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Subject: search.filters.subject.DNA Mutational Analysis

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    Germline CDH1 mutations are a significant contributor to the high frequency of early-onset diffuse gastric cancer cases in New Zealand Māori.
    (Springer Nature, 2018-03-27) Hakkaart C; Ellison-Loschmann L; Day R; Sporle A; Koea J; Harawira P; Cheng S; Gray M; Whaanga T; Pearce N; Guilford P
    New Zealand Māori have a considerably higher incidence of gastric cancer compared to non-Māori, and are one of the few populations worldwide with a higher prevalence of diffuse-type disease. Pathogenic germline CDH1 mutations are causative of hereditary diffuse gastric cancer, a cancer predisposition syndrome primarily characterised by an extreme lifetime risk of developing diffuse gastric cancer. Pathogenic CDH1 mutations are well described in Māori families in New Zealand. However, the contribution of these mutations to the high incidence of gastric cancer is unknown. We have used next-generation sequencing, Sanger sequencing, and Multiplex Ligation-dependent Probe Amplification to examine germline CDH1 in an unselected series of 94 Māori gastric cancer patients and 200 healthy matched controls. Overall, 18% of all cases, 34% of cases diagnosed with diffuse-type gastric cancer, and 67% of cases diagnosed aged less than 45 years carried pathogenic CDH1 mutations. After adjusting for the effect of screening known HDGC families, we estimate that 6% of all advanced gastric cancers and 13% of all advanced diffuse-type gastric cancers would carry germline CDH1 mutations. Our results demonstrate that germline CDH1 mutations are a significant contributor to the high frequency of diffuse gastric cancer in New Zealand Māori.
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    Identifying colorectal cancer caused by biallelic MUTYH pathogenic variants using tumor mutational signatures
    (Springer Nature Limited, 6/06/2022) Georgeson P; Harrison TA; Pope BJ; Zaidi SH; Qu C; Steinfelder RS; Lin Y; Joo JE; Mahmood K; Clendenning M; Walker R; Amitay EL; Berndt SI; Brenner H; Campbell PT; Cao Y; Chan AT; Chang-Claude J; Doheny KF; Drew DA; Figueiredo JC; French AJ; Gallinger S; Giannakis M; Giles GG; Gsur A; Gunter MJ; Hoffmeister M; Hsu L; Huang W-Y; Limburg P; Manson JE; Moreno V; Nassir R; Nowak JA; Obón-Santacana M; Ogino S; Phipps AI; Potter JD; Schoen RE; Sun W; Toland AE; Trinh QM; Ugai T; Macrae FA; Rosty C; Hudson TJ; Jenkins MA; Thibodeau SN; Winship IM; Peters U; Buchanan DD
    Carriers of germline biallelic pathogenic variants in the MUTYH gene have a high risk of colorectal cancer. We test 5649 colorectal cancers to evaluate the discriminatory potential of a tumor mutational signature specific to MUTYH for identifying biallelic carriers and classifying variants of uncertain clinical significance (VUS). Using a tumor and matched germline targeted multi-gene panel approach, our classifier identifies all biallelic MUTYH carriers and all known non-carriers in an independent test set of 3019 colorectal cancers (accuracy = 100% (95% confidence interval 99.87-100%)). All monoallelic MUTYH carriers are classified with the non-MUTYH carriers. The classifier provides evidence for a pathogenic classification for two VUS and a benign classification for five VUS. Somatic hotspot mutations KRAS p.G12C and PIK3CA p.Q546K are associated with colorectal cancers from biallelic MUTYH carriers compared with non-carriers (p = 2 × 10-23 and p = 6 × 10-11, respectively). Here, we demonstrate the potential application of mutational signatures to tumor sequencing workflows to improve the identification of biallelic MUTYH carriers.