Detection of serum p53 protein in patients with different gastrointestinal cancers.

Overexpression of p53 has been found in many types of human malignancy. The present study aimed to detect preoperative serum p53 among 158 patients with different gastrointestinal cancers using ELISA technique based on mouse anti-p53 DO-7 monoclonal antibody and anti-p53 rabbit polyclonal antibody. A single band of 53kDa was detected in nuclear protein tissue extracts of selected cancer patients and in 96% of the corresponding sera using Western blot assay. The ELISA technique revealed that the serum p53 was detected in 100% of patients with cholangiocarcinoma, 76% of pancreatic carcinoma, 75% of hepatocellular carcinoma, 70% of colon cancer, 60% of esophagus carcinoma, and 35% of gastric carcinoma. The serum p53 concentrations of the positive patients were highly elevated (P<0.001) compared with healthy individuals. These results suggest that immunodetection of serum p53 could be valuable for post-operative monitoring during follow up in preoperatively positive patients with gastrointestinal cancers.