DPEP1 and SDCBP2 mRNA expression is differentially regulated in CRC compared with normal colonic mucosa. (A) The mRNA expression of downregulated and upregulated genes in CRC samples was compared between microarray (white bars), SAGE (grey bars) and real-time PCR (qPCR, black bars) analyses. For real-time expression profiling, the RNA of 10 pairs of tumour and control samples (Discovery cohort) was isolated, reverse transcribed and the expression levels of SDCBP2, RHOC, NMES1, TM4SF1, TSPAN1, IFI27, OLFM4, LITAF, TBRG4 and DPEP1 were determined. The mRNA expression levels of each candidate gene were normalised to GAPDH and to the expression level observed in non-cancerous tissue. Data represent the mean mRNA expression plotted as the fold-change compared with control tissue (dotted line). *, no transcription tags were observed in non-cancerous control tissue in the SAGE analysis. Tu, tumour tissue; No, normal non-cancerous tissue. (B) The biomarker score was determined in the discovery cohort for all potential biomarker candidates (discovery cohort; black line) and in a set of 47 or 40 patients, respectively, for DPEP1 and SDCBP2 (validation cohort 1; grey line). Data represent the HR±95% CI. The corresponding P-values of LR tests are indicated.