RESUMO
BACKGROUND & AIMS: Multigene panels are commercially available tools for hereditary cancer risk assessment that allow for next-generation sequencing of numerous genes in parallel. However, it is not clear if these panels offer advantages over traditional genetic testing. We investigated the number of cancer predisposition gene mutations identified by parallel sequencing in individuals with suspected Lynch syndrome. METHODS: We performed germline analysis with a 25-gene, next-generation sequencing panel using DNA from 1260 individuals who underwent clinical genetic testing for Lynch syndrome from 2012 through 2013. All patients had a history of Lynch syndrome-associated cancer and/or polyps. We classified all identified germline alterations for pathogenicity and calculated the frequencies of pathogenic mutations and variants of uncertain clinical significance (VUS). We also analyzed data on patients' personal and family history of cancer, including fulfillment of clinical guidelines for genetic testing. RESULTS: Of the 1260 patients, 1112 met National Comprehensive Cancer Network (NCCN) criteria for Lynch syndrome testing (88%; 95% confidence interval [CI], 86%-90%). Multigene panel testing identified 114 probands with Lynch syndrome mutations (9.0%; 95% CI, 7.6%-10.8%) and 71 with mutations in other cancer predisposition genes (5.6%; 95% CI, 4.4%-7.1%). Fifteen individuals had mutations in BRCA1 or BRCA2; 93% of these met the NCCN criteria for Lynch syndrome testing and 33% met NCCN criteria for BRCA1 and BRCA2 analysis (P = .0017). An additional 9 individuals carried mutations in other genes linked to high lifetime risks of cancer (5 had mutations in APC, 3 had bi-allelic mutations in MUTYH, and 1 had a mutation in STK11); all of these patients met NCCN criteria for Lynch syndrome testing. A total of 479 individuals had 1 or more VUS (38%; 95% CI, 35%-41%). CONCLUSIONS: In individuals with suspected Lynch syndrome, multigene panel testing identified high-penetrance mutations in cancer predisposition genes, many of which were unexpected based on patients' histories. Parallel sequencing also detected a high number of potentially uninformative germline findings, including VUS.
Assuntos
Biomarcadores Tumorais/genética , Neoplasias Colorretais Hereditárias sem Polipose/genética , Testes Genéticos/métodos , Mutação em Linhagem Germinativa , Adulto , Neoplasias Colorretais Hereditárias sem Polipose/diagnóstico , Análise Mutacional de DNA , Feminino , Perfilação da Expressão Gênica , Frequência do Gene , Predisposição Genética para Doença , Hereditariedade , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Masculino , Pessoa de Meia-Idade , Linhagem , Fenótipo , Valor Preditivo dos Testes , Medição de Risco , Fatores de RiscoRESUMO
OBJECTIVES: Patients with hereditary cancer syndromes are at high risk for a second primary cancer. Early identification of these patients after an initial cancer diagnosis is the key to implementing cancer risk-reducing strategies. METHODS: A commercial laboratory database was searched for women with a history of both breast and ovarian or colorectal and endometrial cancer who underwent genetic testing for hereditary breast and ovarian cancer (HBOC) or Lynch syndrome (LS). RESULTS: Among women with both breast and ovarian cancer, 22.4% (2,237/9,982) had a BRCA1 or BRCA2 mutation. Among women with both colorectal and ovarian cancer, 28.1% (264/941) had a mutation associated with LS. In 66.6% of BRCA1 or BRCA2 mutation carriers and in 58.3% of LS mutation carriers, >5 years passed between the cancer diagnoses. Of patients with HBOC and LS, 56 and 65.2%, respectively, met the National Comprehensive Cancer Network guidelines for hereditary cancer testing after their initial diagnosis based on their personal cancer history alone. CONCLUSIONS: A substantial number of women tested for LS or HBOC after being diagnosed with two successive primary cancers were diagnosed with a hereditary cancer syndrome. In many cases, the time interval between the diagnoses was long enough to allow for the implementation of surveillance and/or prophylactic measures.
Assuntos
Biomarcadores Tumorais/genética , Neoplasias Colorretais Hereditárias sem Polipose/genética , Predisposição Genética para Doença , Mutação/genética , Síndromes Neoplásicas Hereditárias/genética , Neoplasias Ovarianas/genética , Proteínas Adaptadoras de Transdução de Sinal/genética , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Proteína BRCA1/genética , Proteína BRCA2/genética , Neoplasias da Mama/diagnóstico , Neoplasias da Mama/genética , Criança , Pré-Escolar , Neoplasias Colorretais Hereditárias sem Polipose/diagnóstico , Feminino , Seguimentos , Testes Genéticos , Heterozigoto , Humanos , Lactente , Recém-Nascido , Masculino , Pessoa de Meia-Idade , Proteína 1 Homóloga a MutL , Proteína 2 Homóloga a MutS/genética , Síndromes Neoplásicas Hereditárias/diagnóstico , Proteínas Nucleares/genética , Neoplasias Ovarianas/diagnóstico , Prognóstico , Estudos Retrospectivos , Adulto JovemRESUMO
BACKGROUND: This study assessed BRCA1 and BRCA2 mutation prevalence in an unselected cohort of patients with triple-negative breast cancer (BC). METHODS: One hundred ninety-nine patients were enrolled. Triple negativity was defined as <1% estrogen and progesterone staining by immunohistochemistry and HER-2/neu not overexpressed by fluorescence in situ hybridization. Having given consent, patients had BRCA1 and BRCA2 full sequencing and large rearrangement analysis. Mutation prevalence was assessed among the triple-negative BC patients and the subset of patients without a family history of breast/ovarian cancer. Independent pathological review was completed on 50 patients. RESULTS: Twenty-one deleterious BRCA mutations were identified--13 in BRCA1 and 8 in BRCA2 (prevalence, 10.6%). In 153 patients (76.9%) without significant family history (first-degree or second-degree relatives with BC aged <50 years or ovarian cancer at any age), 8 (5.2%) mutations were found. By using prior National Comprehensive Cancer Network (NCCN) guidelines recommending testing for triple-negative BC patients aged <45 years, 4 of 21 mutations (19%) would have been missed. Two of 21 mutations (10%) would have been missed using updated NCCN guidelines recommending testing for triple-negative BC patients aged <60 years. CONCLUSIONS: The observed mutation rate was significantly higher (P = .0005) than expected based on previously established prevalence tables among patients unselected for pathology. BRCA1 mutation prevalence was lower, and BRCA2 mutation prevalence was higher, than previously described. Additional mutation carriers would have met new NCCN testing guidelines, underscoring the value of the updated criteria. Study data suggest that by increasing the age limit to 65 years, all carriers would have been identified.