Study of epigenetic changes as potential biomarkers in noninvasive diagnosis of colorectal cancer

Abstract

Colorectal cancer (CRC) is the second most common cancer in Europe and the U.S. (Tanzer et al., 2010). The number of new cases of cancer of the colon and rectum in estimating for Brazil in 2010 published by INCA is 13,310 cases in men and 14,800 women (INCA, 2010). Despite undeniable improvements in medical practices and surgical mortality rate for colorectal cancer the overall survival after five years remains at around 40% (Ferreira et al., 2004). The CRC results from the accumulation of multiple somatic mutations in a cell (Ferreira et al., 2004). Evidence has shown that both genetic and epigenetic changes have equal importance in the pathogenesis of CRC. In particular, tumor suppressor genes can be silenced by methylation of CpG islands that are found in the 5 'region in approximately half of the genes in humans (Gonzalo et al., 2010). The CRC can be cured in up to 90% of cases when detected in early stage. There is growing expectation that new generation of screening tests based on detection of blood markers should improve patient compliance screening of the CRC as evidenced by the success of screening programs such as for hipercholesterolemia or prosatae cancer. Determination of epigenetic events is a strong candidate for early detection of disease, since the regulation of gene expression by aberrant DNA methylation is a well characterized event in tumor biology and widely described for CRC (Gonzalo et al., 2010). The purpose of this research is to study the sensitivity and specificity of the method in the diagnosis of colorectal cancer and the detection of neoplastic lesions based on epigenetic markers, since invasive methods are not accessible due to its high cost and various other factors. (AU)