Background: An important goal of serum tumor marker research is to provide a test for detecting cancer in early stages. Expression of carbohydrate antigen (CA) 19.9 has been described in various malignancies.
Methods: The possible prognostic value measuring cytosol CA 19.9 expression in tumors was evaluated in a study of 63 colorectal carcinoma (CRC) patients who were followed for at least 2 years. CA 19.9 expression in cytosol was determined by enzyme-linked immunoadsorbant assay, and measurement of this protein achieved by quantitative assay.
Results: Mean levels of cytosol CA 19.9 found in tumor samples were significantly higher than those in nontumoral areas in CRC patients (P<0.0005). Patients with more than 3 positive lymph nodes had a higher expression of the marker (P<0.05). Univariate and multivariate analyses revealed that cytosol CA 19.9 concentration was an independent prognostic variable for relapse. Furthermore, the probability of relapse increased 4.2 times for every increase in cytosol tumor marker of 5000 U/mg, and tumors located in the rectum had a probability of relapse 9.5 times greater.
Conclusions: Cystol CA 19.9 expression in CRC can be an independent prognostic factor for relapse. Patients with high levels of CA 19.9 have worse prognosis than those with lower values. Therefore, this group of patients should receive special management with regard to their follow-up and treatment. Moreover, quantitative cytosol tumor marker measurement is an easy and highly effective method for determining the prognoses of CRC patients.
Copyright 1999 American Cancer Society.