Chromosomal abnormalities and their correlations with asbestos exposure and survival in patients with mesothelioma

Our plain-English summary of Chromosomal abnormalities and their correlations with asbestos exposure and survival in patients with mesothelioma, by M. Tiainen, L. Tammilehto, J. Rautonen, et al (British Journal of Cancer, 1989).

The study

• Authors: M. Tiainen, L. Tammilehto, J. Rautonen, T. Tuomi, K. Mattson, S. Knuutila
• Journal: British Journal of Cancer
• Published: 1989;60(4):618-26
• Cited by: 79 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text
• In J-M's library: Johns-Manville's company medical library held a copy (J-M no. 000170).

Abstract

Cytogenetic findings of our 30 previously reported and eight new patients with malignant pleural mesothelioma were summarised and correlated with asbestos fibre burden in lung tissue and survival. Successful cytogenetic analyses were performed on cells obtained from the tumours and/or pleural effusions of 34 of the 38 patients. Clonal chromosomal abnormalities were detected in 25 patients, 19 of them studied before treatment. Nine patients, seven of them studied before treatment, had normal karyotypes and/or non-clonal chromosomal abnormalities. Most of the karyotypic findings in the patients with clonal abnormalities were complex and heterogeneous, and no chromosome aberration specific to mesothelioma could be demonstrated. The following numerical abnormalities in decreasing order of frequency were preferentially present in karyotypic changes: -22, +7, -1, -3, -9, +11 and -14 (-/+ denoting partial or total loss or gain). Translocations and deletions involving a breakpoint at 1p11-p22 were the most frequent structural aberrations. Statistically significant correlations were found between high content of asbestos fibres in lung tissue and partial or total losses of chromosomes 1 and 4, and a breakpoint at 1p11-p22 (P = 0.0001, P = 0.003, P = 0.009, respectively). The number of copies of chromosome 7 short arms was inversely correlated with survival (P = 0.02). In this study no diagnostic cytogenetic markers of mesothelioma were found, instead the copy number of chromosome 7 short arms turned out to be a possible prognostic factor in malignant mesothelioma.

In plain English

This Finnish study examined chromosomes in tumour and pleural fluid samples from 38 patients with malignant pleural mesothelioma diagnosed in the Helsinki University Central Hospital area between 1984 and 1987. Thirty had been described in the authors' earlier report. Chromosome analysis succeeded for 34 patients. Of these, 25 had clonal (repeated) chromosome abnormalities, which were mostly complex. No abnormality specific to mesothelioma was found. The most frequent change was partial or total loss of chromosome 22, in 14 of 25 patients (56%). Partial or total gain of chromosome 7 was found in 13 patients (52%). Lung asbestos fibres were counted in 16 patients, and the main types were crocidolite, amosite and anthophyllite. Partial or total losses of chromosomes 1 and 4, and rearrangements involving a break in the region 1p11 to p22, were statistically associated with more than 5 million fibres per gram of dried lung tissue (P = 0.0001, 0.003 and 0.009). More copies of the short arm of chromosome 7 were associated with shorter survival (P = 0.02). The authors concluded that further studies are needed to confirm whether this is a prognostic factor.

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 chromosome (cytogenetic) analysis of a series of patients' tumour and pleural effusion samples. The findings were compared with lung asbestos fibre counts and with survival. The series combines 30 previously reported patients and 8 new ones.
• Who was studied: 38 patients with malignant pleural mesothelioma diagnosed in the catchment area of Helsinki University Central Hospital, Finland, between 1984 and 1987. Thirty were male, and the median age at diagnosis was 59 (range 39-83). Seventy-five specimens were studied.
• Exposure: Asbestos fibre content of dried lung tissue was measured in 16 patients. Eleven had more than 5 million fibres per gram (range 5.5-370 million), with exposure in shipyards, construction and maintenance work. Five had less than 5 million (range 0.1-3.1 million), with exposure in construction, electrical installation, power plant and transport trades. The main fibre types in both groups were crocidolite, amosite and anthophyllite.
• Main results:
  • No chromosomal abnormality specific to mesothelioma was found.
  • Partial or total loss of chromosome 22 was the most frequent loss, found in 14 of the 25 patients with clonal abnormalities (56%).
  • Partial or total gain of chromosome 7 was the most frequent gain, found in 13 of the 25 patients with clonal abnormalities (52%).
  • Partial or total losses of chromosomes 1 and 4, and chromosomal rearrangements involving a breakpoint at 1p11 to p22, were consistently accompanied by fibre concentrations above 5 million fibres per gram of dried lung tissue (P = 0.0001, P = 0.003 and P = 0.009 respectively).
  • The number of copies of the chromosome 7 short arm in tumour cells correlated inversely with survival (P = 0.02). Patients with a lost or normal number of copies survived longer than those with 1-4 extra copies.
• The authors' conclusion: The authors concluded that their analysis found no diagnostic marker of mesothelioma, but showed correlations between chromosome abnormalities, asbestos exposure and survival. They said further studies are needed to confirm whether the copy number of chromosome 7 short arms is a prognostic factor.
• Limitations the authors state:
  • Many unidentified marker chromosomes made it difficult to interpret true chromosomal losses.
  • The tumours were studied at an advanced stage, so the primary chromosome changes may have been masked by secondary changes from tumour progression or ageing.
  • Complex clones may have been present but missed by the analysis in patients with simple, normal or non-clonal findings.

Topics

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

Medical terms in this study, explained in our Lexicon: Asbestos Exposure, Mesothelioma, Pleural Mesothelioma, Pleural Effusion, Translocation, Malignant Mesothelioma.

Related studies

• Malignant mesothelioma: clinical characteristics, asbestos mineralogy and chromosomal abnormalities of 41 patients — L. Tammilehto, T. Tuomi, et al. (1992)
• Abnormalities of chromosomes 7 and 22 in human malignant pleural mesothelioma: correlation between Southern blot and cytogenetic analyses — M. Tiainen, J. Kere, et al. (1992)
• Chromosomes and chromosomal evolution in human mesotheliomas as reflected in sequential analyses of two cases — G. Stenman, K. Olofsson, et al. (1986)
• Asbestos, chromosomal deletions, and tumor suppressor gene alterations in human malignant mesothelioma — S.S. Murthy, J.R. Testa (1999)
• Specificity of asbestos-induced chromosomal aberrations in short-term cultured human mesothelial cells — K. Olofsson, J. Mark (1989)
• Interphase cytogenetics on paraffin sections of malignant pleural mesothelioma. A comparison to conventional karyotyping and flow cytometric studies — M. Tiainen, A. Hopman, et al. (1992)

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