Absence of p53 mutations in malignant mesotheliomas

Our plain-English summary of Absence of p53 mutations in malignant mesotheliomas, by O. Mor, P. Yaron, M. Huszar, et al (American Journal of Respiratory Cell and Molecular Biology, 1997).

The study

• Authors: O. Mor, P. Yaron, M. Huszar, A. Yellin, O. Jakobovitz, F. Brok-Simoni, G. Rechavi, N. Reichert
• Journal: American Journal of Respiratory Cell and Molecular Biology
• Published: 1997;16(1):9-13
• Cited by: 74 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Mutations in the p53 gene are the most common genetic alterations found in human malignancies. In this study, a search was done for mutations in the conserved regions of the p53 gene in malignant mesotheliomas. Thirteen malignant mesotheliomas collected over the preceding 12 yr and maintained in paraffin blocks were examined by polymerase chain reaction (PCR) followed by both single-strand conformation polymorphism (SSCP) and denaturing gradient-gel electrophoresis (DGGE). Direct sequence analysis was performed in cases suspected for mutations. No mutations in exons 5 to 8 of the p53 gene were detected. Our results suggest that malignant transformation of human mesothelioma cells does not require inactivation of p53 by point mutations in the conserved regions of the gene.

In plain English

This laboratory study at the Chaim Sheba Medical Center in Israel looked for mutations in the p53 gene in malignant mesothelioma tumors. The p53 gene is a tumor-suppressor gene that is often altered in human cancers. The authors examined stored tissue from 13 malignant mesotheliomas collected beginning in 1982. All but one tumor arose in the pleura; the remaining one was a peritoneal mesothelioma. The patients were males and females aged 31 to 77. Asbestos exposure was documented in two patients. Other listed risk factors were heavy smoking (four patients), irradiation (one patient) and multiple malignancies (three patients). Using two laboratory screening methods, the authors examined exons 5 to 8, the conserved regions of the gene. No mutations were detected. One tumor showed an abnormal result in exon 7, but sequencing did not confirm a change, and the authors attributed it to an error in the first laboratory amplification step. The authors concluded that such mutations are not a prominent feature of primary malignant mesotheliomas. Because asbestos exposure was documented in only 2 of 13 cases, they stated that their results cannot entirely exclude effects of asbestos on the p53 gene.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Laboratory molecular genetic analysis of archived tumor tissue (series of 13 tumors), screening p53 exons 5 to 8 with SSCP and DGGE, followed by direct sequencing of suspect samples
• Who was studied: 13 malignant mesotheliomas stored as paraffin-embedded blocks at the Chaim Sheba Medical Center, Israel, collected beginning in 1982. Patients were males and females aged 31 to 77. All tumors were pleural except one peritoneal mesothelioma. Twelve patients died 1 to 30 months after diagnosis.
• Exposure: Asbestos exposure was documented in two patients; no fiber types are given. Other risk factors listed were heavy smoking (four patients), irradiation (one patient) and multiple malignancies (three patients).
• Main results:
  • No mutations were detected in the conserved region of the p53 gene (exons 5 to 8) in the 13 malignant mesotheliomas.
  • One tumor showed an altered pattern in exon 7 on both screening methods, but sequencing of both DNA strands did not confirm a base-pair change.
  • Repeat testing of that tumor suggested no exon 7 mutation, and the authors attributed the initial result to errors in the first Taq polymerase amplification, calling it a false positive.
• The authors' conclusion: The authors concluded that mutations within the conserved regions of p53 are not a prominent feature of primary malignant mesotheliomas, and that malignant transformation of mesothelioma cells does not require inactivation of p53 by point mutations in these regions.
• Limitations the authors state:
  • Asbestos exposure was documented in only 2 of the 13 cases, so the authors stated that the results cannot entirely exclude possible effects of asbestos on the p53 gene.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Mesothelioma.

Medical terms in this study, explained in our Lexicon: Malignant Mesothelioma, Paraffin Block, Malignant Transformation, Mesothelioma.

Related studies

• P53 mutations in tumours induced by intraperitoneal injection of crocidolite asbestos and benzo[a]pyrene in rats — K. Unfried, N. Kociok, et al. (1997)
• Mutations of p53 gene and SV40 sequences in asbestos associated and non-asbestos-associated mesotheliomas — F.G. Mayall, G. Jacobson, et al. (1999)
• Analysis of K-ras and p53 mutations in mesotheliomas from humans and rats exposed to asbestos — Z. Ni, Y. Liu, et al. (2000)
• p53 and ras gene mutations in lung cancer: implications for smoking and occupational exposures — K. Husgafvel-Pursiainen, M. Ridanpää, et al. (1995)
• Lung cancer and past occupational exposure to asbestos. Role of p53 and K-ras mutations — K. Husgafvel-Pursiainen, A. Karjalainen, et al. (1999)
• Survival in operable non-small-cell lung cancer: role of p53 mutations, tobacco smoking and asbestos exposure — T. Sioris, K. Husgafvel-Pursiainen, et al. (2000)

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