ABSTRACT
Leukemia comprises a heterogeneous group of hematological neoplasias characterized by clonal proliferation of hematopoietic cell lineages that underwent genetic alterations, leading to be expressed in a specific differentiation phase. The main clinical symptoms result in accumulation of immature precursors in the bone marrow (BM). Leukemia are a very heterogeneous and vast group of diseases, covering a wide range of ages. The possibility to undertake cytogenetic analysis of malignant cells represented the beginning of one of the greatest advances in understanding the biological nature of neoplasms. Refinements of chromosome banding techniques over the last 40 years allowed for improved detection of chromosomal abnormalities in malignant hemopathies. In situ hybridization is a cytogenetic method used for high-resolution detection and localization of DNA sequences in tissues and cells. The application of new multicolor karyotyping approaches allowed the complete characterization of complex chromosome rearrangements and the discovery of new abnormalities and putative genes involved in leukemic transformation.
