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Somatic BRCA1 mutations in clinically sporadic breast cancer with medullary histological features


Rechsteiner, Markus; Dedes, Konstantin; Fink, Daniel; Pestalozzi, Bernhard; Sobottka, Bettina; Moch, Holger; Wild, Peter; Varga, Zsuzsanna (2018). Somatic BRCA1 mutations in clinically sporadic breast cancer with medullary histological features. Journal of Cancer Research and Clinical Oncology, 144(5):865-874.

Abstract

BACKGROUND: The role of somatic BRCA1/2 gene mutations in breast cancer is getting increasing attention in view of hereditary disease. The medullary phenotype and triple negative intrinsic subtypes are often, but not exclusively encountered in BRCA1 germline mutated breast cancer, whilst for BRCA2, no association to specific histological features are known. In this study, we addressed the relationship between morphological medullary phenotype and BRCA1/2 somatic mutations in breast cancer without known positive family anamnesis.
METHODS: 32 clinically sporadic breast cancers with medullary features were analyzed for somatic BRCA1/2 mutations (all coding exons) with next-generation sequencing technology. Paraffin-embedded formalin-fixed breast cancer samples from all patients were analyzed.
RESULTS: Three of 32 tumors (9%) had pathogenic (ARUP class-5) BRCA1 gene alterations. Two of these pathogenic variants exhibited deletions leading to frameshift mutations (p.Glu23fs, p.Val1234fs), and the remaining single-nucleotid-variant resulted in premature STOP codon (p.Glu60Ter). In one patient, the same pathogenic BRCA1 mutation was detected (p.Glu23fs) in normal breast tissue. Retrospective follow-up in two patients revealed a positive family history for breast cancer and consecutive germline mutation testing confirmed presence of BRCA1 mutations. No somatic pathogenic BRCA2 mutations were detected.
CONCLUSIONS: BRCA1 mutation testing may be useful in clinically sporadic breast cancer patients with medullary features to identify potential mutation carriers independently from intrinsic molecular subtype. Formalin-fixed paraffin-embedded cancer tissue can undergo testing within a routine molecular-diagnostic setting as a clinical BRCA1/2 mutation screening strategy.

Abstract

BACKGROUND: The role of somatic BRCA1/2 gene mutations in breast cancer is getting increasing attention in view of hereditary disease. The medullary phenotype and triple negative intrinsic subtypes are often, but not exclusively encountered in BRCA1 germline mutated breast cancer, whilst for BRCA2, no association to specific histological features are known. In this study, we addressed the relationship between morphological medullary phenotype and BRCA1/2 somatic mutations in breast cancer without known positive family anamnesis.
METHODS: 32 clinically sporadic breast cancers with medullary features were analyzed for somatic BRCA1/2 mutations (all coding exons) with next-generation sequencing technology. Paraffin-embedded formalin-fixed breast cancer samples from all patients were analyzed.
RESULTS: Three of 32 tumors (9%) had pathogenic (ARUP class-5) BRCA1 gene alterations. Two of these pathogenic variants exhibited deletions leading to frameshift mutations (p.Glu23fs, p.Val1234fs), and the remaining single-nucleotid-variant resulted in premature STOP codon (p.Glu60Ter). In one patient, the same pathogenic BRCA1 mutation was detected (p.Glu23fs) in normal breast tissue. Retrospective follow-up in two patients revealed a positive family history for breast cancer and consecutive germline mutation testing confirmed presence of BRCA1 mutations. No somatic pathogenic BRCA2 mutations were detected.
CONCLUSIONS: BRCA1 mutation testing may be useful in clinically sporadic breast cancer patients with medullary features to identify potential mutation carriers independently from intrinsic molecular subtype. Formalin-fixed paraffin-embedded cancer tissue can undergo testing within a routine molecular-diagnostic setting as a clinical BRCA1/2 mutation screening strategy.

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Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:04 Faculty of Medicine > University Hospital Zurich > Institute of Pathology and Molecular Pathology
Dewey Decimal Classification:610 Medicine & health
Language:English
Date:2018
Deposited On:12 Mar 2018 20:04
Last Modified:14 Apr 2018 01:03
Publisher:Springer
ISSN:0171-5216
OA Status:Hybrid
Free access at:Publisher DOI. An embargo period may apply.
Publisher DOI:https://doi.org/10.1007/s00432-018-2609-5
PubMed ID:29453630

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