Mutations of the p53 gene as a prognostic factor in aggressive B-cell lymphoma.
ABSTRACT Mutations of the p53 gene are associated with a poor prognosis in several types of cancer. We investigated the prognostic importance of p53 mutations in patients with aggressive B-cell lymphoma.
We examined the relation between the presence or absence of a detectable p53 mutation in lymphoma cells and the response to chemotherapy and overall survival in 102 previously untreated patients with aggressive B-cell lymphoma. Mutations of the p53 gene were identified by polymerase-chain-reaction-mediated analysis of single-strand conformation polymorphisms and by direct sequencing.
Of 102 cases of aggressive B-cell lymphoma, 22 (22 percent) involved p53 mutations. The rate of complete remission was significantly lower in patients with a tumor carrying a p53 mutation (6 of 22 patients, 27 percent) than in those with the wild-type p53 gene (61 of 80 patients, 76 percent) (P<0.001). Overall survival was significantly lower among patients with p53 mutations than among those with the wild-type p53 gene; the Kaplan-Meier estimates of survival at five years were 16 percent and 64 percent, respectively (P<0.001). Multivariate analysis incorporating prognostic factors from the international prognostic index demonstrated that p53 mutations had independent effects on the rates of complete remission and survival. When we categorized patients according to the international prognostic index, we found no effect of p53 mutations in patients in the groups at high-intermediate and high risk. However, these mutations were significantly associated (P< 0.001) with low rates of complete remission (33 percent vs. 91 percent) and survival (27 percent vs. 81 percent at five years) in the groups at low and low-intermediate risk.
Mutations of the p53 gene are associated with a poor prognosis in patients with aggressive B-cell lymphoma.
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ABSTRACT: Human T-cell leukemia and T-cell acute lymphoblastic leukemia cell lines were studied for alterations in the p53 tumor suppressor gene. Southern blot analysis of 10 leukemic T-cell lines revealed no gross genomic deletions or rearrangements. Reverse transcription-polymerase chain reaction analysis of p53 mRNA indicated that all 10 lines produced p53 mRNA of normal size. By direct sequencing of polymerase chain reaction-amplified cDNA, we detected 11 missense and nonsense point mutations in 5 of the 10 leukemic T-cell lines studied. The mutations are primarily located in the evolutionarily highly conserved regions of the p53 gene. One of the five cell lines in which a mutation was detected possesses a homozygous point mutation in both p53 alleles, while the other four cell lines harbor from two to four different point mutations. An allelic study of two of the lines (CEM, A3/Kawa) shows that the two missense mutations found in each line are located on separate alleles, thus both alleles of the p53 gene may have been functionally inactivated by two different point mutations. Since cultured leukemic T-cell lines represent a late, fully tumorigenic stage of leukemic T cells, mutation of both (or more) alleles of the p53 gene may reflect the selection of cells possessing an increasingly tumorigenic phenotype, whether the selection took place in vivo or in vitro. Previously, we have shown that the HSB-2 T-cell acute lymphoblastic leukemia cell line had lost both alleles of the retinoblastoma tumor suppressor gene. Taken together, our data show that at least 6 of 10 leukemic T-cell lines examined may have lost the normal function of a known tumor suppressor gene, suggesting that this class of genes serves a critical role in the generation of fully tumorigenic leukemic T cells.Molecular and Cellular Biology 11/1990; 10(10):5502-9. · 5.37 Impact Factor
Article: p53 function and dysfunction.Cell 09/1992; 70(4):523-6. · 31.96 Impact Factor
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ABSTRACT: The alteration of p53 tumor suppressor gene was studied in 48 patients with B-cell lymphoma. A sequential combined technique of polymerase chain reaction-mediated single-strand conformational polymorphism (PCR-SSCP) or reverse transcription (RT)-PCR-SSCP and direct sequencing were used as a simple and sensitive approach to analyze nucleotide changes. By these methods, we identified 8 missense point mutations and 2 codon deletions in 9 of the 48 patients. These mutations were located in or close to the evolutionally highly conserved regions of the p53 gene. Eight of nine patients having p53 gene alterations were in advanced clinical stage (IV). It is the first report of p53 gene mutations in follicular and diffuse lymphoma. These observations suggest that the p53 gene alteration may play an important role in lymphomagenesis and/or disease progression in some types of B-cell lymphoma.Blood 06/1992; 79(10):2701-7. · 9.06 Impact Factor