The presence of free
nucleic acids in plasma has been detected in
cancer patients and is associated with poor prognosis. In the present study, the
mRNA levels of three genes (EPAS1, KIAA0101 and UBE2D3) in plasma from
colorectal cancer patients were analyzed. These genes were selected from a previous study of genomic profiles, discriminating between healthy controls and
colorectal cancer patients.
mRNA levels were analyzed by real-time PCR in the plasma of 154 patients with
colorectal cancer. The association of plasma
mRNA levels with clinicopathological parameters and patient survival were analyzed. High levels of EPAS1 in the plasma were associated with patients aged over 50 years, relapse of disease and patient mortality. When patients were divided into two groups, early (I and II) and advanced (III and IV) stages, an association was observed between high levels of EPAS1
mRNA and worse disease-free and overall survival in advanced stages. The expression of KIAA0101 and UBE2D3 was not associated with poor prognosis. Thus, our results suggest that EPAS1
mRNA levels may be an
indicator of poor prognosis in
colorectal cancer patients at advanced stages, obtained by a non-invasive method.