Golgi protein 73 (gp73) is a useful tumor marker in patients with colon cancer.

Abstract

e14089 Background: Golgi protein 73 (gp73) is a 400 kD trans-membrane protein expressed in hepatocytes when induced by cytokines or exposed to viruses. Gp73 is also expressed in various tumor cells including colon cancer. In this study, we aimed to evaluate the value of the serum gp73 as a tumor marker in patients with colon cancer. Methods: A total of 126 patients with liver only metastases, with non-liver metastases, without distant metastasis (both preoperative and postoperative period), and a group of colon cancer patients in remission at least 3 years and not relapsed within at least 6 months after obtaining blood samples and a healthy group with similar age and gender were included in the study. The serum gp73 levels were measured by ELISA and compared with serum CEA and CA 19.9 levels. Results: Serum gp73 was higher than the lower detection limit of the test in the majority of the test subjects. The diagnostic performance of gp73 was better than both CEA and CA19.9 for colon cancer metastases (AUC= 0.974±0.003 [95%CI: 0.912-1.037] for gp73; AUC=0.859±0.089 [95%CI: 0.684-1.034] for CEA; and AUC=0.782±0.106 [95%CI: 0.574-0.990] for CA19.9) (p<0.05). The diagnostic performance of gp73 as a tumor marker was especially more prominent in the subgroup of liver only metastases. For the non-liver metastases, the performance of CEA was similar to gp73. At the cut-off level of 15 ng/mL, the sensitivity of gp73 was 80% and specificity 100%. The sensitivity and specificity of CEA were 72% and 100% at the level of 5 ng/mL and of CA 19.9 69% and 100% at the level of 45 U/mL. Conclusions: The serum gp73 seems to be a useful tumor marker in patients with colon cancer.