Acute lymphoid leukemia (ALL) is the commonest type of cancer in childhood, representing 70% of cases. In adults its incidence is 20% only. The initial diagnosis approach consists of a peripheral blood and bone marrow cytomorphological examination. The rate of correctly classified cases is increased up to 99% through immunophenotypic study, which allows to identify the cell line (T or B) and the different stages of cell maturation. Nearly 20% derive from T cells, 75% from B-cell precursors and 5% from mature B-cells. The cytogenetic techniques have markedly contributed to the better understanding of molecular biology and ALL treatment. Chromosomal abnormalities, associated with the immunophenotyping panel, are the most important parameter for leukemia classification. Together with clinical and in vitro factors, this parameter allows the patients stratification in different risk groups, which is of great importance for establishing a prognosis and a suitable treatment. The aim of this study was to perform a bibliographic review of the laboratory methods by morphological, cytochemical, immune, cytogenetic and molecular genetic patterns, which are useful tools for acute lymphoid leukemia classification and diagnosis.
Acute lymphoid leukemia; Chromosome; Translocation; Immunophenotyping; Prognosis; Diagnosis