Mutation of p53 in primary biopsy material and cell lines from Hodgkin disease.
The p53 tumor-suppressor gene encodes a nuclear phosphoprotein that arrests cell cycle progress at G1. It may facilitate DNA damage repair and is frequently mutated in many human tumors. Hodgkin disease, a malignant condition of the lymphoid system, is characterized by the presence of Reed-Sternberg cells and mononuclear variants (Hodgkin cells), whose etiology remains unknown. The large multinucleated Reed-Sternberg cells often comprise < 1% of the total cell population within a biopsy specimen and are thought to be the neoplastic component in an admixture of reactive cells. It has been shown in the large majority of cases that up to 60% of these multinucleated cells react with CM-1, an anti-p53 antibody. However, whether this "overexpression" of p53 protein reflects abnormality at the DNA level can no longer be assumed by immunocytochemistry alone. p53 from six Hodgkin disease-derived cell lines was examined by immunoprecipitation, polymerase chain reaction (PCR)-single-strand conformation polymorphism analysis, and sequencing. In one cell line, point mutations were identified in exons 5 and 8 of p53. Sequencing of cloned PCR products confirmed the mutations to be on different alleles. A strategy involving extraction of nuclei followed by enrichment by flow cytometry was used to determine whether p53 overexpression in the Reed-Sternberg cells from patient biopsy material was due to mutations in this gene. Single-strand conformation polymorphism revealed additional bands in the polyploid nuclear preparations, suggesting abnormalities, and sequence analysis confirmed the presence of point mutations.
Gupta
R K
RK
Imperial Cancer Research Fund, Department of Medical Oncology, St. Bartholomew's Hospital, London, United Kingdom.
Patel
K
K
Bodmer
W F
WF
Bodmer
J G
JG
D001483:Base Sequence; D001706:Biopsy; D015153:Blotting, Western; D002467:Cell Nucleus / Q000648:ultrastructure; D003062:Codon / Q000235:genetics; D004249:DNA Damage; D004273:DNA, Neoplasm / Q000032:analysis / Q000235:genetics; D016158:Genes, p53; D006689:Hodgkin Disease / Q000235:genetics* / Q000473:pathology; D006801:Humans; D017403:In Situ Hybridization; D008938:Mitosis; D008969:Molecular Sequence Data; D009154:Mutation; D016133:Polymerase Chain Reaction / Q000379:methods; D016539:Reed-Sternberg Cells / Q000473:pathology; D014407:Tumor Cells, Cultured
D003062:Codon; D004273:DNA, Neoplasm