BRCA1 and BRCA2 germline mutation analysis among Indian women from south India: identification of four novel mutations and high-frequency occurrence of 185delAG mutation (original) (raw)
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Germline BRCA1 Mutation Analysis in Indian Breast/Ovarian Cancer Families
Cancer Biology & Therapy, 2002
Most of the predisposition to hereditary breast and ovarian cancer has been attributed to inherited defects in two tumor suppressor genes BRCA1 and BRCA2. To explore the contribution of BRCA1 mutations to hereditary breast cancer among Indian women, we examined the coding sequence of the BRCA1 gene in 14 breast cancer patients with a positive family history of breast and/or ovarian cancer. Mutation analysis was carried out using conformation sensitive gel electrophoresis (CSGE) followed by sequencing. Three mutations (21%) in the BRCA1 gene were identified. Two of them are novel mutations of which one is a missense mutation in exon 7 near the RING finger domain, while the other is a one base pair deletion in exon 11 which results in protein truncation. The third mutation, 185delAG, has been previously described in Ashkenazi Jewish families. To our knowledge this is the first report of a study of germline BRCA1 mutation analysis in familial breast cancer in India. Our data from 14 different families suggests a lower prevalence but definite involvement of germline mutations in the BRCA1 gene among Indian women with breast cancer and a family history of breast cancer.
Cancer Management and Research, 2018
Background: The spectrum of BRCA mutations that predispose to development of breast/ ovarian cancer in Indian population remains unexplored. We report incidence and various types of pathogenic, likely pathogenic and variants of unknown significance (VUS) mutations in BRCA1 and BRCA2 genes observed at a tertiary cancer center in North India. Materials and methods: A total of 206 unrelated breast and/or ovarian cancer patients, who met the National Comprehensive Cancer Network (NCCN) guidelines for genetic testing, were screened for germline BRCA1/BRCA 2 mutations on high-throughput sequencing platform; large genomic rearrangements were assessed by multiple ligation probe assay. Mutations were mined in mutational databases, PubMed, and discerned into classes. Furthermore, the clinicopathological correlation of BRCA mutation status with prognostic markers in breast cancer and tumor histology in ovarian cancer was performed. Results: In total, 45/206 and 17/206 cases showed positivity for BRCA1 and BRCA2 mutations, respectively, whereas 1/206 was positive for a mutation in both the genes. Altogether, 33 distinct BRCA1 mutations were observed, among which 27 were deleterious (12 frameshifts, 8 nonsense, 1 missense, 3 splice-site variants, 2 big deletions and 1 large duplication) and 6 were VUS. Five novel BRCA1 mutations (c.541G>T, c.1681delT, c.2295delG, c.4915C>T and exon 23 deletion) were identified. Seven mutations (c.2214_2215insT, c.2295delG, c.3607C>T, c.4158_4162delCTCTC, c.4571C>A, splicesite_3 (C>T) and exon 21-23 duplication) occurred more than once, whereas 16 distinct BRCA2 mutations were noted-9 were lethal (6 frameshifts, 2 nonsense and 1 big deletion) and 7 VUS. One unique pathogenic BRCA2 mutation (c.932_933insT) was recognized. Two mutations (c.9976A>T and c.10089A>G) recurred twice. No significant difference in hormone receptor status was observed among BRCA1 carriers, BRCA2 carriers and noncarriers. Conclusion: We have documented various pathogenic and VUS mutations in BRCA1 and BRCA2 genes observed in the cohort. Six novel mutations were identified. The knowledge shared would assist genetic testing in enabling more focused site-specific screening for mutations in biological relatives.
Cancer Management and Research
Background: The spectrum of BRCA mutations that predispose to development of breast/ ovarian cancer in Indian population remains unexplored. We report incidence and various types of pathogenic, likely pathogenic and variants of unknown significance (VUS) mutations in BRCA1 and BRCA2 genes observed at a tertiary cancer center in North India. Materials and methods: A total of 206 unrelated breast and/or ovarian cancer patients, who met the National Comprehensive Cancer Network (NCCN) guidelines for genetic testing, were screened for germline BRCA1/BRCA 2 mutations on high-throughput sequencing platform; large genomic rearrangements were assessed by multiple ligation probe assay. Mutations were mined in mutational databases, PubMed, and discerned into classes. Furthermore, the clinicopathological correlation of BRCA mutation status with prognostic markers in breast cancer and tumor histology in ovarian cancer was performed. Results: In total, 45/206 and 17/206 cases showed positivity for BRCA1 and BRCA2 mutations, respectively, whereas 1/206 was positive for a mutation in both the genes. Altogether, 33 distinct BRCA1 mutations were observed, among which 27 were deleterious (12 frameshifts, 8 nonsense, 1 missense, 3 splice-site variants, 2 big deletions and 1 large duplication) and 6 were VUS. Five novel BRCA1 mutations (c.541G>T, c.1681delT, c.2295delG, c.4915C>T and exon 23 deletion) were identified. Seven mutations (c.2214_2215insT, c.2295delG, c.3607C>T, c.4158_4162delCTCTC, c.4571C>A, splicesite_3 (C>T) and exon 21-23 duplication) occurred more than once, whereas 16 distinct BRCA2 mutations were noted-9 were lethal (6 frameshifts, 2 nonsense and 1 big deletion) and 7 VUS. One unique pathogenic BRCA2 mutation (c.932_933insT) was recognized. Two mutations (c.9976A>T and c.10089A>G) recurred twice. No significant difference in hormone receptor status was observed among BRCA1 carriers, BRCA2 carriers and noncarriers. Conclusion: We have documented various pathogenic and VUS mutations in BRCA1 and BRCA2 genes observed in the cohort. Six novel mutations were identified. The knowledge shared would assist genetic testing in enabling more focused site-specific screening for mutations in biological relatives.
Current Oncology, 2014
Objectives: It is estimated that 1–2% of individuals of Ashkenazi Jewish (AJ) ancestry carry one of three pathogenic founder mutations in BRCA1 and BRCA2. Targeted testing for these mutations (BRCA1 187delAG and 5385insC, and BRCA2 6174delT) is therefore recommended for all AJ breast and ovarian cancer patients, regardless of age of diagnosis or family history. Comprehensive analysis of both genes is recommended for a subset of AJ patients in whom founder mutations are not identified, but estimates of the yield from comprehensive analysis in this population vary widely. Methods: We sought to establish the proportion of non-founder mutations in AJ patients undergoing clinical testing in our laboratory from January 2006 through August 2013. Analysis included AJ patients for whom: (1) comprehensive testing was ordered as the initial test, or (2) founder mutation testing was ordered with instructions to “reflex” to comprehensive analysis if negative. The latter group was limited to case...
Journal of Medical Genetics, 2005
A recent report estimated the breast cancer risks in carriers of the three Ashkenazi founder mutations to be higher than previously published estimates derived from population based studies. In an attempt to confirm this, the breast and ovarian cancer risks associated with the three Ashkenazi founder mutations were estimated using families included in a previous meta-analysis of populatrion based studies. The estimated breast cancer risks for each of the founder BRCA1 and BRCA2 mutations were similar to the corresponding estimates based on all BRCA1 or BRCA2 mutations in the meta-analysis. These estimates appear to be consistent with the observed prevalence of the mutations in the Ashkenazi Jewish population. W e recently reported the average risks of breast and ovarian cancer associated with BRCA1 and BRCA2 mutations, using a meta-analysis of pedigree data from 498 BRCA1 and BRCA2 mutation carriers identified through population based studies of women with breast and ovarian cancer. 1 King et al 2 estimated the risks to carriers in the three Ashkenazi founder mutations (BRCA1 185delAG and 5382insC, and BRCA2 6174delT) by genotyping the relatives of 104 mutation carriers. They concluded that the risks are higher than both our estimates or other previously published estimates. 3-6 To provide a more direct comparison between the two studies, we estimated the breast and ovarian cancer risks associated with the three Ashkenazi founder mutations using families included in our meta-analysis.
Acta biochimica Polonica, 2002
Germline mutations in the BRCA1 or BRCA2 genes predispose their carriers to breast or/and ovary cancers during their lifetime. The most frequent mutations: 5382insC, 185delAG, C61G and 4153delA in BRCA1, and 6174delT and 9631delC in BRCA2 were studied in a group of 148 probands admitted for genetic counseling, using allele-specific amplification (ASA) PCR test. Fifteen carriers of three different mutations: 5382insC, 185delAG and C61G in BRCA1 were found. Two families carried the 185delAG mutation and additional two C61G in BRCA1. Nobody carried the mutation 4153delA in BRCA1 nor 6174delT or 9631delC in BRCA2. Most of the carriers of a germline mutation were observed among the patients who developed bilateral breast cancer (17%). The lowest frequency of the germline mutations was found in the healthy persons who had two or more relatives affected with breast or ovarian cancer.
The Importance of a Family History of Breast Cancer in Predicting the Presence of a BRCA Mutation
The American Journal of Human Genetics, 1999
et al (1997) The founder mutations 185delAG and 5382insC in BRCA1 and 6174delT in BRCA2 appear in 60% of ovarian cancer and 30% of earlyonset breast cancer patients among Ashkenazi women. Am J Hum Genet 60:505-514 Baker RJ, Nelder JA (1978) The GLIM system, release 3: generalized linear interactive modelling. Numerical Algorithms Group, Oxford Couch FJ, DeShano ML, Blackwood MA, Calzone K, Stopfer J, Campeau L, Ganguly A, et al (1997) BRCA1 mutation in women attending clinics that evaluate the risk of breast cancer. N Engl J Med 336:1409-1415 Hartge P, Struewing JP, Wacholder S, Brody LC, Tucker, MA (1999) The prevalence of common BRCA1 and BRCA2 mutations among Ashkenazi Jews. Am J Hum Genet 64: 963-970 Hopper JL, Southey MC, Dite GS, Jolley DJ, Giles GG, McCredie MRE, Easton DF,and the Australian Breast Cancer Family Study (1999) Population-based estimate of the average age-specific cumulative risk of breast cancer for a defined set of protein-truncating mutations in BRCA1 and BRCA2. Cancer Epidemiol Biomarker Prevent 8:741-747 McCullagh P, Nelder JA (1983) Generalized linear models. Easton DF, et al (1999) Prevalence of BRCA1 and BRCA2 gene mutations in patients with early-onset breast cancer. J Natl Cancer Inst 91:943-949 Shattuck-Eidens D, Oliphant A, McClure M, McBride C, Gupte J, Rubano T, Pruss D, et al (1997) BRCA1 sequence analysis in women at high risk for susceptibility mutations: risk factor analysis and implications for genetic testing. JAMA 278:1242-1250 Struewing JP, Hartge P, Wacholder S, Baker SM, Berlin M, McAdams M, Timmerman MM, et al (1997) The risk of cancer associated with specific mutations of BRCA1 and BRCA2 among Ashkenazi Jews. N Engl J Med 336:
Jugoslovenska medicinska biohemija, 2004
Hereditary breast and ovarian cancer syndromes can be caused by loss-of-function germline mutations in one of the tumor suppressor genes BRCA1 and BRCA2. In order to characterize these mutations in the Greek population we have been collecting samples from breast/ovarian cancer patients with a family history in collaboration with a large number of Greek Hospitals. Our DNA bank contains samples from more than 300 patients, corresponding to approximately 250 families. In terms of family history this group consists of three subgroups: (I) very early onset (<30 yrs) without family history (10%); (II) moderate family history (2 members affected, < 50 yrs) (40 %) (III) strong family history (3?7 members affected) (50 %). Screening of BRCA1 and BRCA2 genes in 150 patients has revealed deleterious mutations in 39 unrelated patients. 5382insC has been found in 11 unrelated families. In summary, the mutation spectrum of BRCA1 and BRCA2 genes in the Greek population seems to be composed b...
Human Mutation, 2004
The two major hereditary breast/ovarian cancer predisposition tumor suppressor genes, BRCA1 and BRCA2 that perform apparently generic cellular functions nonetheless cause tissue-specific syndromes in the human population when they are altered, or mutated in the germline. However, little is known about the contribution of BRCA1 and BRCA2 mutations to breast and/or ovarian cancers in the Indian population. We have screened for mutations the entire BRCA1 and BRCA2 coding sequences, and intron-exon boundaries, as well as their flanking intronic regions in sixteen breast or breast and ovarian cancer families of Indian origin. We have also analyzed 20 female patients with sporadic breast cancer regardless of age and family history, and 69 unrelated normal individuals as control. Thus a total of 154 samples were screened for BRCA1 and BRCA2 mutations using a combination of polymerase chain reaction-mediated site directed mutagenesis (PSM), polymerase chain reaction-single stranded conformation polymorphism assay (PCR-SSCP) and direct DNA sequencing of PCR products (DS). Twenty-one sequence variants including fifteen point mutations were identified. Five deleterious pathogenic, protein truncating frameshift and nonsense mutations were detected in exon 2 (c.187_188delAG); and exon 11 (c.3672G>T) [p.Glu1185X] of BRCA1 and in exon 11 (c.5227dupT, c.5242dupT, c.6180dupA) of BRCA2 (putative mutations-four novel) as well as fourteen amino acid substitutions were identified. Twelve BRCA1 and BRCA2 missense variants were identified as unique and novel. In the cohort of 20 sporadic female patients no mutations were found.
BRCA1 and BRCA2 gene mutations and risk of breast cancer
American Journal of Preventive Medicine, 1999
Breast cancer is the most common cancer and the second most common cause of cancer death among U.S. women. In 1998, about 178,700 new cases will be diagnosed and 43,500 women will die from the disease. Mutations in the BRCA1 gene, which was cloned in 1994 and is located on chromosome 17q, have been identified as causes of predisposition to breast, ovarian, and other cancers. A second breast cancer gene, BRCA2, has been localized to chromosome 13q. Using inferential procedures, the overall carrier frequency of BRCA1 gene mutations has been estimated at 1 in 500 in the general U.S. population. Recent studies have indicated that the carrier frequency of a specific BRCA1 allele, the 185delAG mutation, may be as high as 0.8% to 1% among women of Ashkenazi Jewish descent. Conclusions: Due to the proliferation of laboratories offering genetic tests for breast cancer susceptibility, their appropriate use in public health needs careful scrutiny. Several issues are raised when such genetic tests are considered for population-based prevention programs for breast cancer. Public health agencies, such as the Centers for Disease Control and Prevention, are important to monitoring and evaluating genetic testing done outside of research protocols. If genetic tests for breast cancer are to be incorporated into future prevention programs, evaluation is needed of whether the testing can have the intended effect. Medical Subject Headings (MeSH): breast cancer, BRCA1, cancer genetics, genetic testing, germline mutation, ovarian cancer, screening (Am J Prev Med 1999;16(2):91-98) Relatively few estimates of the carrier frequency of BRCA1 or BRCA2 gene mutations among women in the Am J Prev Med 1999;16(2) 93