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Supplementary Material for: Gastric Cancer in BRCA1 Germline Mutation Carriers: Results of Endoscopic Screening and Molecular Analysis of Tumor Tissues

posted on 06.11.2020, 09:30 by Avanesyan A.A., Sokolenko A.P., Ivantsov A.O., Kleshchev M.A., Maydin M.A., Bizin I.V., Raskin G.A., Shelekhova K.V., Gorodnova T.V., Bessonov A.A., Anisimova E.I., Volynshchikova O.A., Romanko A.A., Ni V.I., Broyde R.V., Tkachenko O.B., Whitehead A.J., Scherbakov A.M., Imyanitov E.N.
Introduction: There is some evidence suggesting a link between BRCA1/2 germline mutations and increased risk of gastric cancer. Methods: Endoscopic screening for stomach malignancies was performed in 120 BRCA1 mutation carriers in order to evaluate the probability of detecting the tumor disease. Results: No instances of gastric cancer were revealed at the first visit. The analysis of atrophic changes performed by OLGA (Operative Link for Gastritis Assessment) criteria revealed that OLGA stages I–IV alterations were observed in 26 of 41 (63%) subjects aged >50 years as compared to 29 of 79 (37%) in younger subjects (p = 0.007, χ2 test). One BRCA1 mutation carrier developed gastric cancer 4 years after the first visit for endoscopic examination. We performed next-generation sequencing analysis for this tumor and additional 4 archival gastric cancers obtained from BRCA1/2 mutation carriers. Somatic loss of the remaining BRCA1/2 allele was observed in 3 out of 5 tumors analyzed; all of these carcinomas, but none of the malignancies with the retained BRCA1/2 copy, showed chromosomal instability. Conclusion: Taken together, these data justify further studies on the relationships between the BRCA1/2 and gastric cancer.