Activin A as a novel biomarker for colorectal adenocarcinoma in humans.

OBJECTIVE Early diagnostics of colorectal cancer is complicated by the lack of reliable serum biomarkers. This study aimed to investigate if the serum level of activin A can be used for diagnostics of this disease. PATIENTS AND METHODS In this study we measured the level of activin A in patients with colorectal adenocarcinoma, benign colorectal polyps, as well as in healthy subjects. RESULTS We found that the level of activin A was significantly higher in patients with colorectal adenocarcinoma, as compared to patients with polyps and healthy controls. Furthermore, activin A levels correlated well with the stage of colorectal cancer. The level of activin A was substantially reduced in post-operative patients. Immunohistochemical staining demonstrated that high levels of activin A were present in the adenocarcinoma tissue samples but not in the non-cancerous samples. RT-PCR further confirmed that mRNA of ßA subunit of activin A is significantly over-expressed in the majority of cancerous samples. Western blotting results further demonstrated the elevated level of activin A in cancer samples. CONCLUSIONS Taken together, the findings suggest that colorectal adenocarcinomas directly secret activin A into the blood stream. Measuring the serum level of activin A might be used as a reliable diagnostic and screening tool in clinical practice.