Usefulness of serum p53 antibody measurement in colorectal cancer: an examination of 1384 primary colorectal cancer patients

Recently, the serum p53 antibody (S-p53Ab) has been used widely in clinical practice as a tumor marker for colorectal cancer (CRC). However, no large-scale studies have examined the usefulness of serial measurements of S-p53Ab or have established the relationship of this parameter with the clinicopathological factors of CRC. An ELISA for S-p53Ab was performed for 1384 primary CRC patients, and the results were categorized by the clinicopathological factors. The S-p53Ab positivity rate was 24.1 %, and was significantly higher in Stage III-IV than in Stage 0-II cases. However, no relationship was seen with the serum carcinoembryonic antigen (CEA) or carbohydrate antigen 19-9 (CA19-9) levels. The addition of the S-p53Ab assay to the CEA and CA19-9 measurements increased the overall diagnostic sensitivity to 50.9 % (CEA and/or CA19-9: 37.3 %). In patients who had undergone complete resection, S-p53Ab positivity was associated with a decrease in the relapse-free survival (p = 0.012), but it was not independent prognostic indicator. S-p53Ab positivity had no influence on the cancer-specific survival. The S-p53Ab positivity rate was higher than the positivity rates for CEA and/or CA19-9 in Stage 0-I CRC patients. Combining the use of the three tumor marker tests is a potentially effective method for detecting even early-stage CRC.