DETECTION OF P53 GENE-MUTATIONS IN HUMAN LEUKEMIA BY PCR-SSCP ANALYSIS AND DIRECT NUCLEOTIDE SEQUENCING

Objective To look for mutations of the p53 gene in leukimic patients a nd study the relationship between abnormalities in p53 gene and leukem ogenesis. Methods The peripheral blood and Bone Marrow Samples were co llected from 36 patients with various leukemia types including 14 case s of lymphocytic leukemia [8 cases of acute lymphocytic leukemia (ALL) , 4 cases of chronic lymphocytic leukemia (CLL), 2 cases of hairy cell leukemia (HCL)] and 22 cases of myelocytic leukemia [11 cases of acut e non-lymphocytic leukemia (ANLL), 11 cases of chronic myelocytic leuk emia (CML)]. DNA structures of exon 5-8 of the p53 gene were scanned b y PCR-SSCP (single strand conformation polymorphism analysis of polyme rase chain reaction products). The appropriate DNA fragments were ampl ified, Purified and sequenced directly. Results By PCR-SSCP analysis, shifts in electrophoretic mobility of the p53 gene were detected in 3 of 14 patients with lymphocytic leukemia (2 ALL and 1 CLL), but none i n 22 patients with myelocytic leukemia including one in blastic crisis . Direct nucleotide sequencing in one patient with ALL showed transiti on of CTG to CAG at codon 257 of exon 7, resulting in a change of its encoded amino acids from aspartic acid to valine. To our knowledge, th e mutation at this codon has not been previously reported hitherto. Co nclusions The p53 gene mutations are specifically associated with lymp hocytic leukemia. Alternations of the p53 gene may play a certain role in leukemogenesis in some cases of lymphocytic leukemia.