Figure 8
From: Proteomic profiling of urine for the detection of colon cancer
Spiking of stable isotope labelled fibrinogen peptide into urine samples. Panel A shows the MALDI spectra of a urine sample spiked with 0.5 μg/ml heavy peptide and 0, 0.3, 0.7 and 1 μg/ml light peptide. Panel B plots the 'measured' concentration of light peptide against the actual concentration added (3 experiments in different urine samples devoid of the endogenous peptide). Panel C plots MALDI peak height at m/z 1885 for each sample in the study against 'measured' concentration (from the light/heavy peptide peak intensity) with non-cancer controls indicated by solid triangles and cancer patients by open squares.