In Situ localization of transforming growth factor beta and S-phase cells in patients with acute myeloid leukemia and myelodysplastic syndrome

: In situ localization of transforming growth factor beta (TGF-B) was accomplished in 16 acute myeloid leukemia (AML) and 11 myelodysplastic syndrome (MDS) cases. A modified and greatly shortened procedure for immunohistochemical localization of TGF-B using a monoclonal antibody was undertaken in plastic embedded bone marrow biopsy sections that demonstrated excellent preservation of morphologic detail. In addition, a double-label procedure was developed for the simultaneous detection of TGF-B and cells actively engaged in DNA-synthesis which were labeled in vivo by infusing thymidine analogues. Marked variation in intensity of TGF-B staining in interstitial areas of biopsies was noted among different patients. TGF-B was also conspicuously present in the basement membrane of blood vessel endothelial cells and the cytoplasm of megakaryocytes. Double-labeling revealed that S-phase cells in a number of MDS cases appeared clustered together and that megakaryocytes in S-phase were completely devoid of TGF-B.