Figure 2. Detection of antibody-reactive proteins in tissue extracts from a female patient with stage IV colon cancer and liver metastasis.

Proteins extracted from tissue of normal colon (A: CN2) and colon adenocarcinoma (B: CA2), and liver metastases (C: LM2) were analyzed by 2D electrophoresis. Protein extracts were blotted with a control serum containing high-titer autoantibodies from an autoimmune disease patient to exclude autoantigens non-specific to the cancer patient (D-F). Cancer-specific proteins that induced serum antibodies were revealed by blotting with serum from the cancer patient (G-I). Note that cancer-specific immunogen-antibody reactivity patterns in colon tumor (H) and liver metastatic tissue (I) appear similar.