Application of molecular epidemiological biomarkers by monitoring the effects of treatment in colorectal cancer during follow-up study

Aim. We tested the applicability of expression of onco/tumor suppressor genes as biomarkers for monitoring the therapeutical efficacy of colorectal cancer, and compared it with traditional tumor markers (CA19-9 and CEA) and with the total blood antioxidant capacity. Materials and methods. In our follow-up study the expression of oncogenes and tumor suppressor genes of colorectal cancer patients was examined from peripheral blood. The expression of c-myc, Ha-ras, Bcl-2 oncogene and p53 tumor suppressor gene was measured and compared to the level of classical tumor markers, such as CA19-9 and CEA, and the antioxidant capacity in the blood was measured as well. The tests were performed on the day of surgery, on the seventh postoperative day, and after 3, 6, 12 months. Twenty patients, with locally advanced disease took part in the study. Neoadjuvant chemo-radiotherapy was given to the patients according to the onco-surgical guidelines. Results. The level of c-myc expression was continuously decreasing after surgery. The other oncogenes and the p53 tumor suppressor gene showed different patterns, but all the examined genes showed significantly lower expression 12 months after surgery. The CA19-9 level showed a decrease during the follow-up, while the CEA concentration was increasing, but both markers presented an elevated level at the 12(th) month of the study. The changes in the blood antioxidant capacity showed variable values, no correlation with other markers was observed. Conclusions. The expression of the studied genes was found to be in a good correlation with the efficacy of the surgery, enabling monitoring the status of CRC patients better than with traditional tumor markers. Eur. J. Oncol., 16 (2), 99-104, 2011