Chromosomal deletion in patients with malignant pleural mesothelioma

Our plain-English summary of Chromosomal deletion in patients with malignant pleural mesothelioma, by S. Neragi-Miandoab, D.J. Sugarbaker (Interactive Cardiovascular and Thoracic Surgery, 2009).

The study

• Authors: S. Neragi-Miandoab, D.J. Sugarbaker
• Journal: Interactive Cardiovascular and Thoracic Surgery
• Published: 2009;9(1):42-4
• Cited by: 11 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Malignant pleural mesothelioma (MPM) is associated with frequent deletions of specific chromosomal regions within 1p, 3p, 6q, 9p, 13q, 15q, and 22q. In this retrospective review of our patients with MPM, the tumor tissue of 40 patients (31 male and 9 female) was evaluated for chromosomal deletions and was karyotyped. Chromosomal deletions in regions 1p, 3p, 6p, 9p, 6q, 9q, 22q were observed in 22 of 40 patients (55%). Of this group of 22 patients, 15 (68%) demonstrated deletions in chromosome 6; 12 (54%) exhibited deletions in chromosome 22q; and 13 (59%) had deletions in chromosome 9p. Asbestos exposure was found in only 13 of the 22 patients (59%) with chromosomal deletions. There was no correlation between asbestos exposure and chromosomal deletion (95% CI -0.38-0.23, P=0.63). Chromosomal deletion did not correlate with age (95% CI -0.45-0.14, P=0.29). The majority of patients with chromosomal deletions had epithelial histology (17 of 22 patients; 77%), which was not statistically significant (95% CI -0.14-0.46, P=0.27). Chromosomal deletion is common in tumor tissue of MPM and the inactivation of tumor suppressor genes (TSGs) residing in these chromosomes may contribute to mesothelial cell tumorigenesis.

In plain English

This was a retrospective review of chromosome analyses (karyotypes) of tumor tissue from patients with malignant pleural mesothelioma. It looked for chromosomal deletions and any link with environmental factors. Of 60 patients first included, 20 were dropped because their samples had too few viable cells. That left 40 patients (31 men, 9 women; average age 61). Deletions were found in 22 of the 40 (55%). Among those 22, 15 (68%) had deletions on chromosome 6q, 14 (64%) on 3p, 13 (59%) on 9p and 12 (54%) on 22q. Only 13 of the 22 patients with deletions had a known history of asbestos exposure, and 12 asbestos-exposed patients had no deletion. The authors found no statistically significant correlation between asbestos exposure and deletion (P = 0.63), and deletion did not correlate with age. The authors concluded that deletion is common in this tumor and that loss of tumor suppressor genes on the deleted chromosomes may contribute to it. They noted the small, retrospective sample. Normal tissue was not tested, so they could not tell whether the deletions came before the cancer.

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: Retrospective review of tumor-tissue karyotypes (chromosome analysis) at a single institution
• Who was studied: Patients with malignant pleural mesothelioma. Sixty were initially included. Twenty were excluded because their specimens had insufficient viable cells, leaving 40 (31 males, 9 females). Their average age was 61 plus or minus 11 years (range 39 to 79), and the right-to-left pleura ratio was 22:18. Karyotyping was done at Brigham and Women's Hospital. The study dates are not given.
• Exposure: A known history of asbestos exposure, recorded per patient. No fiber types, products or doses are given. Some patients had radiation exposure, and one had SV40 exposure.
• Main results:
  • Of the 40 patients with informative karyotypes, 22 (55%) had chromosomal deletions.
  • Among the 22 patients with deletions: 12 (54%) had deletions in 22q, 13 (59%) in 9p, and 14 (64%) in 3p.
  • Among the 22 patients with deletions, 15 (68%) had a deletion on chromosome 6q.
  • Of the 22 patients with deletions, 13 (59%) had a known history of asbestos exposure. Twelve patients had asbestos exposure without evidence of deletion.
  • There was no statistically significant correlation between asbestos exposure and chromosomal deletion (95% CI -0.3802 to 0.2395, P = 0.63).
  • Nine patients had deletions without known asbestos exposure. Three of them had radiation exposure and one had SV40 exposure. Three of four patients with previous radiation therapy had deletions.
  • According to the article's abstract, chromosomal deletion did not correlate with age (95% CI -0.45 to 0.14, P = 0.29).
  • According to the article's abstract, 17 of the 22 patients with deletions (77%) had epithelial histology. This was not statistically significant (95% CI -0.14 to 0.46, P = 0.27).
• The authors' conclusion: The authors concluded that chromosomal deletion is common in tumor tissue of malignant pleural mesothelioma. They wrote that their data suggest loss of tumor suppressor genes on the deleted chromosomes is critical in, or may contribute to, mesothelial cell tumor development.
• Limitations the authors state:
  • Small sample size and retrospective design.
  • Patients' normal tissue was not evaluated. The study therefore cannot show whether the deletions resulted from the cancer or whether patients already had chromosomal instability before developing mesothelioma.

Topics

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

Medical terms in this study, explained in our Lexicon: Pleural Mesothelioma, Asbestos Exposure, Histology, Tumor Suppressor Gene, Mesothelial Cells, Tumorigenesis.

Related studies

• Deletions at 14q in malignant mesothelioma detected by microsatellite marker analysis — A.M. Björkqvist, M. Wolf, et al. (1999)
• A cluster of familial malignant mesothelioma with del(9p) as the sole chromosomal anomaly — M. Musti, D. Cavone, et al. (2002)
• Frequent deletion of 3p21.1 region carrying semaphorin 3G and aberrant expression of the genes participating in semaphorin signaling in the epithelioid type of malignant mesothelioma cells — Y. Yoshikawa, A. Sato, et al. (2011)
• Asbestos, chromosomal deletions, and tumor suppressor gene alterations in human malignant mesothelioma — S.S. Murthy, J.R. Testa (1999)
• Recurring loss involving chromosomes 1, 3, and 22 in malignant mesothelioma: possible sites of tumor suppressor genes — W.L. Flejter, F.P. Li, et al. (1989)
• del(6q) as a possible primary change in malignant mesothelioma — A.M. Meloni, C.F. Stephenson, et al. (1992)

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