We found three truncated p53 transcripts in a patient with chronic myelogenous leukaemia in blast crisis carrying chromosome 17 abnormalities. Sequencing of these transcripts revealed complete absence of the entire exons 7, 8 and 9 in one, exons 8 and 9 in another, and exon 10 in the other. Sequencing analysis of genomic DNA, however, revealed no mutation in exons 6-10 and their flanking introns. These results suggest that the aberrant p53 transcripts in this case might not result from splicing mutations but from an unknown affected splicing process.