Heterozygous germline BLM mutations increase susceptibility to asbestos and mesothelioma
Menée à partir du séquençage de l'ADN de 155 patients atteints d'un mésothéliome et menée à l'aide de modèles murins, cette étude met en évidence un mécanisme par lequel des mutations constitutionnelles hétérozygotes du gène BML sensibilisent les cellules mésothéliales à l'amiante et favorisent le développement d'un mésothéliome
We found that the probability of carrying heterozygous germline BLM mutations is significantly higher among mesothelioma patients than in the general population. In vitro and in vivo experiments suggest that heterozygous BLM mutations increase susceptibility to mesothelioma. BLM-mutation carriers are at higher risk of developing mesothelioma, and their risk increases upon asbestos exposure. Therefore, BLM mutation carriers should benefit from prevention and screening for early detection. We suggest that genetic testing to identify carriers of BLM heterozygous mutations and genetic counseling would help identify individuals at higher risk of mesothelioma and provide mutation carriers the option to implement simple preventive measures to reduce exposure to asbestos and other carcinogenic fibers to decrease their risk of developing mesothelioma.Rare biallelic BLM gene mutations cause Bloom syndrome. Whether BLM heterozygous germline mutations (BLM+/−) cause human cancer remains unclear. We sequenced the germline DNA of 155 mesothelioma patients (33 familial and 122 sporadic). We found 2 deleterious germline BLM+/− mutations within 2 of 33 families with multiple cases of mesothelioma, one from Turkey (c.569_570del; p.R191Kfs*4) and one from the United States (c.968A>G; p.K323R). Some of the relatives who inherited these mutations developed mesothelioma, while none with nonmutated BLM were affected. Furthermore, among 122 patients with sporadic mesothelioma treated at the US National Cancer Institute, 5 carried pathogenic germline BLM+/− mutations. Therefore, 7 of 155 apparently unrelated mesothelioma patients carried BLM+/− mutations, significantly higher (P = 6.7E-10) than the expected frequency in a general, unrelated population from the gnomAD database, and 2 of 7 carried the same missense pathogenic mutation c.968A>G (P = 0.0017 given a 0.00039 allele frequency). Experiments in primary mesothelial cells from Blm+/− mice and in primary human mesothelial cells in which we silenced BLM revealed that reduced BLM levels promote genomic instability while protecting from cell death and promoted TNF-α release. Blm+/− mice injected intraperitoneally with asbestos had higher levels of proinflammatory M1 macrophages and of TNF-α, IL-1β, IL-3, IL-10, and IL-12 in the peritoneal lavage, findings linked to asbestos carcinogenesis. Blm+/− mice exposed to asbestos had a significantly shorter survival and higher incidence of mesothelioma compared to controls. We propose that germline BLM+/− mutations increase the susceptibility to asbestos carcinogenesis, enhancing the risk of developing mesothelioma.All study data are included in the article and SI Appendix.