RESUMEN
OBJECTIVE: The goal of this work was to evaluate the importance of genetic factors in the etiology of fallopian tube cancer. METHODS: All pathologically confirmed cases of fallopian tube cancer diagnosed in Ontario from 1990 to 1998 were identified from the records of the Ontario Cancer Registry. Living patients were approached to provide information about their family history and to provide a blood sample for testing for mutations in BRCA1 and BRCA2. RESULTS: A modest increase in the risk of ovarian cancer (relative risk (RR) = 2.2; 95% confidence interval (CI) = 0.4, 6.3) and of early-onset breast cancer (RR = 2.4; 95% CI = 0.6, 6.1) was observed in the first-degree relatives of the fallopian cancer cases. Five of the forty-four cases were positive for a mutation in BRCA1 (11%) and two were positive for a BRCA2 mutation (5%). Five of eighteen women diagnosed at or before age 55 were positive (28%). Two of the seven mutation carriers had a strong family history of breast and ovarian cancer, and three carriers had a modest family history. Three of the forty-four cases were Jewish, and of these, two carried a founder mutation characteristic of this population. CONCLUSIONS: Fallopian tube carcinoma should be considered to be a clinical component of the hereditary breast-ovarian cancer syndrome, and may be associated with BRCA1 and BRCA2 mutations. Genetic evaluation should be offered to women who present with fallopian tube carcinoma. It is important to consider the risk of fallopian tube carcinoma when prophylactic oophorectomy is performed in high-risk women.
Asunto(s)
Neoplasias de las Trompas Uterinas/genética , Genes BRCA1/genética , Proteínas de Neoplasias/genética , Factores de Transcripción/genética , Adulto , Anciano , Proteína BRCA2 , Neoplasias de la Mama/epidemiología , Neoplasias de la Mama/genética , Neoplasias de las Trompas Uterinas/epidemiología , Femenino , Humanos , Persona de Mediana Edad , Mutación , Ontario/epidemiología , Neoplasias Ováricas/epidemiología , Neoplasias Ováricas/genética , LinajeRESUMEN
A population-based series of 649 unselected incident cases of ovarian cancer diagnosed in Ontario, Canada, during 1995-96 was screened for germline mutations in BRCA1 and BRCA2. We specifically tested for 11 of the most commonly reported mutations in the two genes. Then, cases were assessed with the protein-truncation test (PTT) for exon 11 of BRCA1, with denaturing gradient gel electrophoresis for the remainder of BRCA1, and with PTT for exons 10 and 11 of BRCA2. No mutations were found in all 134 women with tumors of borderline histology. Among the 515 women with invasive cancers, we identified 60 mutations, 39 in BRCA1 and 21 in BRCA2. The total mutation frequency among women with invasive cancers, 11.7% (95% confidence interval [95%CI] 9.2%-14.8%), is higher than previous estimates. Hereditary ovarian cancers diagnosed at age <50 years were mostly (83%) due to BRCA1, whereas the majority (60%) of those diagnosed at age >60 years were due to BRCA2. Mutations were found in 19% of women reporting first-degree relatives with breast or ovarian cancer and in 6.5% of women with no affected first-degree relatives. Risks of ovarian, breast, and stomach cancers and leukemias/lymphomas were increased nine-, five-, six- and threefold, respectively, among first-degree relatives of cases carrying BRCA1 mutations, compared with relatives of noncarriers, and risk of colorectal cancer was increased threefold for relatives of cases carrying BRCA2 mutations. For carriers of BRCA1 mutations, the estimated penetrance by age 80 years was 36% for ovarian cancer and 68% for breast cancer. In breast-cancer risk for first-degree relatives, there was a strong trend according to mutation location along the coding sequence of BRCA1, with little evidence of increased risk for mutations in the 5' fifth, but 8.8-fold increased risk for mutations in the 3' fifth (95%CI 3.6-22.0), corresponding to a carrier penetrance of essentially 100%. Ovarian, colorectal, stomach, pancreatic, and prostate cancer occurred among first-degree relatives of carriers of BRCA2 mutations only when mutations were in the ovarian cancer-cluster region (OCCR) of exon 11, whereas an excess of breast cancer was seen when mutations were outside the OCCR. For cancers of all sites combined, the estimated penetrance of BRCA2 mutations was greater for males than for females, 53% versus 38%. Past studies may have underestimated the contribution of BRCA2 to ovarian cancer, because mutations in this gene cause predominantly late-onset cancer, and previous work has focused more on early-onset disease. If confirmed in future studies, the trend in breast-cancer penetrance, according to mutation location along the BRCA1 coding sequence, may have significant impact on treatment decisions for carriers of BRCA1-mutations. As well, BRCA2 mutations may prove to be a greater cause of cancer in male carriers than previously has been thought.
Asunto(s)
Genes BRCA1 , Mutación de Línea Germinal , Proteínas de Neoplasias/genética , Neoplasias/epidemiología , Neoplasias Ováricas/genética , Factores de Transcripción/genética , Proteína BRCA2 , Neoplasias de la Mama/epidemiología , Neoplasias de la Mama/genética , Etnicidad , Familia , Femenino , Humanos , Incidencia , Masculino , Neoplasias/genética , Ontario , Neoplasias Ováricas/epidemiología , Factores de RiesgoRESUMEN
BACKGROUND: The association between BRCA1 germ-line mutations and breast cancer prognosis is controversial. A historical cohort study was designed to determine the prognosis for women with axillary lymph node negative hereditary breast cancer. PATIENTS AND METHODS: We tested pathology blocks from 118 Ashkenazi Jewish women with axillary lymph node negative breast cancer for the presence of the two common BRCA1 founder mutations, 185delAG and 5382insC. Patients were followed up for a median of 76 months. Somatic TP53 mutations were screened for by immunohistochemistry, and direct sequencing was performed in the BRCA1-positive tumours. RESULTS: Sixteen breast cancer blocks (13.6%) carried a BRCA1 mutation. Young age of onset, high nuclear grade, negative estrogen receptor status and over-expression of p53 were highly associated with BRCA1-positive status (P-values all <0.01). BRCA1 mutation carriers had a higher mortality than non-carriers (five-year overall survival, 50% and 89.6%, respectively, P = 0.0001). Young age of onset, estrogen receptor negative status, nuclear grade 3, and over-expression of p53 also predicted a poor outcome. Cox multivariate analyses showed that only germ-line BRCA1 mutation status was an independent prognostic factor for overall survival (P = 0.01). Among nuclear grade 3 tumours, the BRCA1 mutation carrier status was a significant prognostic factor of death (risk ratio 5.8, 95% confidence interval: 1.5-22, P = 0.009). Sequencing of BRCA1-related breast cancers revealed one TP53 missense mutation not previously reported in breast cancer. CONCLUSIONS: Using a historical cohort approach, we have identified BRCA1 mutation status as an independent prognostic factor for node negative breast cancer among the Ashkenazi Jewish women. Those managing women carrying a BRCA1 mutation may need take these findings into consideration. Additionally, our preliminary results, taken together with the work of others suggest a different carcinogenic pathway in BRCA1-related breast cancer, compared to non-hereditary cases.
Asunto(s)
Neoplasias de la Mama/genética , Genes BRCA1/genética , Genes p53/genética , Mutación de Línea Germinal , Adulto , Factores de Edad , Anciano , Proteína BRCA2 , Neoplasias de la Mama/mortalidad , Estudios de Cohortes , Femenino , Humanos , Judíos/genética , Ganglios Linfáticos/patología , Persona de Mediana Edad , Análisis Multivariante , Proteínas de Neoplasias/genética , Pronóstico , Modelos de Riesgos Proporcionales , Factores de Riesgo , Análisis de Supervivencia , Factores de Transcripción/genéticaRESUMEN
Mutations of the BRCA1 and BRCA2 genes account for approximately 80% of hereditary breast/ovarian cancer families, but the size of these two genes makes mutation analysis time-consuming and technically challenging. In some populations such as the Ashkenazi Jewish and the French-Canadian, a small number of recurrent founder mutations account for the majority of mutations in cancer families. We have therefore developed two rapid genetic screening tests, which allow us to detect three frequent frameshift mutations in the Ashkenazi Jewish population and five frameshift mutations in the French-Canadian population. These fluorescent non-radioactive methods permit the simultaneous detection of multiple mutations by generating multiplexed PCR-amplified gene fragments, and by discriminating these on the basis of their size in a denaturing polyacrylamide gel. Using these methods, we were able to correctly identify all mutants in a blinded analysis of 276 DNA samples, including 30 derived from paraffin-embedded tumor samples and 10 from buccal-cell brushes, with no false positive or false negative results. These techniques designed for the direct detection of recurrent mutations in the BRCA1 and BRCA2 genes, have the advantages of being efficient, sensitive, cost-effective, and are applicable to large scale screening for epidemiologic studies.
Asunto(s)
Efecto Fundador , Genes BRCA1/genética , Pruebas Genéticas/métodos , Mutación , Proteínas de Neoplasias/genética , Reacción en Cadena de la Polimerasa/métodos , Factores de Transcripción/genética , Proteína BRCA2 , Neoplasias de la Mama/diagnóstico , Neoplasias de la Mama/genética , Canadá , Electroforesis en Gel de Poliacrilamida , Exones , Femenino , Humanos , Judíos , Mucosa Bucal/metabolismoAsunto(s)
Proteínas de Neoplasias/genética , Proteínas de Fusión Oncogénica , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Niño , Preescolar , Subunidad alfa 2 del Factor de Unión al Sitio Principal , Supervivencia sin Enfermedad , Femenino , Humanos , Lactante , Masculino , Fenotipo , Leucemia-Linfoma Linfoblástico de Células Precursoras/tratamiento farmacológico , Resultado del TratamientoRESUMEN
A predominant mutation within the BRCA1 predisposition gene, 185delAG, has been detected in about 1% of the Ashkenazi population, considered a high-risk group for breast and ovarian cancers. We examined 639 unrelated healthy Jews of Iraqi extraction, a presumed low-risk group, for the existence of this mutation. Three individuals were identified as 185delAG mutation carriers, and haplotype analysis of the Iraqi mutation carriers revealed that 2 of the Iraqis shared a common haplotype with 6 Ashkenazi mutation carriers, and 1 had a haplotype which differed by a single marker. This study suggests that the BRCA1 185delAG mutation also occurs in populations considered at low-risk for breast and ovarian cancers, and that it might have occurred prior to the dispersion of the Jewish people in the Diaspora, at least at the time of Christ.