Fragments of PKM (PKM fr) were identified from spot 5603, from spot 4405 together with PRDX4 and ATP5F1B fr and from spot 4608 together with TCP1. Spot 4405 showed higher expression in the peripheral and central part of the tumor compared to the non-involved part, whereas spot 5603 only was identified as differentially expressed in the central tumor tissue compared with the non-involved colorectal tissue. Here, PRDX4 is linked to neoplasm.