Studies of the geographic patterns of c-myc expression in bone marrow

C-myc expression was studied semi-quantitatively in bone marrow biopsies obtained from normal individuals, patients with non-malignant haematological disorders and patients with various haematological malignancies. In normal bone marrow and in the bone marrow of patients with non-malignant haematological disorders, cells containing c-myc protein are present in small clones (average 7 +/- 2.5 cells/clone) located in the centre of the histotopographic region of the biopsy. In contrast, c-myc-containing cells are diffusely distributed in the bone marrow of patients with acute myelogenous leukaemia (AML). In the marrow of patients with myelodysplastic syndromes evolving to AML and in patients with AML in early relapse, the clones of cells containing c-myc are larger than those present in normal marrows (average clone size = 17.5 +/- 3.5 cells). Additionally, the proportion of the cells in normal bone marrow which express c-myc protein is less than that present in AML marrows (23.3 +/- 10.17 v. 60.2 +/- 6.17) and the intensity of staining is also less. Non-Hodgkin's lymphoma patients with bone marrow involvement had distribution of c-myc positive cells similar to those with leukaemic infiltration.