[Alterations of the p53 gene and clinical features in childhood acute lymphoblastic leukemia]

Correlations between alterations of the p53 gene and clinical features were examined in childhood acute lymphoblastic leukemia (ALL). We analyzed 147 patients and 38 cell lines for p53 mutations within exons 5 to 9 (2 to 11 in some of them) by polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) analysis and direct sequencing. p53 gene mutations were found in 3 of 62 (5%) patients at diagnosis, 1 of 14 (7%) patients at relapse, and 13 of 20 (65%) cell lines in T-ALL, 2 of 20 (10%) patients at diagnosis, 4 of 4 (100%) patients at relapse, and 4 of 5 (80%) cell lines in t(1;19)-ALL, 1 of 23 (4%) patients at diagnosis, 2 of 22 (9%) patients at relapse, and 5 of 12 (42%) cell lines in common ALL other than t(1;19) or t(9;22)-ALL and 3 of 3 (100%) patients at diagnosis in B-ALL. In t(1;19)-ALL, p53 gene alterations were associated with a poor prognosis. The patients with p53 mutations had a trend towards poor prognosis in childhood ALL without B-ALL. p53 gene mutation is not always associated with the current prognostic factors. This alteration may become one of the important prognostic factors, if the detection of a small number of the leukemic cells with the p53 gene mutation would be possible.