), and 5-FU concentrations in tissues and inhibition rate of Thymidylate Synthase (TS) were compared. As a control, total amounts of TS were determined in tissues from patients who did not receive any drug. Total amounts of TS were compared between UFT or Tegafur group and control group.
Both 5-FU concentration and inhibition rate of TS in tumor tissues were significantly higher in UFT group than Tegafur group.
Total amounts of TS in tumor tissues, normal mucous membranes, and lymph nodes were significantly higher in patients treated with drugs than patients who did not receive any drug. Particularly, high level of TS was induced in patients treated with UFT. Relationship between total TS in tumor tissues and inhibition rate of TS were then studied. Inhibition rate of TS remained 50 to 60% regardless of total TS.

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