Therapy-related myelodysplastic syndromes: FAB classification, bone marrow histology, and immunohistology in the prognostic assessment. 
In this study we describe the morphologic and immunohistochemical evaluation of bone marrow biopsies from 14 patients with therapy-related myelodysplastic syndromes (t-MDS).  We employed CD34, anti-HLA-Dr, anti-elastase, CD68, anti-glycophorin, CD61 monoclonal antibodies immunostaining, and enzyme histochemistry for chloroacetate esterase.  Moreover, we used PC10, a MAb raised against the proliferating cell nuclear antigen, to study the proliferative capacity of these marrows.  Our data suggest that diagnosis of refractory anemia with excess of blasts (versus chronic myelomonocytic leukemia), the abnormal localization of immature precursors, marrow fibrosis, and augmented CD34 expression in the bone marrow biopsy are ominous prognostic factors at a statistically significant level (p < 0.0005).  A combined morpho-immunohistochemical analysis of bone marrow biopsy correctly classifies t-MDS cases according to the biologic and clinical aggressiveness.