Human milk fat globule antigen 1 (HMFG1) expression in prostatic carcinomaand immunotargeting with a radiolabelled monoclonal anti-HMFG1 antibody

Background Prostatic cancer is the leading cause of death in Swedish men. A pproximately 50% have disseminated disease at diagnosis. Radiolabelled anti bodies could possibly be a treatment modality for dissenminated prostatic c ancer, so that in this study the expression of the human milk fat globulin I (HMFGI) antigen in prostate cancer was examined Materials and Methods: An immunohistochemistry technique with a murine monoclonal antibody was used, as well as the human prostate cancer cell line DU-145, which expresses thi s cell surface antigen. TUR specimens from patients with prostate cancer we re also examined. Results: Eighteen out of 22 (82%) patients exhibited an H MFG1- positive tumour. An inhomogenity in the immunostaining could occasion ally be seen, with smaller apparently negative areas. The immunolocalisatio n properties of the antibody were investigated using a radiolabelled antibo dy injection into nude mice bearing heterotransplants of the DU-145 cell li ne. The highest accumulation of the antibody was seen in the tumour tissue and the liver. Conclusion. The results obtained form a basis for further in vestigations with the goal of using the antibodies for staging and therapy for prostate cancer.