[The clinical significance of serum anti-p53 antibody as a monitoring marker in colorectal cancer].

We examined alterations in the level of serum anti-p53 antibody(S-p53 Ab) in colorectal cancer patients who underwent curative resection and analyzed the usefulness of S-p53 Ab as a monitoring marker for postoperative observation. The measurement of S-p53 Ab was performed preoperatively and postoperatively in 16 stage II/III colorectal cancer patients with a high level of S-p53 Ab. A time course analysis of both S-p53 Ab and CEA levels was performed in 6 of these patients who were carcinoembryonic antigen (CEA) positive. The median S-p53 Ab level was 29.9 U/mL and the half-life of the S-p53 Ab level was 40.3 days. In 4(25%) cases, the level of S-p53 Ab recovered to within normal limits by 79-142 days. When the half-lives of S-p53 Ab and CEA were analyzed in 6 patients who were both S-p53 Ab and CEA positive, the half-lives of S-p53 Ab and CEA were 32.3 and 13.2 days, respectively. In the case of recurrence with liver metastasis after resection of ascending colon cancer, the S-p53 Ab level did not respond quickly while the CEA level increased. Therefore, it is difficult to use the level of S-p53 Ab as a marker for monitoring treatment, and priority should be given to the examination of CEA and imaging modality.