Hereditary breast cancer in the Han Chinese population

Analyzing the effects of BRCA1/2 variants on mRNA splicing by minigene assay

As BRCA1/2 gene sequencing become more extensive, a large number VUS (variants of uncertain significance) emerge rapidly. Verifying the splicing effect is an effective means for VUS reclassification. The Minigene Assay platform was established and its reliability was verified in this article. 47 BRCA1 or BRCA2 variants were selected and performed to validate their effect on mRNA splicing. The results showed that, a total of 16 variants were experimentally proved to have effects on mRNA splicing, among which 14 variants were shown to cause truncated proteins by Sanger sequencing. While the other two variants, BRCA2 c.7976 + 3 A > G and BRCA1 c.5152 + 3_5152 + 4insT was analyzed to cause 57 bp and 26 bp base in-frame deletion, respectively. The remaining 31 variants were not shown to cause mRNA splicing abnormity, including several sites at the edge of exons, which were predicted to affect splicing of mRNA by multiple bioinformatic software. Based on our experimental results, 37 variants were reclassified by ACMG rules. Our study showed that experimental splicing analysis was effectual for variants classification, and multiple functional assay or clinical data were also necessary for comprehensive judgment of variants.

Comparison of endocrine therapy and chemotherapy as different systemic treatment modes for metastatic luminal HER2-negative breast cancer patients —A retrospective study

Purpose

The purpose of this study was to evaluate endocrine therapy and chemotherapy for first-line, maintenance, and second-line treatment of hormone receptor-positive HER-2-negative metastatic breast cancer (HR+HER-2-MBC) and the relationship between different treatment options and survival.

Patients and methods

The patients included in this study were all diagnosed with metastatic breast cancer (MBC) at Shandong Cancer Hospital from January 2013 to June 2017. Of the 951 patients with MBC, 307 patients with HR+HER-2-MBC were included in the analysis. The progression-free survival (PFS) and overall survival (OS) of the various treatment modes were evaluated using Kaplan–Meier analysis and the log-rank test. Because of the imbalance in data, we used the synthetic minority oversampling technique (SMOTE) algorithm to oversample the data to increase the balanced amount of data.

Results

This retrospective study included 307 patients with HR+HER-2-MBC; 246 patients (80.13%) and 61 patients (19.87%) were treated with first-line chemotherapy and first-line endocrine therapy, respectively. First-line endocrine therapy was better than first-line chemotherapy in terms of PFS and OS. After adjusting for known prognostic factors, patients receiving first-line chemotherapy had poorer PFS and OS outcomes than patients receiving first-line endocrine therapy. In terms of maintenance treatment, the endocrine therapy-endocrine therapy maintenance mode achieved the best prognosis, followed by the chemotherapy-endocrine therapy maintenance mode and chemotherapy-chemotherapy maintenance mode, and the no-maintenance mode has resulted in the worst prognosis. In terms of first-line/second-line treatment, the endocrine therapy/endocrine therapy mode achieved the best prognosis, while the chemotherapy/chemotherapy mode resulted in the worst prognosis. The chemotherapy/endocrine therapy mode achieved a better prognosis than the endocrine therapy/chemotherapy mode. There were no significant differences in the KI-67 index (<15%/15-30%/≥30%) among the patients receiving first-line treatment modes, maintenance treatment modes, and first-line/second-line treatment modes. There was no statistical evidence in this study to support that the KI-67 index affected survival. However, in the first-line/second-line model, after SMOTE, we could see that KI-67 ≥ 30% had a poor prognosis.

Conclusions

Different treatment modes for HR+HER-2-MBC were analyzed. Endocrine therapy achieved better PFS and OS outcomes than chemotherapy. Endocrine therapy should be the first choice for first-line, maintenance, and second-line treatment of HR+HER-2-MBC.

Development and Validation of a New Multiparametric Random Survival Forest Predictive Model for Breast Cancer Recurrence with a Potential Benefit to Individual Outcomes

Purpose

Breast cancer (BC) is a multi-factorial disease. Its individual prognosis varies; thus, individualized patient profiling is instrumental to improving BC management and individual outcomes. An economical, multiparametric, and practical model to predict BC recurrence is needed.

Patients and Methods

We retrospectively investigated the clinical data of BC patients treated at the Third Affiliated Hospital of Sun Yat-sen University and Liuzhou Women and Children’s Medical Center from January 2013 to December 2020. Random forest-recursive feature elimination (run by R caret package) was used to determine the best variable set, and the random survival forest method was used to develop a predictive model for BC recurrence.

Results

The training and validations sets included 623 and 151 patients, respectively. We selected 14 variables, the pathological (TNM) stage, gamma-glutamyl transpeptidase, total cholesterol, Ki-67, lymphocyte count, low-density lipoprotein, age, apolipoprotein B, high-density lipoprotein, globulin, neutrophil count to lymphocyte count ratio, alanine aminotransferase, triglyceride, and albumin to globulin ratio, using random survival forest (RSF)-recursive feature elimination. We developed a recurrence prediction model using RSF. Using area under the receiver operating characteristic curve and Kaplan–Meier survival analyses, the model performance was determined to be accurate. C-indexes were 0.997 and 0.936 for the training and validation sets, respectively.

Conclusion

The model could accurately predict BC recurrence. It aids clinicians in identifying high-risk patients and making treatment decisions for Breast cancer patients in China. This new multiparametric RSF model is instrumental for breast cancer recurrence prediction and potentially improves individual outcomes.

Prevalence of hereditary breast and ovarian cancer (HBOC) predisposition gene mutations among 882 HBOC high-risk Chinese individuals

Identification of deleterious variants in hereditary breast and ovarian cancer (HBOC) susceptibility genes allows for increased clinical surveillance and early detection, and could predict the response to poly (ADP‐ribose) polymerase (PARP) inhibitor in patients with advanced ovarian carcinomas. To determine the prevalence and clinical prediction factors for HBOC syndrome, 882 selected individuals underwent multigene panel testing for HBOC risk assessment during the period from January 2015 to March 2018. Overall, 176 deleterious mutations were observed in 19.50% (n = 172) of individuals. Twenty‐six of 176 mutations could not be retrieved in related public databases and were considered to be novel. Among patients with ovarian cancer, 115 deleterious mutations were identified in 429 patients (48.6%) with significant enrichment for a family history of breast or ovarian cancer syndrome (P < .05). In the breast cancer subgroup, 31 deleterious mutations were identified in 261 patients. Besides BRCA1 (8; 25.8%) and BRCA2 (11; 35.5%), the most frequently occurring genes, an additional 12 deleterious mutations (38.7%) were found in seven other susceptibility genes. Higher mutation incidence (57.9%) was observed in subjects with histories of breast and ovarian cancer. Our results highlighted the genetic heterogeneity of HBOC and the efficiency of a multigene panel in carrying out risk assessment.

Clinical prognostic evaluation of immunocytes in different molecular subtypes of breast cancer

To retrospectively analyze the relationship between preoperative blood parameters and postoperative clinical outcomes in patients with different molecular subtypes of breast cancer (BC), a cohort of 601 patients with BC in the Third Affiliated Hospital, Sun Yat-sen University, was retrospectively reviewed. They were categorized into four subtypes according to the expression of ER, PR, HER-2, and KI-67%. White blood cell, neutrophil, lymphocyte, monocyte, eosinophil, basophil, and platelet counts, the neutrophil-to-lymphocyte ratio (NLR), the neutrophil-to-monocyte ratio (NMR), the lymphocyte-to-monocyte ratio (LMR), and the platelet-to-lymphocyte ratio (PLR) were recorded. Univariate and multivariate analyses were performed to identify the relationship between parameters and ratios and disease-free survival (DFS) and overall survival (OS). Luminal subtypes of BC had smaller tumor volume, better differentiation degree of invasive ductal carcinoma, less lymph node metastasis, and better clinical outcome than the HER-2 overexpression and triple-negative BC (TNBC) subtypes. In multivariate analysis, age and LMR were the independent prognostic factors of DFS in patients with luminal A (age, p = 0.005; LMR, P = 0.026); PLR in patients with luminal B (DFS; p = 0.032; OS, p= 0.012); LMR in patients with HER-2 overexpression (DFS; p = 0.008; OS, p = 0.017); and NLR for DFS (p = 0.014); and WBC for OS (p = 0.008) in patients with TNBC. LMR was the benign predictor of luminal A and HER-2 overexpression. PLR was the adverse predictor of luminal B. WBC and NLR were the adverse predictors of TNBC. Therefore, these peripheral blood parameters can play an important role in the diagnosis and treatment of patients with different molecular subtypes of BC.

Comprehensive mutation detection of BRCA1/2 genes reveals large genomic rearrangements contribute to hereditary breast and ovarian cancer in Chinese women

BACKGROUND

Mutated BRCA1/2 genes are associated with hereditary breast and ovarian cancer (HBOC). So far most of the identified BRCA1/2 pathogenic variants are single nucleotide variants (SNVs) or insertions/deletions (Indels). However, large genomic rearrangements (LGRs) such as copy number variants (CNVs) are also playing an important role in HBOC predisposition. Their frequency and spectrum have been well studied in western populations but remain largely unknown for Chinese population.

METHODS

Peripheral blood samples were collected from 218 unrelated familial breast and/or ovarian cancer (FBOC) patients living in Eastern China. PCR-based Sanger sequencing and panel-based next-generation sequencing (NGS) were performed to detect pathogenic SNVs and Indels in BRCA1/2 genes. For the patients lacking small pathogenic variants, multiplex ligation dependent probe amplification (MLPA) assay was conducted to screen for LGRs.

RESULTS

In total, we identified 44 samples (20.1%) carrying small pathogenic variants (26 in BRCA1 and 18 in BRCA2, respectively). Among the rest of 174 samples, five were found carrying novel deleterious LGRs in BRCA1 which are exon5-7dup (1 patient), exon13-14dup (2 patients), and exon1-22del (2 patients). No LGR was found in BRCA2. Overall, LGRs accounted for 16.1% (5/31) of BRCA1 pathogenic variants, and were detected in 2.3% (5/218) of all FBOC patients.

, CONCLUSIONS

LGR variants in BRCA1 gene play a significant role in Chinese HBOC patients. MLPA or other similar LGR-detecting methods should be recommended along with nucleotide sequencing as the initial screening approach for Chinese HBOC women.

Deleterious Mutations in DNA Repair Gene FANCC Exist in BRCA1/2-Negative Chinese Familial Breast and/or Ovarian Cancer Patients

Introduction: FANCC is reported as a novel susceptibility gene for breast cancer, however, its mutation remains unclear in Chinese population. We aimed to identify the germline mutations of FANCC in high-risk breast cancer patients in China. Methods: 255 BRCA1/2-negative Chinese familial breast and/or ovarian cancer (FBOC) patients were recruited for FANCC germline mutations screen. For whom 90 patients were detected by PCR-sequencing assay, and another 165 patients were detected by a 98-gene panel sequencing assay. The 98-gene panel sequencing assay was also used to screen other possible gene mutations for the patients with FANCC mutations detected by PCR-sequencing assay. Two hundred and fifty sporadic breast cancer (SBC) patients and 248 female non-cancer controls (FNCCs) were recruited for the genotyping analysis. Immunohistochemistry (IHC) analysis was used to evaluate the FANCC expression in patients with FANCC mutation. Results: We found one rare FANCC deleterious mutation (c.339G>A, p.W113X, 0.4%) and two novel non-synonymous variants (c.51G>C, p.Q17H, 0.4% and c.758C>A, p.A253E, 0.4%) in FBOC patients, whereas none of above mutations was identified in SBC patients or FNCCs. We also found that one novel synonymous variant (c.903A>G, p.A301A) existed in one FBOC patient. Additionally, two non-synonymous SNPs rs201407189 (c.973G>A, p.A325T) and rs1800367 (c.1345G>A, p.V449M), and two synonymous SNPs rs55719336 (c.816C>T, p.I272I) and rs79722116 (c.1407G>A, p.T469T) were identified in FBOC patients. Conclusion: FANCC deleterious mutations exist in Chinese FBOC patients and investigations on the penetrance and spectrum of FANCC mutations need to be further conducted.

BRCA1/2 mutation spectrum in Chinese early-onset breast cancer

Background

Breast cancer is the most commonly diagnosed cancer among women. Although many studies have reported the BRCA mutations among breast cancer patients, few studies have focused among Chinese early-onset breast cancer patients. The purpose of this study is to identify BRCA1 and BRCA2 mutation features and their clinical significance of early-onset Chinese breast cancer patients.

Methods

A total of 54 female patients diagnosed with breast cancer were enrolled in this study, of which 27 were younger than 40 (study group, mean age 32 years, range, 23–40 years) and 27 were older than 40 (control group, mean age 52 years, range, 41–68 years). Tumor FFPE samples were collected for somatic mutation test, while blood samples or normal tissue were used for germline mutation by both PGM and Miseq platform. All codon exons and functional introns for BRCA1/2 were covered. The clinical significance of mutation types was cross analyzed in several available database. The novel mutations were confirmed by sanger sequencing.

Results

In study group, 14.8% (4/27) and 3.7% (1/27) patients had deleterious BRCA1/2 germline and somatic mutations respectively. While in control group, only 3.7% (1/27) and 7.4% (2/27) had deleterious BRCA1/2 germline and somatic mutations respectively. BRCA1 germline mutation c.2623C>T and BRCA2 germline mutation c.5852G>A were found to be novel mutation sites and confirmed by sanger sequencing.

Conclusions

Our study found two novel BRCA1/2 mutation sites in early-onset breast cancer, and also showed that early-onset breast cancer patients are more likely to harbor germline mutations with deleterious and uncertain significance.

Risk prediction for breast Cancer in Han Chinese women based on a cause-specific Hazard model

Background

Considering the lack of efficient breast cancer prediction models suitable for general population screening in China. We aimed to develop a risk prediction model to identify high-risk populations, to help with primary prevention of breast cancer among Han Chinese women.

Methods

A cause-specific competing risk model was used to develop the Han Chinese Breast Cancer Prediction model. Data from the Shandong Case-Control Study (328 cases and 656 controls) and Taixing Prospective Cohort Study (13,176 participants) were used to develop and validate the model. The expected/observed (E/O) ratio and C-statistic were calculated to evaluate calibration and discriminative accuracy of the model, respectively.

Results

Compared with the reference level, the relative risks (RRs) for highest level of number of abortions, age at first live birth, history of benign breast disease, body mass index (BMI), family history of breast cancer, and life satisfaction scores were 6.3, 3.6, 4.3, 1.9, 3.3, 2.4, respectively. The model showed good calibration and discriminatory accuracy with an E/O ratio of 1.03 and C-statistic of 0.64.

Conclusions

We developed a risk prediction model including fertility status and relevant disease history, as well as other modifiable risk factors. The model demonstrated good calibration and discrimination ability.

Electronic supplementary material

The online version of this article (10.1186/s12885-019-5321-1) contains supplementary material, which is available to authorized users.

Detection of novel germline mutations in six breast cancer predisposition genes by targeted next-generation sequencing

In this study, a customized amplicon-based target sequencing panel was designed to enrich the whole exon regions of six genes associated with the risk of breast cancer. Targeted next-generation sequencing (NGS) was performed for 146 breast cancer patients (BC), 71 healthy women with a family history of breast cancer (high risk), and 55 healthy women without a family history of cancer (control). Sixteen possible disease-causing mutations on four genes were identified in 20 samples. The percentages of possible disease-causing mutation carriers in the BC group (8.9%) and in the high-risk group (8.5%) were higher than that in the control group (1.8%). The BRCA1 possible disease-causing mutation group had a higher prevalence in family history and triple-negative breast cancer, while the BRCA2 possible disease-causing mutation group was younger and more likely to develop axillary lymph node metastasis (P < 0.05). Among the 146 patients, 47 with a family history of breast cancer were also sequenced with another 14 moderate-risk genes. Three additional possible disease-causing mutations were found on PALB2, CHEK2, and PMS2 genes, respectively. The results demonstrate that the six-gene targeted NGS panel may provide an approach to assess the genetic risk of breast cancer and predict the clinical prognosis of breast cancer patients.

Clinicopathologic Factors Related to the Histological Tumor Grade of Breast Cancer in Western China: An Epidemiological Multicenter Study of 8619 Female Patients

BACKGROUND AND PURPOSE

Breast cancer is now recognized as a clinically heterogeneous disease with a wide spectrum of epidemiological and clinicopathologic features. We aimed to evaluate whether epidemiological and clinicopathologic features are associated with the histological tumor grade of breast carcinomas in Western China.

METHODS

We retrospectively collected data from the Western China Clinical Cooperation Group and assessed associations between clinicopathologic factors and histological tumor grade in 8619 female breast cancer patients. Patients were divided into two groups: Group I (tumor grade I/II) and Group II (tumor grade III). Univariable analysis and multivariable logistic regression models were used to analyze the relationships between clinicopathologic factors and tumor grade.

RESULTS

Patients presenting with positive axillary lymph nodes, large tumor size (>2 cm), lymphovascular invasion, hormone receptor negativity, human epidermal growth factor receptor 2 (HER-2) positivity, and triple negativity tended to have an increased risk of a high tumor grade. However, the number of pregnancies or births was inversely correlated with the risk of a high tumor grade. In addition, patients presenting with grade III tumors were more likely to receive aggressive treatment, such as adjuvant chemotherapy, anti-HER-2 therapy, and level III axillary lymph node dissection.

CONCLUSIONS

Our results suggested that several clinicopathologic factors were associated with high tumor grade of breast cancer patients in Western China.

Breast and ovarian cancer penetrance of BRCA1/2 mutations among Hong Kong women

Germline mutations in BRCA1 and BRCA2 (BRCA1/2) are associated with increased risk of breast and ovarian cancer. The penetrance of breast and ovarian cancer in BRCA1/2 mutation carriers has been well characterized in Caucasian but not in Asian. Two studies have investigated the breast cancer risk in Asian women with BRCA1/2 mutations, and no published estimates are available for ovarian cancer. Therefore, we estimated the age-specific cumulative risk of BRCA1/2-associated breast and ovarian cancer in Chinese women. From Jan 2007 to Nov 2015, the Hong Kong Hereditary Breast Cancer Family Registry identified 1635 families with hereditary breast-ovarian cancer. Among probands in these families, 66 had BRCA1 mutations, 84 had BRCA2 mutations, and 1,485 tested negative for BRCA1/2 mutations. Using the female first-degree relatives of these probands, we estimated the risk of breast and ovarian cancer using a modified marginal likelihood approach. Estimates of breast cancer penetrance by age 70 were 53.7% (95% CI 34.5-71.6%) for BRCA1 mutation carriers and 48.3% (95% CI 31.8-68.5%) for BRCA2. The estimated risk of ovarian cancer by age 70 was 21.5% and 7.3% for Chinese women carrying BRCA1 or BRCA2 mutation respectively. A meta-analysis of available studies in Asian women revealed pooled estimates of breast cancer risk by age 70 of 44.8% (95% CI 33-57.2%) and 40.7% (95% CI 31.3-50.9%) for BRCA1 and BRCA2 mutation carriers respectively. These data suggest that BRCA1/2-associated breast cancer risk for Chinese women is similar to that for Caucasian women, although BRCA1/2-associated ovarian cancer risks are lower for Chinese women.

Germline breast cancer susceptibility gene mutations and breast cancer outcomes

Background

It is unclear whether germline breast cancer susceptibility gene mutations affect breast cancer related outcomes. We wanted to evaluate mutation patterns in 20 breast cancer susceptibility genes and correlate the mutations with clinical characteristics to determine the effects of these germline mutations on breast cancer prognosis.

Methods

The study cohort included 480 ethnic Chinese individuals in Taiwan with at least one of the six clinical risk factors for hereditary breast cancer: family history of breast or ovarian cancer, young age of onset for breast cancer, bilateral breast cancer, triple negative breast cancer, both breast and ovarian cancer, and male breast cancer. PCR-enriched amplicon-sequencing on a next generation sequencing platform was used to determine the germline DNA sequences of all exons and exon-flanking regions of the 20 genes. Protein-truncating variants were identified as pathogenic.

Results

We detected a 13.5% carrier rate of pathogenic germline mutations, with BRCA2 being the most prevalent and the non-BRCA genes accounting for 38.5% of the mutation carriers. BRCA mutation carriers were more likely to be diagnosed of breast cancer with lymph node involvement (66.7% vs 42.6%; P = 0.011), and had significantly worse breast cancer specific outcomes. The 5-year disease-free survival was 73.3% for BRCA mutation carriers and 91.1% for non-carriers (hazard ratio for recurrence or death 2.42, 95% CI 1.29–4.53; P = 0.013). After adjusting for clinical prognostic factors, BRCA mutation remained an independent poor prognostic factor for cancer recurrence or death (adjusted hazard ratio 3.04, 95% CI 1.40–6.58; P = 0.005). Non-BRCA gene mutation carriers did not exhibit any significant difference in cancer characteristics or outcomes compared to those without detected mutations. Among the risk factors for hereditary breast cancer, the odds of detecting a germline mutation increased significantly with having bilateral breast cancer (adjusted odds ratio 3.27, 95% CI 1.64–6.51; P = 0.0008) or having more than one risk factor (odds ratio 2.07, 95% CI 1.22–3.51; P = 0.007).

Conclusions

Without prior knowledge of the mutation status, BRCA mutation carriers had more advanced breast cancer on initial diagnosis and worse cancer-related outcomes. Optimal approach to breast cancer treatment for BRCA mutation carriers warrants further investigation.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-4229-5) contains supplementary material, which is available to authorized users.

Rapid detection of BRCA1/2 recurrent mutations in Chinese breast and ovarian cancer patients with multiplex SNaPshot genotyping panels

BRCA1/2 mutations are significant risk factors for hereditary breast and ovarian cancer (HBOC), its mutation frequency in HBOC of Chinese ethnicity is around 9%, in which nearly half are recurrent mutations. In Hong Kong and China, genetic testing and counseling are not as common as in the West. To reduce the barrier of testing, a multiplex SNaPshot genotyping panel that targeted 25 Chinese BRCA1/2 mutation hotspots was developed, and its feasibility was evaluated in a local cohort of 441 breast and 155 ovarian cancer patients. For those who tested negative, they were then subjected to full-gene testing with next-generation sequencing (NGS). BRCA mutation prevalence in this cohort was 8.05% and the yield of the recurrent panel was 3.52%, identifying over 40% of the mutation carriers. Moreover, from 79 Chinese breast cancer cases recruited overseas, 2 recurrent mutations and one novel BRCA2 mutation were detected by the panel and NGS respectively. The developed genotyping panel showed to be an easy-to-perform and more affordable testing tool that can provide important contributions to improve the healthcare of Chinese women with cancer as well as family members that harbor high risk mutations for HBOC.

Evaluating genetic variants associated with breast cancer risk in high and moderate-penetrance genes in Asians

Over the past 20 years, high-penetrance pathogenic mutations in genes BRCA1, BRCA2, TP53, PTEN, STK11 and CDH1 and moderate-penetrance mutations in genes CHEK2, ATM, BRIP1, PALB2, RAD51C, RAD50 and NBN have been identified for breast cancer. In this study, we investigated whether there are additional variants in these 13 genes associated with breast cancer among women of Asian ancestry. We analyzed up to 654 single nucleotide polymorphisms (SNPs) from 6269 cases and 6624 controls of Asian descent included in the Breast Cancer Association Consortium (BCAC), and up to 236 SNPs from 5794 cases and 5529 controls included in the Shanghai Breast Cancer Genetics Study (SBCGS). We found three missense variants with minor allele frequency (MAF) <0.05: rs80358978 (Gly2508Ser), rs80359065 (Lys2729Asn) and rs11571653 (Met784Val) in the BRCA2 gene, showing statistically significant associations with breast cancer risk, with P-values of 1.2 × 10-4, 1.0 × 10-3 and 5.0 × 10-3, respectively. In addition, we found four low-frequency variants (rs8176085, rs799923, rs8176173 and rs8176258) in the BRCA1 gene, one common variant in the CHEK2 gene (rs9620817), and one common variant in the PALB2 gene (rs13330119) associated with breast cancer risk at P < 0.01. Our study identified several new risk variants in BRCA1, BRCA2, CHEK2, and PALB2 genes in relation to breast cancer risk in Asian women. These results provide further insights that, in addition to the high/moderate penetrance mutations, other low-penetrance variants in these genes may also contribute to breast cancer risk.

PALB2 mutation in a woman with bilateral breast cancer: A case report

Partner and localizer of breast cancer 2 (PALB2) was identified as a moderate-risk gene of breast and pancreas cancer. The present authors previously reported that no PALB2 germline mutations with a deleterious frameshift or stop codons were identified in 155 Japanese patients with breast and/or ovarian cancer who were estimated to be at risk of hereditary cancer, according to the National Comprehensive Cancer Network (NCCN) criteria. In the present study, one patient with a deleterious mutation of PALB2 (c. 2834+2 T>C) has been identified from a study of an additional 128 cases. Therefore, the prevalence of PALB2 among Japanese patients is now estimated to be 0.35% (1/283). The proband was a 63-year-old woman with bilateral breast cancer, although she had experienced no other cancers. The proband had two elder sisters, the eldest of whom died from pancreatic cancer at 60 years of age. The proband's 40-year-old daughter was affected, but did not show any malignancies. There are only a few reports concerning PALB2 mutations in Japan. To the best of our knowledge, this is the first case study to reveal the significance of DNA-repair genes in the development of malignancies in Japanese patients with breast cancer.

Human serum albumin-mediated apoptin delivery suppresses breast cancer cell growth in vitro and in vivo

Gene therapy is one of the most promising potential therapeutic strategies for many types of cancer. Cell apoptosis is an active, programmed physiological process of the body, and its disruption has been closely associated with the occurrence of tumor development. Apoptin is known to induce tumor cell apoptosis. In the present study, the MCF-7 breast cancer cell line was transfected with a human serum albumin (HSA) and apoptin expressing plasmid [HSA-polyethylenimine (PEI)-pcDNA-Apoptin]. Reverse transcription-quantitative polymerase chain reaction and western blotting were performed to detect the expression of apoptin in the transfected MCF-7 cells, while MTT assays and flow cytometry were conducted to detect cell viability and apoptosis. Furthermore, hematoxylin and eosin staining was used to observe the morphology of xenografts from mice injected with MCF-7 cells. It was demonstrated that the HSA-PEI-pcDNA-Apoptin expression plasmid resulted in the upregulation of apoptin in MCF-7 cells, and efficiently suppressed breast tumor growth in vivo. These findings indicated that the use of HSA as an apoptin expression vector has potential therapeutic benefits for cancer and confirms the requirement for the further evaluation of apoptin in clinical trials.

Genetic evaluation and testing for hereditary forms of cancer in the era of next-generation sequencing

The introduction of next-generation sequencing (NGS) technology in testing for hereditary cancer susceptibility allows testing of multiple cancer susceptibility genes simultaneously. While there are many potential benefits to utilizing this technology in the hereditary cancer clinic, including efficiency of time and cost, there are also important limitations that must be considered. The best panel for the given clinical situation should be selected to minimize the number of variants of unknown significance. The inclusion in panels of low penetrance or newly identified genes without specific actionability can be problematic for interpretation. Genetic counselors are an essential part of the hereditary cancer risk assessment team, helping the medical team select the most appropriate test and interpret the often complex results. Genetic counselors obtain an extended family history, counsel patients on the available tests and the potential implications of results for themselves and their family members (pre-test counseling), explain to patients the implications of the test results (post-test counseling), and assist in testing family members at risk.

Novel germline mutations and unclassified variants of BRCA1 and BRCA2 genes in Chinese women with familial breast/ovarian cancer

BACKGROUND

Germline mutations in the BRCA1 and BRCA2 genes greatly increase a woman's risk of developing breast and/or ovarian cancer. The prevalence and distribution of such mutations differ across races/ethnicities. Several studies have investigated Chinese women with high-risk breast cancer, but the full spectrum of the mutations in these two genes remains unclear.

METHODS

In this study, 133 unrelated Chinese women with familial breast/ovarian cancer living in Zhejiang, eastern China, were enrolled between the years 2008 and 2014. The complete coding regions and exon-intron boundaries of BRCA1 and BRCA2 were screened by PCR-sequencing assay. Haplotype analysis was performed to confirm BRCA1 and BRCA2 founder mutations. In silico predictions were performed to identify the non-synonymous amino acid changes that were likely to disrupt the functions of BRCA1 and BRCA2.

RESULTS

A total of 23 deleterious mutations were detected in the two genes in 31 familial breast/ovarian cancer patients with a total mutation frequency of 23.3% (31/133). The highest frequency of 50.0% (8/16) was found in breast cancer patients with a history of ovarian cancer. The frequencies of BRCA1 and BRCA2 mutations were 13.5 % (18/133) and 9.8% (13/133), respectively. We identified five novel deleterious mutations (c.3295delC, c.3780_3781delAG, c.4063_4066delAATC, c.5161 > T and c.5173insA) in BRCA1 and seven (c.1-40delGA, c.4487delC, c.469_473delAAGTC, c.5495delC, c.6141T > A, c.6359C > G and c.7588C > T) in BRCA2, which accounted for 52.2% (12/23) of the total mutations. Six recurrent mutations were found, including four (c.3780_3781delAG, c.5154G > A, c.5468-1del8 and c.5470_5477del8) in BRCA1 and two (c.3109C > T and c.5682C > G) in BRCA2. Two recurrent BRCA1 mutations (c.5154G > A and c.5468-1del8) were identified as putative founder mutations. We also found 11 unclassified variants, and nine of these are novel. The possibility was that each of the non-synonymous amino acid changes would disrupt the function of BRCA1 and BRCA2 varied according to the different algorithms used.

CONCLUSIONS

BRCA1 and BRCA2 mutations accounted for a considerable proportion of hereditary breast/ovarian cancer patients from eastern China and the spectrum of the mutations of these two genes exhibited some unique features. The two BRCA1 putative founder mutations may provide a cost-effective option to screen Chinese population, while founder effects of the two mutations should be investigated in a lager sample size of patients.

Identification of germline alterations in breast cancer predisposition genes among Malaysian breast cancer patients using panel testing

Although an association between protein-truncating variants and breast cancer risk has been established for 11 genes, only alterations in BRCA1, BRCA2, TP53 and PALB2 have been reported in Asian populations. Given that the age of onset of breast cancer is lower in Asians, it is estimated that inherited predisposition to breast cancer may be more significant. To determine the potential utility of panel testing, we investigated the prevalence of germline alterations in 11 established and 4 likely breast cancer genes in a cross-sectional hospital-based cohort of 108 moderate to high-risk breast cancer patients using targeted next generation sequencing. Twenty patients (19%) were identified to carry deleterious mutations, of whom 13 (12%) were in the BRCA1 or BRCA2, 6 (6%) were in five other known breast cancer predisposition genes and 1 patient had a mutation in both BRCA2 and BARD1. Our study shows that BRCA1 and BRCA2 account for the majority of genetic predisposition to breast cancer in our cohort of Asian women. Although mutations in other known breast cancer genes are found, the functional significance and breast cancer risk have not yet been determined, thus limiting the clinical utility of panel testing in Asian populations.

Analysis of PALB2 mutations in 155 Japanese patients with breast and/or ovarian cancer

BACKGROUND

PALB2 (Partner and Localizer of BRCA2) was identified as a moderate-risk gene in breast and pancreatic cancers. Recently, it was reported that PALB2 carriers have a high risk of developing breast cancer, with the cumulative risk of 34 % by the age of 70.

PATIENTS AND METHODS

Peripheral blood samples from 155 patients at risk for hereditary breast and/or ovarian cancer were tested for BRCA1/2 and PALB2 by targeted sequencing using a next-generation sequencer. Of these 155, 146 met NCCN criteria and the remaining 9 did not.

RESULTS

BRCA1/2 analysis was performed on 155 patients, for whom the results were reported previously (Hirotsu Y et al. Mol Genet Genomic Med, doi:10.1002/mgg3.157, 2015). Eleven patients were identified to have deleterious BRCA mutations (Hirotsu Y et al. Mol Genet Genomic Med, doi:10.1002/mgg3.157, 2015). However, none of the 155 patients were found to have deleterious PALB2 germline mutations. Missense mutations [variants of uncertain significance (VUS)] of PALB2 were found in 12 cases. In silico analyses by SIFT (Sorting Intolerant Form Tolerant) and PolyPhen2 (Polymorphism Phenotyping version 2) indicated that 2 of 12 VUS were deleterious and probably damaging.

CONCLUSIONS

This is the first report on PALB2 mutations in Japan, revealing two missense mutations as "deleterious and probably damaging" by in silico analyses, but no PALB2 premature truncation mutations were identified. The sample size is relatively small and a larger cohort study is needed in Japan.

MicroRNA-802 suppresses breast cancer proliferation through downregulation of FoxM1

An increasing number of studies have shown that microRNAs (miRNAs) are critical in tumor cell proliferation, as they modulate key gene transcripts. In the present study, the expression and roles of miRNA (miR)‑802 were analyzed by quantitative polymerase chain reaction in breast cancer cells. The results showed that expression levels of miR‑802 were significantly reduced in breast cancer tissues and cells compared with those of normal tissue and normal breast epithelial cells. In vitro and in vivo experiments demonstrated that miR‑802 overexpression inhibited cell proliferation in MCF‑7 breast cancer cells and tumor growth in nude mice, respectively. Furthermore, mechanistic investigation with western blotting and luciferase reporter assays revealed that miR‑802 overexpression downregulated protein expression levels of Forkhead box protein M1 (FoxM1). Therefore, the results of the present study provided evidence for a previously undetermined miR‑802/FoxM1 molecular network, which was involved in the regulation of breast cancer cell proliferation.

The clinicopathological significance of microRNA-155 in breast cancer: a meta-analysis

OBJECTIVE

Previous studies demonstrated that the associations between expression level of microRNA-155 (miR-155) and clinicopathological significance of breast cancer remained inconsistent. Therefore, we performed a meta-analysis based on eligible studies to summarize the possible associations.

METHODS

We identified eligible studies published up to May 2014 by a comprehensive search of PubMed, EMBASE, CNKI, and VIP databases. The analysis was performed with RevMan. 5.0 software.

RESULTS

A total of 15 studies were included. The results of meta-analysis showed that miR-155 was positively correlated with breast cancer with standardized mean difference (SMD) = 1.22. Elevated miR-155 was found in Her-2 positive or lymph node metastasis positive, or p53 mutant type breast cancer. But the result showed to be insignificant in TNM comparison. With respect to estrogen receptor alpha (ER) and progesterone receptor (PR) status, both of them showed significant associations with SMD = -1.2 and -1.85, respectively.

CONCLUSION

MiR-155 detection might have a diagnostic value in breast cancer patients. It might be used as an auxiliary biomarker for different clinicopathological breast cancer.

Distribution of BRCA1 and BRCA2 Mutations in Asian Patients with Breast Cancer

Breast cancer is the most prevalent cancer in Asian females, and the incidence of breast cancer has been increasing in Asia. Because Asian patients develop breast cancer at a younger age than their Caucasian counterparts, the contributions of BRCA1 and BRCA2 (BRCA1/2) mutations in Asians are expected to be different than in Caucasians. The prevalence of BRCA1/2 mutations in the Asian population varies among countries and studies. Most Asian studies have reported more frequent mutations in BRCA2 than in BRCA1, with the exception of studies from India and Pakistan. In addition, the contribution of large genomic rearrangements of BRCA1/2 genes is relatively small in Asian populations in comparison to other ethnic populations. Various statistical models for the prediction of BRCA1/2 mutations have underestimated the risk of having these genetic mutations in Asians, especially in predicting BRCA2 gene mutation. Until recently, BRCA1/2 mutation analyses in Asia were mostly conducted by independent single institutions with different patient selection criteria and using various genotyping methods. However, a couple of Asian groups have initiated nationwide studies collecting BRCA1/2 mutational data. These national collaborative studies will help a comprehensive understanding of the prevalence of BRCA1/2 mutations in the Asian population.

Leptin promotes the proliferation and migration of human breast cancer through the extracellular-signal regulated kinase pathway

Obesity has been associated with an increased risk of postmenopausal breast cancer, which may be due to the expression of leptin. The aim of this study was to determine the role of leptin in the growth of breast cancer cells in nude mice, the proliferation and migration of MCF-7 human breast cancer cells and its downstream signaling pathway. The xenograft mouse model was elicited by injecting MCF-7 human breast cancer cells into the left back axilla and the tumor size was measured every other day. Leptin injected subcutaneously around the tumor site led to an increase in the size and weight of the tumor, whereas the leptin antagonist (LA) significantly inhibited the size and weight of the tumor. Leptin promoted the proliferation and migration of MCF-7 cells and LA inhibited it. The effects of leptin on increasing the size and weight of the tumor in the nude mice and the proliferation and migration of MCF-7 human breast cancer cells were eradicated by pretreatment with LA, the extracellular-signal regulated kinase (ERK) inhibitor PD98059. In the xenograft mouse model the leptin level was increased and leptin increased the phosphorylation of ERK in the MCF-7 cells, whereas LA significantly reduced the phosphorylation of ERK. These results indicated that leptin promotes the growth of breast cancer in the nude mice and increases the proliferation and migration of MCF-7 human breast cancer cells via the ERK pathway.