Heterozygous germline BLM mutations increase susceptibility to asbestos and mesothelioma

Angela Bononi, Keisuke Goto, Guntulu Ak, Yoshie Yoshikawa, Mitsuru Emi, Sandra Pastorino, Lorenzo Carparelli, Angelica Ferro, Masaki Nasu, Jin-Hee Kim, Joelle S Suarez, Ronghui Xu (+15 others)
2020 Proceedings of the National Academy of Sciences of the United States of America  
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
more » ... 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.
doi:10.1073/pnas.2019652117 pmid:33318203 fatcat:lbxy3rp3kbcvhmrxm2p36cfhpi