The invention relates to a method of diagnosis of colorectal cancer in a diagnostic sample of a valid body tissue taken from a human subject, which comprises detecting an increased concentration of a protein in the diagnostic sample, compared with a control, normal human sample, the protein being: transforming growth factor-beta induced protein IG-H3 (SwissProt Acc. No. Q15582); suppressor of G2 allele of SKP1 homolog (isoform 2) (SwissProt Acc. No. Q9Y2Z0-2); hypothetical protein (part of URG4) (SwissProt Acc. No. Q9NWR7); calponin-2 (SwissProt Acc. No. Q99439); heat shock protein HSP90-beta (SwissProt Acc. No. P08238); phosphoglycerate mutase 1 (SwissProt Acc. No. P18669); serpin C1 protein (SwissProt Acc. No. P01008); or haptoglobin precursor (SwissProt Acc. No. P00738); or a decreased concentration of a protein in the diagnostic sample, compared with a control, normal human sample, the protein being serotransferrin (SwissProt Acc. No. P02787); 26S proteasome subunit p40.5 (Swiss Prot Acc. No. Q9UNM7); aldo-keto reductase family 1 member B10 (SwissProt Acc. No. O60218); fructosamine-3-kinase (SwissProt Acc. No. Q9H479); peripherin (SwissProt Acc. No. P41219); alpha-2-macroglobulin (SwissProt Acc. No. P01023); serpin C1 protein (SwissProt Acc. No. P01008); or apolipoprotein A IV (SwissProt Acc. No. P06727). The same proteins can be used for prognosis by detecting changes in their concentration in the course of treatment for colorectal cancer.