Chromosome abnormalities in leukaemia and lymphoma.

Using improved techniques, chromosome abnormalities have now been identified in the majority of haematological disorders. Structural abnormalities have proved specific for morphological varieties of both leukaemia and lymphoma, in some cases specific for cell type, as in acute promyelocytic leukaemia, in others specific for cytogenetic varieties within a morphological group, as in the t(8;21) variety of acute myeloid leukaemia (M2). The 9;22 translocation found in most cases of chronic granulocytic leukaemia has been well recognised as a diagnostic feature for many years, and evolution of this disease to its acute leukaemic phase is accompanied by additional abnormalities. Chromosome changes in acute lymphocytic leukaemia are considered to be the most important independent prognostic indicator in this disease and more recently, changes which may have therapeutic implications have been found in almost all patients with Non Hodgkin's Lymphoma. Chromosome studies should be performed on the involved cells in all patients presenting with leukaemia and lymphoma for diagnosis and prognosis, and to establish a base line for remission and evolution of the disease. Such studies are also yielding valuable information regarding the derivation and aetiology of these disorders.