Objective: To screen and identify the immunogenic membrane antigens in human pancreatic cancer for early diagnosis.
Methods: Membrane protein was extracted from pancreatic cancer cell lines and separated by using 2-DE. One of the two parallel 2-DE gels went for staining while the other underwent immunoblot. Serum IgG, which was purified from clinically collected sera of pancreatic cancer patients, was used as the primary antibodies for the immunoblot. Positive dots of immunoblot were identified by MALDI-TOF mass spectrometry and PMF matching, and then evaluated by bio-informatics methods. The candidate membrane antigens were further validated respectively in cell lines and tissues by RT-PCR and immunohistochemistry.
Results: The immunoblot of mixed membrane protein with serum IgG from cancer patients showed eight positive dots. These dots were identified with MALDI and PMF as: VDAC-1, VDAC-2, CHCHD3, SLP-2 and TOM40. RT-PCR showed that these membrane antigens were expressed in several pancreatic cancer cell lines. Immunohistochemistry showed prominent SLP-2 over expression in cancer tissue.
Conclusions: VDAC-1, VDAC-2, CHCHD3, SLP-2, and TOM40 are the new candidate immunogenic membrane antigens of pancreatic cancer. These membrane antigens can be subsequently tested in high dangerous population for early diagnosis of pancreatic cancer.