[Significance of cytogenetic studies in the preleukemias].

In cytogenetic examinations made on 60 patients in preleukemic states an instable karyotype could be identified in 28% of all cases and anomalous clones in 12.3%. The dynamics of transition to acute leukemia was pursued in seven cases. The instability of the karyotype is conceived of as a sign of increased risk to developing leukemia and the presence of anomalous clones as an evidence of a leukemic process.