Novel small deletions of the p53 gene in late-stage B-cell chronic lymphocytic leukaemia

Summary . A group of 20 CLL patients selected for advanced clinical stage p53 mutations were analysed by single-strand conformational polymorphism (SSCP) following PCR amplification of exons 5–9. In two patients abnormal SSCP of either exon 5 or exon 8 was found and PCR products were analysed by direct sequencing. A hemizygous or homozygous 12bp deletion at codon 135 and 3bp heterozygous deletion at codon 264 were detected; also, in the latter sample a heterozygous mutation at codon 282 (Arg to Gln) was found. To our knowledge, this is the first report of p53 deletions in B-CLL. The two patients were elderly, and both had a rapidly progressive disease in the absence of unfavourable cytogenic abnormalities. These findings support a role for p53 alterations in the clinical course of some B-CLL patients.