[Cytogenetics of preleukemic states].

In about a half of preleukemic states it is possible to find chromosomal aberrations, as three n. degrees 8 chromosomes, a single n. degrees 7 or n. degrees 5 chromosome, or a partial deletion of long arm or n. degrees 5 chromosomes. From a prognostic point of view, the presence of the indicated chromosomal abnormalities show a three times increased risk to suffer leukemia. Several abnormal cell clones may be produced, but generally only one of them has the proliferative capacity to establish an evolutive non-lymphoblastic acute leukemic process.