Prevalence of BRCA1 and BRCA2 mutations in Korean breast cancer patients

The Effects of National Insurance Coverage Expansion and Genetic Counseling's Role on BRCA1/2 Mutation Tests in Breast Cancer Patients

PURPOSE

This study aims to evaluate the impact of South Korea's national insurance coverage (NIC) expansion and the addition of genetic counselors on BRCA1/2 mutation testing rates in breast cancer patients.

MATERIALS AND METHODS

A retrospective review was conducted at the Samsung Medical Center (SMC), dividing patients into three groups: pre-NIC expansion, post-NIC expansion, and post-extra genetic counselor involvement. The number of BRCA1/2 tests performed and the detection rates among newly diagnosed and follow-up patients, particularly focusing on triple-negative breast cancer (TNBC) cases, were analyzed.

RESULTS

Post-NIC expansion, there was a significant increase in BRCA1/2 testing rates, with a gradual rise in detection rates while maintaining statistical significance. TNBC patients under 60 experienced substantial increases in testing rates. The number of follow-up patients recalled for testing also rose significantly after the extra genetic counselor involvement. Additionally, NIC expansion increased insurance coverage for TNBC patients, enhancing accessibility to testing.

CONCLUSION

The study highlights the positive impact of NIC expansion and genetic counselor involvement on BRCA1/2 mutation testing rates and subsequent patient management. Addressing financial barriers to testing and incorporating genetic counseling significantly improve patient outcomes. This model provides a potential strategy for enhancing early detection and personalized treatment for breast cancer patients with BRCA1/2 mutations, contributing to global cancer management efforts.

The power of the Risk of Ovarian Malignancy Algorithm considering menopausal status: a comparison with CA 125 and HE4

Objective

To identify the power of tumor markers for predicting ovarian cancer according to menopausal status.

Methods

The medical records of 876 women with ovarian cysts were retrospectively reviewed. Cancer antigen 125 (CA 125), human epididymis protein 4 (HE4), and Risk of Ovarian Malignancy Algorithm (ROMA) were analyzed. Sensitivity, specificity, and the receiver operating characteristic (ROC) curve analyses of these tumor markers were evaluated.

Results

The sensitivity of ROMA was 66.7% and the specificity was 86.8% to detect ovarian malignancy. The patients were divided into 2 groups according to menopausal status: premenopause (n=532, 60.7%) and postmenopause (n=344, 39.3%). For diagnostic accuracy, ROMA was lower than HE4 in premenopausal women (82.7% vs. 91.4%) and lower than CA 125 in postmenopausal women (86.9% vs. 88.7%). The ROC curve analysis revealed that the power of ROMA was not significantly better than that of HE4 in premenopausal women (area under the curve [AUC], 0.731 vs. 0.732, p=0.832), and it was also not significantly better than that of CA 125 in postmenopausal women (AUC, 0.871 vs. 0.888, p=0.440).

Conclusion

The discrimination power of tumor markers for ovarian cancer was different according to menopausal status. In predicting ovarian malignancy, ROMA was neither superior to HE4 in premenopausal women nor superior to CA 125 in postmenopausal women.

Multi-omics profiling of younger Asian breast cancers reveals distinctive molecular signatures

Breast cancer (BC) in the Asia Pacific regions is enriched in younger patients and rapidly rising in incidence yet its molecular bases remain poorly characterized. Here we analyze the whole exomes and transcriptomes of 187 primary tumors from a Korean BC cohort (SMC) enriched in pre-menopausal patients and perform systematic comparison with a primarily Caucasian and post-menopausal BC cohort (TCGA). SMC harbors higher proportions of HER2+ and Luminal B subtypes, lower proportion of Luminal A with decreased ESR1 expression compared to TCGA. We also observe increased mutation prevalence affecting BRCA1, BRCA2, and TP53 in SMC with an enrichment of a mutation signature linked to homologous recombination repair deficiency in TNBC. Finally, virtual microdissection and multivariate analyses reveal that Korean BC status is independently associated with increased TIL and decreased TGF-β signaling expression signatures, suggesting that younger Asian BCs harbor more immune-active microenvironment than western BCs.

While breast cancer incidence in the Asia Pacific region is rising, the molecular basis remains poorly characterized. Here the authors perform genomic screening of 187 Korean breast cancer patients and find differences in molecular subtype distribution, mutation pattern and prevalence, and gene expression signature when compared to TCGA.

BRCA1 mutation spectrum, functions, and therapeutic strategies: The story so far

BRCA1 gene mutations account for about 25-28% of hereditary Breast Cancer as BRCA1 is included in the category of high penetrance genes. Except for few commonmutations, there is a heterogenous spectrum of BRCA1 mutations in various ethnic groups. 185AGdel and 5382ins Care the most common BRCA1 alterations (founder mutations) which have been identified in most of the population. This review has been compiled with an aim to consolidate the information on genetic variants reported in BRCA1 found in various ethnic groups, their functional implications if known; involvement of BRCA1 in various cellular pathways/processes and potential BRCA1 targeted therapies. The pathological variations of BRCA1 vary among different ethical groups. A systematic search in PubMed and Google scholar for the literature on BRCA1 gene was carried out to figure out structure and function of BRCA1 gene. BRCA1 is a large protein having 1863 amino acids with multiple functional domains and interacts with multiple proteins to carry out various crucial cellular processes. BRCA1 plays a major role in maintaining genome integrity, transcription regulation, chromatin remodeling, cell cycle checkpoint control, DNA damage repair, chromosomal segregation, and apoptosis. Studies investigating the phenotypic response of mutant BRCA1 protein and comparing it to wildtype BRCA1 protein are clinically important as they are involved in homologous recombination and other repair mechanisms. These studies may help in developing more targetted therapies, detecting novel interacting partners, identification of new signaling pathways that BRCA1 is a part of or downstream target genes that BRCA1 affects.

A Pilot Study on Screening of BRCA1 Mutations (185delAG, 1294del40) in Nepalese Breast Cancer Patients

BACKGROUND

Breast cancer is the second most common malignancy among Nepalese women, accounting for 60% of the total cancer cases in females. Women diagnosed with germline mutations in BRCA1 like 185delAG, 1294del40 develop breast and/or ovarian cancer with a lifelong likelihood of up to 85% whereas presence of a mutation increases the risk for mutations to occur in other genes. The major objective of this study was to find the prevalence of these mutations in Nepalese cancer patients.

MATERIALS AND METHODS

This prospective study was carried out at two cancer hospitals in the Kathmandu valley over a period of 11 months. Irrespective of age group and stage of canceran appropriate amount of blood was withdrawn from 50 breast cancer patients and 20 controls. DNA was extracted manually and subjected to PCR using primers for 185delAG and 1294del40 mutations. PCR products were then digested with restriction enzyme (DdeII) followed by electrophoresis.

RESULTS

Prevalence of 185delAG in reference breast cancer patients was found to be 4/50 (8%) but no 1294del40 was apparent.

CONCLUSIONS

Several mutations occurring in different exons of BRCA1 as well as mutations in other genes like BRCA2, for example, should also be taken in account.

The cancer genetics and pathology of male breast cancer

Male breast cancer (MBC) is an uncommon and poorly understood disease. Recent molecular studies have shown important differences from female breast cancer which are likely to influence treatment strategies from the current female-based management towards a more tailored approach. Significantly more MBCs than female breast cancers arise with an underlying germline cancer predisposition, and display a vastly different penetrance compared with females. Furthermore, the genophenotypical association of basal-like cancer with BRCA1 present in female breast cancer is not observed in male breast cancer. Differences in somatic changes between male and female breast cancer have also been reported, with particular enrichment of PIK3CA mutations and a paucity of TP53 mutations. In general, chromosomal-based changes, in particular regions of gains, are seen more frequently in male than female breast cancer and methylation is seen less frequently. Clinically, several molecular subtypes with prognostic relevance have been described, including chromosomal complex high and methylation high groups, and subgroups with profiling signatures pertaining to epithelial mesenchymal transition and hormonal therapy insensitivity. As with female breast cancer, attention to male specific multicentre trials based on the individual characteristics are needed, together with establishment of reliable preclinical models to understand more clearly the pathogenesis of male breast cancer and improve the general poor outcome of this disease.

The biological effects and clinical implications of BRCA mutations: where do we go from here?

BRCA1 and BRCA2 are tumour-suppressor genes encoding proteins that are essential for the repair of DNA double-strand breaks by homologous recombination (HR). Cells that lack either BRCA1 or BRCA2 repair these lesions by alternative, more error-prone mechanisms. Individuals carrying germline pathogenic mutations in BRCA1 or BRCA2 are at highly elevated risk of developing breast and/or ovarian cancer. Genetic testing for germline pathogenic mutations in BRCA1 and BRCA2 has proved to be a valuable tool for determining eligibility for cancer screening and prevention programmes. In view of increasing evidence that the HR DNA repair pathway can also be disrupted by sequence variants in other genes, screening for other BRCA-like defects has potential implications for patient care. Additionally, there is a growing argument for directly testing tumours for pathogenic mutations in BRCA1, BRCA2 and other genes involved in HR-DNA repair as inactivation of these genes may be strictly somatic. Tumours in which HR-DNA repair is altered are most likely to respond to emerging targeted therapies, such as inhibitors of poly-ADP ribose polymerase. This review highlights the biological role of pathogenic BRCA mutations and other associated defects in DNA damage repair mechanisms in breast and ovarian cancer, with particular focus on implications for patient management strategies.

Comprehensive spectrum of BRCA1 and BRCA2 deleterious mutations in breast cancer in Asian countries

Approximately 5%-10% of breast cancers are due to genetic predisposition caused by germline mutations; the most commonly tested genes are BRCA1 and BRCA2 mutations. Some mutations are unique to one family and others are recurrent; the spectrum of BRCA1/BRCA2 mutations varies depending on the geographical origins, populations or ethnic groups. In this review, we compiled data from 11 participating Asian countries (Bangladesh, Mainland China, Hong Kong SAR, Indonesia, Japan, Korea, Malaysia, Philippines, Singapore, Thailand and Vietnam), and from ethnic Asians residing in Canada and the USA. We have additionally conducted a literature review to include other Asian countries mainly in Central and Western Asia. We present the current pathogenic mutation spectrum of BRCA1/BRCA2 genes in patients with breast cancer in various Asian populations. Understanding BRCA1/BRCA2 mutations in Asians will help provide better risk assessment and clinical management of breast cancer.

Unique features of young age breast cancer and its management

Young age breast cancer (YABC) has unique clinical and biological features that are not seen in older patients. Breast tumor biology is more aggressive and is associated with an unfavorable prognosis in younger women. The diagnosis of breast cancer is often delayed, resulting in their initial presentation with more advanced disease. Together, these characteristics lead to a poorer prognosis in younger women than in older women. Young women who receive breast-conserving therapy have a higher rate of local recurrence. Therefore, it is important to secure sufficient resection margins and consider boost radiotherapy to prevent local treatment failure. Based on age alone, patients with YABC should be regarded as high-risk cases, and they should be treated with adjuvant chemotherapy. Special considerations regarding psychosocial factors and fertility should be taken into account for young patients. This review discusses the major considerations and principles concerning the management of patients with YABC.

Novel Germline Mutation of BRCA1 Gene in a 56-Year-Old Woman with Breast Cancer, Ovarian Cancer, and Diffuse Large B-Cell Lymphoma

We report a case of a 56-year-old woman with breast cancer, ovarian cancer, and diffuse large B-cell lymphoma with a BRCA1 gene mutation. Evidence is mounting that there is a large increase in the risk for hematologic malignancies among patients with genetic changes in the BRCA pathways. The genomic analysis demonstrated a frameshift mutation in the BRCA1 gene: 277_279delinsCC (Phe93fs). It is a novel BRCA1 mutation that has never been reported, and caused malignant lymphoma as well as breast and ovarian cancer.

The prevalence of BRCA mutations among familial breast cancer patients in Korea: results of the Korean Hereditary Breast Cancer study

The primary aim of this study was to estimate the prevalence of BRCA1/2 mutations among familial breast cancer (BC) patients in Korea. We analyzed 775 familial BC patients who were enrolled in the Korean Hereditary Breast Cancer (KOHBRA) study and treated at 36 institutions between May 2007 and May 2010. Patients with familial BC were defined as BC patients with family histories of BC or ovarian cancer (OC) in any relatives. All probands received genetic counseling and BRCA genetic testing was performed after obtaining informed consent. The mean age of BC diagnosis was 43.6 years. The numbers of probands with family histories of BC only and OC only were 682 and 93, respectively. The overall prevalence of the BRCA mutation among familial BC patients was 21.7 % (BRCA1 9.3 % and BRCA2 12.4 %). Subgroup analyses observed prevalences of the BRCA mutation as follows: 19.6 % among patients with BC family history only (BRCA1 7.6 % and BRCA2 12.0 %) and 36.6 % among patients with OC family history only (BRCA1 21.5 % and BRCA2 15.1 %). Most of the subgroups satisfied the 10 % probability criteria to undergo BRCA testing. However, the prevalence of the BRCA mutations among subgroups that had 2 BC patients in a family with both age at diagnosis of more than 50 years old did not reach the 10 % criteria (4.1 %). Korean familial BC patients are good candidates for BRCA testing even when they have family histories of single breast cancers. However, proband age at diagnosis should be carefully considered when selecting patients for testing.

Prevalence of BRCA1 and BRCA2 Germline Mutations in Breast Cancer Women of Multiple Ethnic Region in Northwest China

PURPOSE

The aim of this study is to further understand the status of BRCA1 and BRCA2 mutation among Chinese high-risk breast cancer patients in multiple-ethnic regions of China.

METHODS

A total of 79 blood samples of high-risk breast cancer patients from Xinjiang Uyghur autonomous region were analyzed by PCR-DHPLC sequencing analysis.

RESULTS

Analysis with full length of the two genes identified a total of 6 deleterious mutations (2073delA, 2394C-T [Q759X] and IVS16+1G>A in BRCA1; 1627A-T [K467X], 6873delCTCC and 9481delA in BRCA2) in this cohort. The prevalence of BRCA1/2 germline mutation was about 7.6% (6/79) in the Xinjiang multiple ethnic region of China. Among them, 3 novel deleterious mutations, 2073delA in BRCA1 (Han ethnic Chinese) and BRCA2 variants 6873delCTCC and 9481delA (both are Kazakh ethnic Chinese), were identified and they had never been reported in breast cancer information core (BIC) database before. 2394C-T (Q759X) and IVS16+1G>A, in BRCA1 and BRCA2 variants 1627A-T were previously reported in other populations but not Chinese. Among 6 of the BRCA-related tumors, three BRCA1- and one BRCA2-associated tumors were in triple negative (estrogen receptor, progesterone receptor, and HER2 negative expressed) status and exhibited a high tumor grade. So far none of these 6 deleterious mutations were reported in ethnic Han Chinese.

CONCLUSION

BRCA germline mutation in Chinese multiple ethnicity region may exhibit different genotypes compared to ethnic Han Chinese in other regions. These differences may arise from interaction of genetic background and environmental factors.

Prevalence of BRCA1 and BRCA2 mutations in non-familial breast cancer patients with high risks in Korea: the Korean Hereditary Breast Cancer (KOHBRA) Study

Prevalence and phenotype of BRCA mutation can vary by race. The purpose of this study is to evaluate the prevalence of BRCA1/2 mutations in non-familial breast cancer patients with high risks in Korea. A subset of 758 patients was selected for this study from the KOHBRA nationwide multicenter prospective cohort study. Mutations in BRCA1/2 genes were tested using fluorescent-conformation sensitive gel electrophoresis, denaturing high performance liquid chromatography or direct sequencing. Mutation of BRCA1/2 genes were identified in 65 (8.6%) patients among total 758 patients [BRCA1 mutation: 25 (3.3%), BRCA2 mutation: 40 (5.3%)]. According to risk groups, mutation of BRCA1/2 genes were identified in 53 (8.5%) of 625 early onset patients (age ≤ 40), in 22 (17.7%) of 124 bilateral breast cancer patients, in 3 (50.0%) of 6 breast and ovarian cancer patients, in one (5.9%) of 17 male breast cancer patients, in 5 cases (7.6%) of 66 multiple organ cancer patients. The most common mutation was 509C>A for BRCA1 and 7708C>T for BRCA2. The prevalence of BRCA1/2 mutations by age in early onset patients was significantly different (age <35 vs age ≥35; 10.0 vs 2.9%, p = 0.0007). BRCA1/2 mutations for non-familial Korean breast cancer patients were detected at a high rate, particularly, in patients with early onset of less than 35 years of age, bilateral breast cancer, and breast and ovarian cancer. Individualized genetic counseling should be offered for non-familial breast cancer patients with these risk factors.

Characteristics of double heterozygosity for BRCA1 and BRCA2 germline mutations in Korean breast cancer patients

To investigate clinical, pathological, and familial characteristics of Korean patients with double heterozygosity for BRCA1 and BRCA2 mutations, six breast tumors of five patients who carried deleterious mutations in both of the genes were included. Medical records of the patients were reviewed and genetic testing by direct sequencing was undertaken to detect mutations in BRCA1 and BRCA2. Seven frameshift and three nonsense mutations were identified, and four mutations are novel in the Breast Cancer Information Core. There were no Ashkenazi founder mutations detected. The mean age at diagnosis for breast cancer was 33 years. All six tumors were infiltrating ductal carcinoma and poorly differentiated. Pathologic stage was I or II, and immunohistochemistry showed negative immunoreactivity for estrogen receptor and Her-2/neu in all tumors. Positive immunoreactivity for progesterone receptor was found only in one tumor. Three patients had familial history of breast, ovarian or other cancers. One patient who was diagnosed for breast cancer at the age of 26 had two maternal family members of metachronous bilateral breast cancer. Another patient who experienced metachronous bilateral breast cancer had maternal history of ovarian and esophageal cancer. In summary, Korean patients with double heterozygosity for BRCA1 and BRCA2 were young at diagnosis of breast cancer. Tumors were early stage, high grade, and almost triple-negative phenotype. All familial history of breast, ovary or other cancer was maternal. Close surveillance and accurate risk assessment should be provided for the patients with mutations in the both of the genes.

Ultrasound and clinicopathological characteristics of triple receptor-negative breast cancers

Purpose

Triple receptor-negative (TRN) breast cancer is associated with high risk of recurrence and poor prognosis. The present study assessed the clinicopathologic characteristics and ultrasound (US) features of TRN breast cancers.

Methods

Pathological and biological data were reviewed for 558 breast cancer patients treated at Kangbuk Samsung Hospital, between January 2003 and December 2009. The patients were separated into TRN breast cancer and non-TRN breast cancer groups, based on the results of immunohistochemical prognostic panels. Clinical and pathologic features were compared for the two groups. US features, including shape, orientation, margins, boundaries, echo patterns, posterior acoustic features, surrounding tissues, and microcalcifications, were determined for 41 TRN patients and 189 non-TRN controls (ER+/PR+/HER2-).

Results

Of 558 cases, 58 (10.4%) had the TRN phenotype. Four hundred and thirty-four cases (77.8%) were invasive ductal carcinomas. TRN cancer was significantly associated with specific characteristics of tumor size, nuclear grade, histologic grade, venous invasion, and lymphatic invasion. With respect to US features, TRN cancers were more likely to have an oval shape, a circumscribed margin, and marked hypoechogenicity.

Conclusion

Tumor characteristics were different between TRN and non-TRN breast cancers, although US cannot differentiate the subtype of breast cancers TRN cancer tend to show somewhat different US morphology.

PALB2 mutations 1592delT and 229delT are not present in Korean breast cancer patients negative for BRCA1 and BRCA2 mutations

PALB2 is a recently discovered breast cancer susceptibility gene, and mutations in the gene have been demonstrated to confer about twofold higher risk of breast cancer. Truncating mutations in PALB2 gene have been identified in varied populations. However, PALB2's significance to breast cancer has not been investigated in the Korean population. In this study, we evaluated the frequency of PALB2 1592delT and 229delT mutations in 300 Korean breast cancer patients diagnosed with either familial or early-onset breast cancer. All patients were confirmed negative for BRCA1 and BRCA2 mutations. Neither 1592delT nor 229delT mutations was found in any of the study cohort. Our results imply that these mutations are absent or rare in Korean patients who are negative for BRCA1 and BRCA2 mutations. We found no evidence to recommend screening for these mutations in the Korean population. However, PALB2 mutations have been demonstrated infrequent and inhomogeneous across investigated populations. Thus, screening the whole PALB2 gene for novel mutations is required to elucidate its significance in predisposition to breast cancer in Korean women.

BRCA1 and BRCA2 germline mutations in Korean ovarian cancer patients

PURPOSE

To evaluate the proportion of Korean ovarian cancer patients with a strong family history and the genetic status in such patients.

METHODS AND PATIENTS

Pedigree analysis and genetic counseling were performed on 337 ovarian cancer patients in the National Cancer Center Korea between January 2005 and June 2008. Patients with a strong family history were defined as (1) patients with double primary ovarian and breast cancer and (2) ovarian cancer patients with one or more first-degree relatives with breast or ovarian cancer. Lymphocyte specimens from peripheral blood were processed for BRCA1 and BRCA2 by direct sequencing.

RESULTS

Sixteen percent (54/337) of patients had a strong family history. Of the 54 patients with a strong family history, 40 patients (74%) accepted the genetic test. Thirteen deleterious mutations (11 in BRCA1 and 2 in BRCA2) were identified (33%). Twenty-three of 283 patients (8%) without a strong family history underwent genetic testing and two deleterious mutations in BRCA1 were identified (9%). Eight of 15 mutations (53%) were novel, and c.1041delAGCinsT and c.2081insC in the BRCA1 gene were recurrent in two patients.

CONCLUSIONS

The proportion of Korean ovarian cancer patients with a strong family history was significant, and the prevalence of BRCA1 and BRCA2 mutations in such patients was high.

Contribution of BRCA1 germline mutation in patients with sporadic breast cancer

Hereditary artifacts in BRCA1 gene have a significant contributory role in familial cases of breast cancer. However, its germline mutational penetrance in sporadic breast cancer cases with respect to Pakistani population has not yet been very well defined. This study was designed to assess the contributory role of germline mutations of this gene in sporadic cases of breast cancer. 150 cases of unilateral breast cancer patients, with no prior family history of breast cancer and no other disorders or diseases in general with age range 35–75 yrs, were included in this study.

Mutational analysis for hot spots on Exon 2, 3 and 13 of BRCA1 was done by using Single Strand Conformational Polymorphism (SSCP). Sequence analysis revealed five variants (missense) and one novel splice site mutation at exon 13. No germline mutation was observed on the remaining exons with respect sporadic breast cancer cases in Pakistani population. A vast majority of breast cancer cases are sporadic; the present study may be helpful for designing a better genetic screening tool for germline BRCA mutations in sporadic breast cancer patients of Pakistani population. Further studies involving a screening of entire coding region of BRCA1 is required to explore the merits of genetic diagnosis and counseling in breast cancer patients.

The CHEK2 1100delC mutation is not present in Korean patients with breast cancer cases tested for BRCA1 and BRCA2 mutation

The germline CHEK2 1100delC mutation is a low penetrance breast cancer susceptibility allele, frequently observed in patient with family history of breast cancer and/or young age and the frequency varied according to race or ethnicity. In this study, we evaluated the significance of CHEK2 1100delC in predisposition to breast cancer by assessing its frequency in a material of 493 Korean breast cancer patients who had been screened for BRCA1 and BRCA2 mutations (42 patients had deleterious mutation of BRCA1/2). Mutation detection of CHEK2 1100delC was based upon analysis of primer extension products generated for previously amplified genomic DNA using a chip based MALDI-TOP mass spectrometry platform. After overall measurement automatically, assays which had bad peaks were checked again manually. None of the 493 Korean patients with breast cancer who were candidate for BRCA1 and BRCA2 test carried the 1100delC mutation observed in Caucasians with limited frequency. In the previous studies, we observed higher or comparable prevalence of BRCA1 and BRCA2 mutations in Korean patients with breast cancer compared to Caucasian breast cancer population. In the present study, we evaluated the role of a CHEK2 1100delC as a susceptibility mutation of breast cancer in the Korean population. However, our results suggest that this mutation is absent or may be very infrequent in Korean patients with breast cancer who have high risk of BRCA1 and BRCA2 mutation, making its screening irrelevant from the practical point view.

The prevalence of BRCA1 and BRCA2 germline mutations in high-risk breast cancer patients of Chinese Han nationality: two recurrent mutations were identified

To have an overview of the role of BRCA1 and BRCA2 genes among Chinese high-risk breast cancer patients, we analyzed 489 such high-risk breast cancer patients from four breast disease clinical centers in China, by using PCR-DHPLC or SSCP-DNA sequencing analysis. Allelotype analysis was done at five short tandem repeat (STR) markers in or adjacent to BRCA1 on the recurrent mutation carriers. For those analyzed both genes, 8.7% of early-onset breast cancer cases and 12.9% of familial breast cancer cases had a BRCA1 or BRCA2 mutation, as compared with the 26.1% of cases with both early-onset breast cancer and affected relatives. For those reporting malignancy family history other than breast/ovarian cancer, the prevalence of BRCA1/2 mutation is about 20.5%, and it was significantly higher than the patients only with family history of breast/ovarian cancer (P = 0.02). The family history of ovarian cancer (26.7% vs. 11.9%) and stomach cancer (23.8% vs. 11.8%) doubled the incidence of BRCA1/2, but the difference did not reach the statistical significance. Two recurrent mutations in BRCA1, 1100delAT and 5589del8, were identified. The recurrent mutations account for 34.8% BRCA1 mutations in our series. Similar allelotypes were detected in most STR status for those harboring the same mutations. The BRCA1 associated tumors were more likely to exhibit a high tumor grade, negative C-erbB-2/neu status and triple negative (ER, PgR and C-erbB-2/neu negative) status (P < 0.05). We recommended the BRCA1 and BRCA2 genetic analysis could be done for high-risk breast cancer patient in Chinese population, especially for those with both early-onset breast cancer and affected relatives. There may be some degree of shared ancestry for the two recurrent BRCA1 mutations in Chinese.

Breast cancer screening for Korean women must consider traditional risks as well as two genetic risk factors: genetic polymorphisms and inheritable gene mutations

Asian women worldwide have increasing rates of breast cancer due to acculturation which may be altering, gene to gene and/or, genetic and environmental interactions at the cellular level. The purpose of this integrative review is to alert nurses and physicians to rising rates of breast cancer among Korean women and to a need for breast health screening programs in the United States that are more culturally responsive and attentive to the effects of acculturation and genetic risk factors. A comprehensive review of the English and Korean literature pertaining to rising incidence of breast cancer among Korean women in their homeland and in the United States is retraced since 1983. Korean women in Korea and in the United States face similar barriers to cancer screening services. Korean women need knowledge about the effect of acculturation on breast cancer risk and patterns of familial inheritance of breast cancer. Screening is especially important among younger women (younger than age 35), those with a strong family history, and women in community settings where acculturation has its greatest impact. Nurse clinicians and researchers who aim to improve breast cancer screening among minority women must pay closer attention to these risk factors and design culturally competent services and evaluation research. In the United States and Korea, Korean nurses are needed to specialize in breast cancer screening as well as cancer genetic risk assessment and genetic counseling.

Mutation analysis of BRCA1 and BRCA2 from 793 Korean patients with sporadic breast cancer

To investigate the role of BRCA1 and BRCA2 mutations in Korean patients with sporadic breast cancer, 793 breast cancer patients were analyzed by denaturing high performance liquid chromatography and direct sequencing. The 793 breast cancer patients enrolled in this study had no family history of affected first- or second-degree relatives with breast and/or ovarian cancer. Seventy-nine different sequence variations were identified, of which 34 were novel. Fifteen deleterious mutations were detected in 20 out of 793 patients (2.5%): 11 frameshift mutations and 4 nonsense mutations (seven in BRCA1 and eight in BRCA2), and no recurrent or founder mutations were observed in BRCA mutation screening. However, three mutations (K467X, 3972delTGAG, and R2494X in BRCA2) were identified in other studies of the Korean population. Of 793 patients, the clinicopathological information was obtained in 135 patients, who included 20 deleterious mutation-positive and 115 deleterious mutation-negative groups. The median age at diagnosis, histologic type, histologic grade and T stage did not show statistically significant difference between these two groups. BRCA-mutation-associated tumors showed lower estrogen receptor, progesterone receptor, and HER-2/neu but higher p53 expression. Although poor prognostic features were noted in BRCA-associated tumors, we did not find statistically significant differences. The present study will be helpful in the evaluation of the need for the genetic screening of germline BRCA mutations and reliable genetic counseling for sporadic breast cancer patients.

Array-based mutation detection of BRCA1 using direct probe/target hybridization

We describe here an efficient microarray-based multiplex assay to detect Korean-specific mutations in breast cancer susceptibility gene BRCA1 using direct probe/target hybridization. Allele-specific oligonucleotides were covalently immobilized on an aldehyde-activated glass slide to prepare an oligonucleotide chip. From a wild-type sample, a two-step method was used to generate labeled multiplex polymerase chain reaction (PCR) amplification products of genomic regions containing the mutation sites. Amino allyl-dUTP, an amine-modified nucleotide, was incorporated during multiplex PCR amplifications and a monofunctional form of cyanine 3 dye was subsequently attached to the reactive amine group of the PCR products. Hybridization of the labeled PCR products to the oligonucleotide chip successfully identified all of the genotypes for the selected mutation sites. This work demonstrates that oligonucleotides chip-based analysis is a good candidate for efficient clinical testing for BRCA1 mutations when combined with the indirect strategy to prepare labeled target samples.