Biomarker panel discovery for early detection of colorectal cancer in blood samples

Colorectal cancer (CRC) remains a highly curable disease if detected early and presently it is the third highest cause of cancer related death worldwide. The only non-invasive screening test for CRC is the fecal occult blood test (FOBT) and even though screening with FOBT leads to reductions in CRC incidence and mortality, there are difficulties using this assay as a diagnostic screening tool. Specifically, there is a low participation rate (44 – 47 %) and a low positive predictive value of 5.3 % for suspected cancers.
<a target=“_blank” href=http://www.ncbi.nlm.nih.gov/pubmed/20157748>Parro-Blanco et al 2010, also report that a highly sensitive immuno FOBT with sensitivity of 61% at 95% specificity has a low positive predictive value of 11 % for colorectal cancer as determined by follow-up colonoscopy. Currently, the FOBT false positives lead to many unnecessary colonoscopies.
We have identified a sensitive panel of protein CRC biomarkers in blood capable of detecting early CRC disease. New analyses of gene and protein expression profiling data, together with literature searches have enabled us to identify 55 potential CRC biomarkers. Serum and plasma were collected from 96 CRC patients (Dukes stages A-D) and 50 healthy age and gender matched volunteers. Candidate biomarker levels were analysed via ELISA or the Luminex multiplex system.

No single biomarker alone had adequate performance for diagnostic purposes. However, using logistic regression and a forward selection algorithm we identified a panel of seven proteins with a predictive sensitivity of 81% and specificity of 90% which is potentially useful for the diagnosis of CRC.

No relevant conflicts of interest declared.