RESUMO
PURPOSE: In this report, we summarise data on BRCA1 gene analysis in Latvia to characterise criteria of genetic testing for breast and ovarian cancer susceptibility. MATERIAL/METHODS: Analysis by SSCP/HD, MALDI-TOF mass spectrometry or DNA sequencing was used for mutation detection. Mutations identified were confirmed by direct DNA sequencing. RESULTS: Out of 1068 breast and 231 ovarian cancer patients from different families: 58 carried the c.5266dupC and 43 carried the c.4035delA mutations. Every 4th patient in our study did not report cancer in the family. The breast cancer was diagnosed earlier in carriers of the c.5266dupC than in carriers of the c.4035delA (p=0.003). The incidence of breast or ovarian cancer does not differ among the 2 mutation carriers in our patient group. The nature of the c.5266dupC mutation might be more deleterious. CONCLUSIONS: We recommend the screening of 4 founder BRCA1 mutations in all breast and ovarian cancer patients in Latvia at diagnosis of disease regardless of family history or age. The BRCA1 screening can be carried out efficiently using the MALDI-TOF mass spectrometry mutation detection method developed in the Biomedical Research and Study Centre (Riga, Latvia).
Assuntos
Proteína BRCA1/genética , Neoplasias da Mama/genética , Predisposição Genética para Doença , Mutação/genética , Neoplasias Ovarianas/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Neoplasias da Mama/diagnóstico , Neoplasias da Mama/epidemiologia , DNA de Neoplasias/genética , Feminino , Seguimentos , Humanos , Letônia/epidemiologia , Pessoa de Meia-Idade , Neoplasias Ovarianas/diagnóstico , Neoplasias Ovarianas/epidemiologia , Reação em Cadeia da Polimerase , Polimorfismo Conformacional de Fita Simples , PrognósticoRESUMO
BACKGROUND: Mutations in the high penetrance breast and ovarian cancer susceptibility gene BRCA1 account for a significant percentage of hereditary breast and ovarian cancer cases. Genotype-phenotype correlations of BRCA1 mutations located in different parts of the BRCA1 gene have been described previously; however, phenotypic differences of specific BRCA1 mutations have not yet been fully investigated. In our study, based on the analysis of a population-based series of unselected breast and ovarian cancer cases in Latvia, we show some aspects of the genotype-phenotype correlation among the BRCA1 c.4034delA (4153delA) and c.5266dupC (5382insC) founder mutation carriers. METHODS: We investigated the prevalence of the BRCA1 founder mutations c.4034delA and c.5266dupC in a population-based series of unselected breast (n = 2546) and ovarian (n = 795) cancer cases. Among the BRCA1 mutation carriers identified in this analysis we compared the overall survival, age at diagnosis and family histories of breast and ovarian cancers. RESULTS: We have found that the prevalence of breast and ovarian cancer cases (breast: ovarian cancer ratio) differs significantly among the carriers of the c.5266dupC and c.4034delA founder mutations (OR = 2.98, 95%CI = 1.58 to 5.62, P < 0.001). We have also found a difference in the prevalence of breast and ovarian cancer cases among the 1st and 2nd degree relatives of the c.4034delA and c.5266dupC mutation carriers. In addition, among the breast cancer cases the c.4034delA mutation has been associated with a later age of onset and worse clinical outcomes in comparison with the c.5266dupC mutation. CONCLUSIONS: Our data suggest that the carriers of the c.4034delA and c.5266dupC founder mutations have different risks of breast and ovarian cancer development, different age of onset and prognosis of breast cancer.