NOVEL SMALL DELETIONS OF THE P53 GENE IN LATE-STAGE B-CELL CHRONIC LYMPHOCYTIC-LEUKEMIA

A group of 20 CLL patients selected for advanced clinical stage p53 mu tations were analysed by single-strand conformational polymorphism (SS CP) 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 analy sed by direct sequencing. A hemizygous or homozygous 12bp deletion at codon 135 and 3bp heterozygous deletion at codon 264 were detected; al so, in the latter sample a heterozygous mutation at codon 282 (Arg to Gin) was found. To our knowledge, this is the first report of p53 dele tions in B-CLL. The two patients were elderly, and both had a rapidly progressive disease in the absence of unfavourable cytogenic abnormali ties. These findings support a role for p53 alterations in the clinica l course of some B-CLL patients.