Immunohistochemical Expression of Aquaporin-1 in Fluoro-Edenite-Induced Malignant Mesothelioma: A Preliminary Report

Our plain-English summary of Immunohistochemical Expression of Aquaporin-1 in Fluoro-Edenite-Induced Malignant Mesothelioma: A Preliminary Report, by G. Angelico, R. Caltabiano, C. Loreto, et al (International Journal of Molecular Sciences, 2018).

The study

• Authors: G. Angelico, R. Caltabiano, C. Loreto, A. Ieni, G. Tuccari, C. Ledda, V. Rapisarda
• Journal: International Journal of Molecular Sciences
• Published: 2018;19(3)
• Cited by: 16 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Background: The immunohistochemical expression of aquaporin-1 (AQP1) in asbestos-related malignant pleural mesothelioma (MPM) is emerging as a useful prognostic indicator of improved survival. A significantly increased incidence of MPM in a small town in southern Italy was ascribed to exposure to fluoro-edenite (FE), a naturally occurring asbestos fiber. We investigated the immunohistochemical expression of AQP1 in patients affected by FE-related MPM; taking into consideration its suggested independent prognostic role, its possible correlation with clinicopathological parameters and patient outcome was also evaluated.

Methods: Ten patients were selected for this study, as neoplastic tissue blocks, clinical and follow-up data were available. The immunohistochemical overexpression of AQP1 was defined as ≥50% of tumor cells showing membranous staining.

Results: Six cases showed AQP1 expression in ≥50% of tumor cells; in this group, a significant association of AQP1 overexpression with an increased median overall survival (OS) of 26.3 months was observed. By contrast, four patients exhibited an AQP1 score of <50% of stained cells, with a shorter median OS of 8.9 months.

Conclusions: The present study represents further confirmation of the hypothesized prognostic role of AQP1, which seems a reliable prognostic indicator.

In plain English

This preliminary study examined tumor tissue from 10 people with malignant pleural mesothelioma who lived in or near Biancavilla, Sicily. The authors attribute the town's increased mesothelioma to environmental exposure to fluoro-edenite, an asbestos-like fiber. The 10 patients (six men, four women, aged 50 to 93) had surgery between 1996 and 2014 and were drawn from a larger series of 49. The authors stained the tissue for aquaporin-1 (AQP1), a water-channel protein. Overexpression was defined as membrane staining in 50% or more of tumor cells, and six of the 10 cases met that definition. These six had a mean overall survival of 26.3 months, compared with 8.9 months for the other four. The authors reported this difference as statistically significant (p less than 0.05). The hazard ratio they report, 1.492, had a 95% confidence interval of 0.432 to 5.153. No relationship emerged between AQP1 and other clinical and pathological features in these 10 patients. The authors concluded that AQP1 overexpression appeared promising for predicting outcome. They noted the small sample needs further validation and that disease stage was not available for all patients.

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 immunohistochemical study of archived tumor tissue, described as a preliminary report
• Who was studied: 10 patients with malignant pleural mesothelioma (6 men, 4 women; mean age 68.4, range 50 to 93), residents of Biancavilla or nearby areas in Sicily, Italy. These 10 underwent video-assisted thoracoscopic surgery between 1996 and 2014. They were selected from a larger series of 49 patients for whom clinical and follow-up data were available. Subtypes: 6 epithelioid, 1 sarcomatoid, 3 biphasic.
• Exposure: Environmental exposure to fluoro-edenite fibers, which the authors describe as asbestos-like. Fluoro-edenite was found in lava rock from a local quarry that was used for house and road construction. This study did not measure individual exposure levels.
• Main results:
  • Overexpression was defined as membranous staining in 50% or more of tumor cells. 6 of 10 cases (60%) met this definition. The other 4 of 10 (40%) showed negative staining or staining in fewer than 50% of tumor cells.
  • Patients with AQP1 in 50% or more of tumor cells had a mean overall survival of 26.3 months. Patients with AQP1 in fewer than 50% had 8.9 months. The abstract calls these figures medians.
  • The authors reported the survival difference between high and low AQP1 groups as statistically significant (p less than 0.05).
  • Univariate hazard ratio for the overexpression group was 1.492 (95% CI 0.432 to 5.153). In the multivariate model adjusting for age, sex and histologic subtype, the hazard ratio was 1.8 (95% CI 0.85 to 4.72).
  • In these 10 patients, no relationship emerged between AQP1 expression and other clinical and pathological variables.
  • All 10 cases stained positive for calretinin, cytokeratin 5/6 and WT1, which the authors took as confirming mesothelial origin. None stained for cytokeratin 7 or TTF1, which they took as excluding a lung origin.
• The authors' conclusion: The authors concluded that AQP1 overexpression appeared to be a promising prognostic tool for pleural mesothelioma patients. They described their study as the first report on AQP1 in mesothelioma related to environmental fluoro-edenite exposure, and said further validation in a larger cohort is needed.
• Limitations the authors state:
  • The number of patients was small, so further validation is needed.
  • Clinical stage could not be obtained for all patients, so AQP1 could not be assessed with correction for disease stage.

Topics

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

Medical terms in this study, explained in our Lexicon: fluoro-edenite, Malignant Mesothelioma, Pleural Mesothelioma, naturally occurring asbestos (NOA), Paraffin Block, Median Overall Survival.

Related studies

• Immunohistochemical Expression of Serine and Arginine-Rich Splicing Factor 1 (SRSF1) in Fluoro-Edenite-Induced Malignant Mesothelioma: A Preliminary Study — G. Broggi, G. Angelico, et al. (2021)
• Fibulin-3 immunoexpression in malignant mesothelioma due to fluoro-edenite: a preliminary report — R. Caltabiano, C. Loreto, et al. (2018)
• Immunohistochemical expression of retinoblastoma and phospho-retinoblastoma protein in sheep lung exposed to fluoro-edenite fibers — G. Musumeci, C. Loreto, et al. (2010)
• Pleural mesothelioma from fluoro-edenite exposure: PACAP and PAC1 receptor. A preliminary report — C. Lombardo, G. Maugeri, et al. (2024)
• Usefulness of Aquaporin 1 as a Prognostic Marker in a Prospective Cohort of Malignant Mesotheliomas — J. Driml, E. Pulford, et al. (2016)
• Mineral fibre toxicity: expression of retinoblastoma (Rb) and phospho-retinoblastoma (pRb) protein in alveolar epithelial and mesothelial cell lines exposed to fluoro-edenite fibres — G. Musumeci, V. Cardile, et al. (2011)

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