Cytogenetic follow-up in chronic myeloid leukemia.

Twenty-six patients with Philadelphia chromosome (Ph1)-positive chronic myeloid leukaemia have been followed-up cytogenetically. Twelve patients were found to have chromosome abnormalities in addition to the Ph1, either in the chronic phase or during progression of disease. The most common abnormality observed was an additional chromosome No. 19 although trisomy 8, a second Ph1 and isochromosome 17 were also observed.