Patients and method: The expression of TGF-beta-3 was examined in 64 patients with reactive and malignant effusion by immunocytochemistry.
Result: In about half of the patients with malignant effusions (especially breast cancer, gastric cancer, and carcinomas of unknown primary) TGF-beta positive tumor cells could be detected. We could show here for the first time that reactive mesothelial cells could also express TGF-beta. Lymphatic cells were negative in all cases. TGF-beta-3 bioactivity could also be detected in the effusions studied. In our group of patients with far advanced cancer, the expression of TGF-beta had no clear-cut clinical or prognostic correlate. However, the expression of TGF-beta on tumor cells should be interpreted as a marker of tumor progression, taking into account the fibrogenic, angiogenic and immunosuppressive properties of TGF-beta.
Conclusion: Further research is necessary to answer the question if the 3 isoforms of TGF-beta are coordinately expressed and to elucidate the involvement of this cytokine in tumor progression and metastasis.