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

The deubiquitinating enzyme USP4 regulates BRCA1 stability and function

BRCA1 plays a suppressive role in breast tumorigenesis. Ubiquitin-dependent degradation is a common mechanism that regulates BRCA1 protein stability, and several ubiquitin ligases involved have been identified. However, the deubiquitinating enzyme for BRCA1 remains less defined. Here, we report that the deubiquitinase USP4 interacts with, deubiquitinates and stabilizes BRCA1, maintaining the protein level of BRCA1. USP4 knockdown results in a decreased BRCA1 protein level, impairment in homologous recombination mediated double-stranded break repair, and increased genome instability, and confers resistance to DNA damage-inducing agents and PARP inhibitors. Ectopic expression of USP4 stabilizes BRCA1 and reverse the effects caused by USP4 knockdown. Moreover, USP4 is low expressed in human breast cancer tissues and its low expression correlates with poorer survival of patients. Furthermore, we identified several loss-of-function mutations of USP4 in human gynecological cancers, the catalytic activity of which or their interaction with BRCA1 is disrupted. Together, we reveal that USP4 is a deubiquitinase for BRCA1. USP4 positively regulates the stability and function of BRCA1 through de-ubiquitination, and plays important role in the suppression of breast cancer.

High Frequency of BRCA2 c.5576_5579del Carriers in Kakogawa, Japan

Background/Aim

Certain germline pathogenic variants (PVs), known as founder mutations, have been frequently observed in specific regions and ethnic groups. In Japan, several pathogenic variants of BRCA1/2 have been identified as founder mutations, with their distribution varying across different regions. This retrospective study aimed to further investigate the detailed distribution and correlation between genotype and clinical features among breast cancer patients.

Patients and Methods

This study was conducted at Kobe University Hospital and three collaborating institutions. It included breast cancer patients who underwent BRCA1/2 genetic testing between July 1, 2018, and March 31, 2021, and were found to have germline PVs. Clinical characteristics and breast cancer subtypes were compared between carriers of BRCA2 c.5576_5579del and those with other PVs. Additionally, the detection rate of BRCA2 c.5576_5579del was compared with that observed in a previous report.

Results

A total of 38 breast cancer patients were included; PVs in BRCA1 and BRCA2 were detected in 12 and 26 patients, respectively, 12 of whom were BRCA2 c.5576_5579del carriers. BRCA2 c.5576_5579del carriers were more likely to develop triple negative breast cancers among all BRCA2 PV carriers. BRCA2 c.5576_5579del accounted for 30.8% of the PVs detected, with a particularly high frequency of 72.7% at Kakogawa Central City Hospital.

Conclusion

BRCA2 c.5576_5579del was detected with a particularly high frequency in Hyogo Prefecture, especially in Kakogawa city. In the future, a survey of the distribution of the BRCA2 c.5576_5579del carriers may provide more clarity regarding their localization.

Genetic landscape of breast cancer subtypes following radiation therapy: insights from comprehensive profiling

Background

In breast cancer, in the era of precision cancer therapy, different patterns of genetic mutations dictate different treatments options. However, it is not clear whether the genetic profiling of breast cancer patients undergoing breast-conserving surgery is related to the adverse reactions caused by radiotherapy.

Methods

We collected formalin-fixed paraffin-embedded (FFPE) tumor tissue samples from 54 breast cancer patients treated with radiation after breast-conserving surgery and identified comprehensive molecular information in hundreds of cancer-associated genes by FoundationOne CDx (F1CDx), a next-generation sequencing (NGS)-based assay.

Results

Among our cohort of 54 breast cancer patients, we found high-frequency mutations in cancer-related genes such as TP53 (56%), RAD21 (39%), PIK3CA (35%), ERBB2 (24%), and MYC (22%). Strikingly, we detected that the WNT pathway appears to be a signaling pathway with specific high-frequency mutations in the HER2 subtype. We also compared the mutation frequencies of the two groups of patients with and without cutaneous radiation injury (CRI) after radiotherapy and found that the mutation frequencies of two genes, FGFR1 and KLHL6, were significantly higher in patients with CRI : No subgroup than in those with CRI : Yes.

Conclusion

Different breast cancer subtypes have their own type-specific mutation patterns. FGFR1 and KLHL6 mutations are protective factors for radiation-induced skin toxicity in breast cancer patients.

A Phase II Study of Neoadjuvant PLD/Cyclophosphamide and Sequential nab-Paclitaxel Plus Dual HER2 Blockade in HER2-Positive Breast Cancer

BACKGROUND

Neoadjuvant trastuzumab/pertuzumab (HP) plus chemotherapy for HER2-positive breast cancer (BC) achieved promising efficacy. The additional cardiotoxicity still existed. Brecan study evaluated the efficacy and safety of neoadjuvant pegylated liposomal doxorubicin (PLD)/cyclophosphamide and sequential nab-paclitaxel based on HP (PLD/C/HP-nabP/HP).

PATIENTS AND METHODS

Brecan was a single-arm phase II study. Eligible patients with stages IIA-IIIC HER2-positive BC received 4 cycles of PLD, cyclophosphamide, and HP, followed by 4 cycles of nab-paclitaxel and HP. Definitive surgery was scheduled after 21 days for patients completing treatment or experiencing intolerable toxicity. The primary endpoint was the pathological complete response (pCR).

RESULTS

Between January 2020 and December 2021, 96 patients were enrolled. Ninety-five (99.0%) patients received 8 cycles of neoadjuvant therapy and all underwent surgery with 45 (46.9%) breast-conserving surgery and 51 (53.1%) mastectomy. The pCR was 80.2% (95%CI, 71.2%-87.0%). Four (4.2%) experienced left ventricular insufficiency with an absolute decline in LVEF (43%-49%). No congestive heart failure and ≥grade 3 cardiac toxicity occurred. The objective response rate was 85.4% (95%CI, 77.0%-91.1%), including 57 (59.4%) complete responses and 25 (26.0%) partial responses. The disease control rate was 99.0% (95%CI, 94.3%-99.8%). For overall safety, ≥grade 3 AEs occurred in 30 (31.3%) and mainly included neutropenia (30.2%) and asthenia (8.3%). No treatment-related deaths occurred. Notably, age of >30 (P = .01; OR = 5.086; 95%CI, 1.44-17.965) and HER2 IHC 3+ (P = .02; OR = 4.398; 95%CI, 1.286-15.002) were independent predictors for superior pCR (ClinicalTrials.gov Identifier NCT05346107).

CONCLUSION

Brecan study demonstrated the encouraging safety and efficacy of neoadjuvant PLD/C/HP-nabP/HP, suggesting a potential therapeutic option in HER2-positive BC.

Prevalence of BRCA1, BRCA2, and PALB2 genomic alterations among 924 Taiwanese breast cancer assays with tumor-only targeted sequencing: extended data analysis from the VGH-TAYLOR study

BACKGROUND

The homologous recombination (HR) repair pathway for DNA damage, particularly the BRCA1 and BRCA2 genes, has become a target for cancer therapy, with poly ADP-ribose polymerase (PARP) inhibitors showing significant outcomes in treating germline BRCA1/2 (gBRCA1/2) mutated breast cancer. Recent studies suggest that some patients with somatic BRCA1/2 (sBRCA1/2) mutation or mutations in HR-related genes other than BRCA1/2 may benefit from PARP inhibitors as well, particularly those with PALB2 mutations. The current analysis aims to evaluate the prevalence of genetic alterations specific to BRCA1, BRCA2, and PALB2 in a large cohort of Taiwanese breast cancer patients through tumor-targeted sequencing.

METHODS

A total of 924 consecutive assays from 879 Taiwanese breast cancer patients underwent tumor-targeted sequencing (Thermo Fisher Oncomine Comprehensive Assay v3). We evaluated BRCA1, BRCA2, and PALB2 mutational profiles, with variants annotated and curated by the ClinVAR, the Oncomine™ Knowledgebase Reporter, and the OncoKB™. We also conducted reflex germline testing using either whole exome sequencing (WES) or whole genome sequencing (WGS), which is ongoing.

RESULTS

Among the 879 patients analyzed (924 assays), 130 had positive mutations in BRCA1 (3.1%), BRCA2 (8.6%), and PALB2 (5.2%), with a total of 14.8% having genetic alterations. Co-occurrence was noted between BRCA1/BRCA2, BRCA1/PALB2, and BRCA2/PALB2 mutations. In BRCA1-mutated samples, only p.K654fs was observed in three patients, while other variants were observed no more than twice. For BRCA2, p.N372H was the most common (26 patients), followed by p.S2186fs, p.V2466A, and p.X159_splice (5 times each). For PALB2, p.I887fs was the most common mutation (30 patients). This study identified 176 amino acid changes; 60.2% (106) were not documented in either ClinVAR or the Oncomine™ Knowledgebase Reporter. Using the OncoKB™ for annotation, 171 (97.2%) were found to have clinical implications. For the result of reflex germline testing, three variants (BRCA1 c.1969_1970del, BRCA1 c.3629_3630del, BRCA2 c.8755-1G > C) were annotated as Pathogenic/Likely pathogenic (P/LP) variants by ClinVar and as likely loss-of-function or likely oncogenic by OncoKB; while one variant (PALB2 c.448C > T) was not found in ClinVar but was annotated as likely loss-of-function or likely oncogenic by OncoKB.

CONCLUSION

Our study depicted the mutational patterns of BRCA1, BRCA2, and PALB2 in Taiwanese breast cancer patients through tumor-only sequencing. This highlights the growing importance of BRCA1/2 and PALB2 alterations in breast cancer susceptibility risk and the treatment of index patients. We also emphasized the need to meticulously annotate variants in cancer-driver genes as well as actionable mutations across multiple databases.

Application of Biosensors in Detecting Breast Cancer Metastasis

Breast cancer has garnered global attention due to its high incidence worldwide, and even more noteworthy is that approximately 90% deaths due to breast cancer are attributed to cancer metastasis. Therefore, the early diagnosis of breast cancer metastasis holds significant importance for reducing mortality outcomes. Biosensors play a crucial role in the early detection of metastatic breast cancer due to their advantages, such as ease of use, portability, and real-time analysis capabilities. This review primarily described various types of sensors for detecting breast cancer metastasis based on biomarkers and cell characteristics, including electrochemical, optical, and microfluidic chips. We offered detailed descriptions of the performance of these various biosensors and made comparisons between them. Furthermore, we described the pathology of breast cancer and summarized commonly used biomarkers for metastatic breast cancer. Finally, we discussed the advantages of current-stage biosensors and the challenges that need to be addressed, as well as prospects for their future development.

Ethnic-specificity, evolution origin and deleteriousness of Asian BRCA variation revealed by over 7500 BRCA variants derived from Asian population

Pathogenic variation in BRCA1 and BRCA2 (BRCA) causes high risk of breast and ovarian cancer, and BRCA variation data are important markers for BRCA-related clinical cancer applications. However, comprehensive BRCA variation data are lacking from the Asian population despite its large population size, heterogenous genetic background and diversified living environment across the Asia continent. We performed a systematic study on BRCA variation in Asian population including extensive data mining, standardization, annotation and characterization. We identified 7587 BRCA variants from 685 592 Asian individuals in 40 Asia countries and regions, including 1762 clinically actionable pathogenic variants and 4915 functionally unknown variants (https://genemutation.fhs.um.edu.mo/Asian-BRCA/). We observed the highly ethnic-specific nature of Asian BRCA variants between Asian and non-Asian populations and within Asian populations, highlighting that the current European descendant population-based BRCA data is inadequate to reflect BRCA variation in the Asian population. We also provided archeological evidence for the evolutionary origin and arising time of Asian BRCA variation. We further provided structural-based evidence for the deleterious variants enriched within the functionally unknown Asian BRCA variants. The data from our study provide a current view of BRCA variation in the Asian population and a rich resource to guide clinical applications of BRCA-related cancer for the Asian population.

Germline variants associated with breast cancer in Khakass women of North Asia

INTRODUCTION

Variants in the BRCA1/2 genes are responsible for familial breast cancer. Numerous studies showed a different spectrum of BRCA variants among breast cancer patients of different Ethnicity origin. In the available literature, no previous research has focused on breast cancer-associated variants among the Khakass people (the indigenous people of the Russian Federation).

METHODS

Twenty-six Khakass breast cancer patients were enrolled in the study. Genomic DNA was isolated from blood samples and used to prepare libraries using a Hereditary Cancer Solution kit. Next-generation sequencing (NGS) was performed using the MiSeq System (Illumina, USA).

RESULTS

In our study, 12% of patients (3/26) carried a single pathogenic variant; 54% of patients (14/26) carried variants of uncertain significance (VUS) or conflicting variants; and 35% of patients (9/26) did not carry any clinically significant variants. Germline pathogenic variant in the ATM gene (rs780619951, NC_000011.10:g.108259022C > T) was identified in two unrelated patients with a family history of cancer (7.6%, 2/26). The pathogenic truncating variant in the ATM gene (p. R805* or c.2413C > T) leads to the nonfunctional version of the protein. This variant has been earlier reported in individuals with a family history of breast cancer.

CONCLUSIONS

Our pilot study describes the germline variant in the ATM gene associated with breast cancer in Khakass women of North Asia.

Efficacy and safety of treatment regimens for patients with metastatic, locally advanced, or recurrent breast cancer carrying BRCA1/BRCA2 pathogenic variants: A network meta-analysis

Objective

Patients with breast cancer carrying BRCA1 and BRCA2 genetic alterations show poor prognoses. However, the efficacy of pharmacotherapies for patients with advanced breast cancer carrying BRCA1/2 pathogenic variants remains unclear. This study aimed to conduct a network meta-analysis to assess the efficacy and safety of various pharmacotherapies for patients with metastatic, locally advanced, or recurrent breast cancer carrying BRCA1/BRCA2 pathogenic variants.

Methods

A literature search was conducted using Embase, PubMed, and Cochrane Library (CENTRAL), from inception to 11^th May 2022. The references of included articles were screened to identify relevant literature. This network meta-analysis included patients with metastatic locally advanced or recurrent breast cancer who received pharmacotherapy and carried deleterious variants of BRCA1/2. The Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines were followed for conducting and reporting this systematic meta-analysis. The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) method was employed to evaluate evidential certainty. Frequentist random-effect model was applied. Results of objective response rate (ORR), progression-free survival (PFS), overall survival (OS), and rates of any-grade adverse events were presented.

Results

Nine randomized controlled trials were obtained comprising six treatment regimens, including 1912 patients with pathogenic variants of BRCA1 and BRCA2. The orchestration of PARP inhibitors with platinum-based chemotherapy was found to be the most effective with a pooled odds ratio (OR) of 3.52 (95% CI 2.14, 5.78) for ORR; 1.53 (1.34,1.76), 3.05 (1.79, 5.19), and 5.80 (1.42, 23.77) for 3-, 12-, and 24-month PFS, respectively, and 1.04 (1.00, 1.07), 1.76 (1.25, 2.49) and 2.31 (1.41, 3.77) for 3-, 12-, and 36-month OS, respectively compared to those receiving non-platinum-based chemotherapy. However, it posed an elevated risk of some adverse events. Platinum-based chemotherapy alone or PARP inhibitors markedly improved ORR, PFS, and OS compared to non-platinum-based chemotherapy. Interestingly, platinum-based chemotherapy surpassed PARP inhibitors in terms of efficacy. Evidence on programmed death-ligand 1(PD-L1) inhibitors and sacituzumab govitecan (SG) suggested low quality and insignificant results.

Conclusions

Among all treatment regimens, PARP inhibitors with platinum exhibited the best efficacy, although with a trade-off of elevated risk of some types of adverse events. Future research on direct comparisons between different treatment regimens specifically targeting patients with breast cancer carrying BRCA1/2 pathogenic variants with a pre-specified adequate sample size is warranted.

C-CAT: The National Datacenter for Cancer Genomic Medicine in Japan

SUMMARY

Since June 2019, under the umbrella of the national health insurance system, Japan has started cancer genomic medicine (CGM) with comprehensive genomic profiling (CGP) tests. The Ministry of Health, Labour and Welfare (MHLW) of Japan constructed a network of CGM hospitals (a total of 233 institutes as of July 1, 2022) and established the Center for Cancer Genomics and Advanced Therapeutics (C-CAT), the national datacenter for CGM. Clinical information and genomic data from the CGP tests are securely transferred to C-CAT, which then generates "C-CAT Findings" reports containing information of clinical annotation and matched clinical trials based on the CGP data. As of June 30, 2022, a total of 36,340 datapoints of clinical/genomic information are aggregated in C-CAT, and the number is expected to increase swiftly. The data are now open for sharing with not only the CGM hospitals but also other academic institutions and industries.

Application of Multigene Panels Testing for Hereditary Cancer Syndromes

BACKGROUND

Approximately 5-10% of all cancers are associated with hereditary cancer predisposition syndromes (HCPS). Early identification of HCPS is facilitated by widespread use of next-generation sequencing (NGS) and brings significant benefits to both the patient and their relatives. This study aims to evaluate the landscape of genetic variants in patients with personal and/or family history of cancer using NGS-based multigene panel testing.

MATERIALS AND METHODS

The study cohort included 1117 probands from Russia: 1060 (94.9%) patients with clinical signs of HCPS and 57 (5.1%) healthy individuals with family history of cancer. NGS analysis of 76 HCPS genes was performed using a custom Roche NimbleGen enrichment panel.

RESULTS

Pathogenic/likely pathogenic variants were identified in 378 of 1117 individuals (33.8%). The predominant number (59.8%) of genetic variants was identified in BRCA1/BRCA2 genes. CHEK2 was the second most commonly altered gene with a total of 28 (7.4%) variants, and 124 (32.8%) genetic variants were found in other 35 cancer-associated genes with variable penetrance.

CONCLUSIONS

Multigene panel testing allows for a differential diagnosis and identification of high-risk group for oncological diseases. Our results demonstrate that inclusion of non-coding gene regions into HCPS gene panels is highly important for the identification of rare spliceogenic variants with high penetrance.

Germline landscape of BRCAs by 7-site collaborations as a BRCA consortium in Turkey

BRCA1/2 mutations play a significant role in cancer pathogenesis and predisposition particularly in breast, ovarian and prostate cancers. Thus, germline analysis of BRCA1 and BRCA2 is essential for clinical management strategies aiming at the identification of recurrent and novel mutations that could be used as a first screening approach. We analyzed germline variants of BRCA1/2 genes for 2168 individuals who had cancer diagnosis or high risk assessment due to BRCAs related cancers, referred to 10 health care centers distributed across 7 regions covering the Turkish landscape. Overall, 68 and 157 distinct mutations were identified in BRCA1 and BRCA2, respectively. Twenty-two novel variants were reported from both genes while BRCA2 showed higher mutational heterogeneity. We herein report the collective data as BRCA Turkish consortium that confirm the molecular heterogeneity in BRCAs among Turkish population, and also as the first study presenting the both geographical, demographical and gene based landscape of all recurrent and novel mutations which some might be a founder effect in comparison to global databases. This wider perspective leads to the most accurate variant interpretations which pave the way for the more precise and efficient management affecting the clinical and molecular aspects.

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A similar percentage of clinically unaffected individuals were also identified with potentially pathogenic variants.

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Based on the geographic examinations, Eastern Anatolian and the Mediterranean region had the lowest positivity rates.

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The Southeastern Anatolian region showed the lowest density of both patients and clinically relevant genetic changes.

The relationship between tobacco and breast cancer incidence: A systematic review and meta-analysis of observational studies

Background

The effect of tobacco on breast cancer (BC) is controversial. The purpose of this study was to investigate the relationship between tobacco and BC.

Methods

A search was conducted in PubMed, EBSCO, Web of Science and Cochrane Library databases before February 2022. The adjusted odd ratio (OR) and corresponding 95% confidence interval (CI) were used to examine the relationship between active or passive smoking and BC risk.

Results

A total of 77 articles composed of 2,326,987 participants were included for this meta-analysis. Active (OR=1.15, 95% CI=1.11-1.20, p<0.001) and passive (OR=1.17, 95% CI=1.09-1.24, p<0.001) smoking increased the risk of BC in the female population, especially premenopausal BC (active smoking: OR=1.24, p<0.001; passive smoking: OR=1.29, p<0.001), but had no effect on postmenopausal BC (active smoking: OR=1.03, p=0.314; passive smoking: OR=1.13, p=0.218). Active smoking increased the risk of estrogen receptor-positive (ER+) BC risk (OR=1.13, p<0.001), but had no effect on estrogen receptor-negative (ER-) BC (OR=1.08, p=0.155). The risk of BC was positively associated with the duration and intensity of smoking, negatively associated with the duration of smoking cessation. Active smoking increased the risk of BC in the multiparous population (OR=1.13, p<0.001), but had no effect on the nulliparous population (OR=1.05, p=0.432), and smoking before the first birth (OR=1.22, 95% CI=1.17-1.27) had a greater impact on the risk of BC than smoking after the first birth (OR=1.08, 95% CI=1.04-1.12).

Conclusion

Smoking (active and passive) increased the risk of BC in women. The effect of smoking on BC was influenced by smoking-related factors (duration, intensity, years of quitting), population-related factors (fertility status), and BC subtypes.

Systematic Review Registration

identifier CRD42022322699.

Effects of the Methylation Levels for the Breast Cancer Associated Genes BCSG1 and BRCA1 on Cellular Proliferation and Migration

Objective: The aim of this study was to determine whether the methylation patterns of the breast cancer-specific gene 1 (BCSG1) and the breast cancer susceptibility gene 1 (BRCA1) can be used as biomarkers for predicting the occurrence and development of breast cancer. Methods: Methylation-specific polymerase chain reaction (PCR) was used to detect the methylation status of the BCSG1 and BRCA1 genes in ductal infiltrating carcinomas of the breast; carcinoma in situ of the breast; fibroadenoma of the breast and adjacent normal tissues. Quantitative real-time PCR and immunohistochemistry were used to detect the expression levels of BCSG1 and BRCA1. The BCSG1 and BRCA1 genes were knocked down by siRNA to study their effect of BCSG1 and BRCA1 on the behaviour of breast cancer cell lines. Results: The BCSG1 gene was hypomethylated in breast cancer tissues, and its mRNA as well as its protein levels showed elevated expression compared to normal adjacent tissues. In contrast, the BRCA1 gene was hypermethylated in breast cancer tissues and showed correspondingly decreased mRNA and protein expression levels. In vitro experiments demonstrated that BCSG1 could promote the proliferation and migration of breast cancer cells. After inhibiting the methylation, the expression of both the BCSG1 and BRCA1 genes were increased. Conclusion: Abnormal methylation patterns of the BCSG1 and BRCA1 genes are associated with the development of breast cancer. Thus, methylatedion analyses of these genes have biomarker potential for breast cancer prognoses.

Characteristics of breast cancer patients tested for germline BRCA1/2 mutations by next-generation sequencing in Ramathibodi Hospital, Mahidol University

INTRODUCTION

Germline mutations in BRCA1/2 are the most common cause of hereditary breast and ovarian cancer (HBOC) syndrome. Few studies published during the past decade reported the prevalence of germline BRCA mutations in Asian patients with breast cancer. We aimed to assess the prevalence and characteristics of Thai patients with breast cancer with germline BRCA1/2 mutations.

METHODS

We retrospectively reviewed all breast cancer patients who were tested for germline BRCA1/2 mutations during 2014-2018. BRCA mutations were detected using next-generation sequencing and confirmed using Sanger sequencing. We analyzed the characteristics of patients with or without BRCA mutations. Disease-free survival (DFS) and the associated factors were determined.

RESULTS

Among 67 patients, 12 (18%) were BRCA1/2 carriers (6 each), 4 (6%) harbored variants of uncertain significance, and 51 (76%) were non-carriers. We discovered two novel BRCA2 frameshift mutations (c.2380delA and c.8855dupT). Mean ages at breast cancer diagnosis of BRCA1, BRCA2, and non-carriers were 39.8, 46.2, and 42.0 years, respectively. The 12 tumors of BRCA carriers were mainly the luminal-B subtype. Two of these tumors were HER2-positive luminal-B, and the triple-negative subtype was not detected. After adjusting for stages and luminal subtypes, BRCA carriers experienced worse 3-year DFS than non-carriers (81.5% vs. 90.3%, HR 2.04 [0.64-6.49], p = .229). The stage at diagnosis was the sole factor significantly associated with 3-year DFS (100%, 84.8%, and 72.7%; stages I, II, and III, respectively).

CONCLUSION

Thai patients with breast cancer with BRCA1/2 mutations were mainly the luminal-B subtypes with worse prognosis than those without mutations.

Pathogenicity Reclassification of Genetic Variants Related to Early-Onset Breast Cancer among Women of Mongoloid Origin

BACKGROUND

Germline alterations in BRCA1, BRCA2, and other genes are responsible for early-onset breast cancer. However, up to 20% of molecular tests report genetic variant of unknown significance (VUS) or novel variants that have never been previously described and their clinical significance are unknown. This study aimed to reclassify variant of unknown significance (VUS) or novel variants by using the ActiveDriveDB database that annotates variants through the lens of sites of post-translational modifications (PTM).

METHODS

Our study included thirty-eighth young Buryat BC patients, belonging to the Mongoloid race and anthropologically to the Central Asia. Genomic DNA was extracted from the peripheral blood lymphocytes using the phenol/chloroform method. DNA library were prepared using the Hereditary Cancer SolutionTM kit (Sophia GENETICS, Switzerland) to cover 27 genes, such as ATM, APC, BARD1, BRCA1, BRCA2, BRIP1, CDH1, CHEK2, EPCAM, FAM175A, MLH1, MRE11A, MSH2, MSH6, MUTYH, NBN, PALB2, PIK3CA, PMS2, PMS2CL, PTEN, RAD50, RAD51C, RAD51D, STK11, TP53, and XRCC2. Paired-end sequencing (2 x 150 bp) was conducted using NextSeq 500 system (Illumina, USA).

RESULTS

We re-examined 135 rare variants (41 VUS, 25 conflicting, 64 benign and 5 new variants). We identified 10 out of 135 (7.4%) mutations that affected the sites of post-translational modification in proteins. Of 135 rare mutations, 1 benign variant was reclassified as network-rewiring - motif loss mutation, 3 VUS and 1 new variant were reclassified as distal PTM- mutations, 2 new and 1 benign variant were classified as proximal PTM- mutations and 1 benign and 1 conflicting variant were classified as direct PTM- mutations.

CONCLUSIONS

For the first time, 7.4% (10 out of 135) of mutations that affected the sites of post-translational modification in proteins were identified among early-onset breast cancer women of Mongoloid origin.

Predicting the Likelihood of Carrying a BRCA1 or BRCA2 Mutation in Asian Patients With Breast Cancer

PURPOSE

With the development of poly (ADP-ribose) polymerase inhibitors for treatment of patients with cancer with an altered BRCA1 or BRCA2 gene, there is an urgent need to ensure that there are appropriate strategies for identifying mutation carriers while balancing the increased demand for and cost of cancer genetics services. To date, the majority of mutation prediction tools have been developed in women of European descent where the age and cancer-subtype distributions are different from that in Asian women.

METHODS

In this study, we built a new model (Asian Risk Calculator) for estimating the likelihood of carrying a pathogenic variant in BRCA1 or BRCA2 gene, using germline BRCA genetic testing results in a cross-sectional population-based study of 8,162 Asian patients with breast cancer. We compared the model performance to existing mutation prediction models. The models were evaluated for discrimination and calibration.

RESULTS

Asian Risk Calculator included age of diagnosis, ethnicity, bilateral breast cancer, tumor biomarkers, and family history of breast cancer or ovarian cancer as predictors. The inclusion of tumor grade improved significantly the model performance. The full model was calibrated (Hosmer-Lemeshow P value = .614) and discriminated well between BRCA and non-BRCA pathogenic variant carriers (area under receiver operating curve, 0.80; 95% CI, 0.75 to 0.84). Addition of grade to the existing clinical genetic testing criteria targeting patients with breast cancer age younger than 45 years reduced the proportion of patients referred for genetic counseling and testing from 37% to 33% (P value = .003), thereby improving the overall efficacy.

CONCLUSION

Population-specific customization of mutation prediction models and clinical genetic testing criteria improved the accuracy of BRCA mutation prediction in Asian patients.

The relationship between night shift work and breast cancer incidence: A systematic review and meta-analysis of observational studies

The purpose of this study was to investigate the relationship between night shift work and breast cancer (BC) incidence. A search was performed in PubMed, EBSCO, Web of Science, and Cochrane Library databases before June 2021. The exposure factor of this study is night shift work, the primary outcome is the risk of BC. A total of 33 observational studies composed of 4,331,782 participants were included. Night shift work increases the risk of BC in the female population (hazard ratio [HR] = 1.20, 95% confidence interval [Cl] = 1.10–1.31, p < 0.001), especially receptor-positive BC, including estrogen receptor (ER)+ BC (HR = 1.35, p < 0.001), progesterone receptor (PR)+ BC (HR = 1.30, p = 0.003), and human epidermal growth factor receptor 2 (HER2)+ BC (HR = 1.42, p < 0.001), but has no effect on HER2− BC (HR = 1.10, p = 0.515) and ER−/PR− BC (HR = 0.98, p = 0.827). The risk of BC was positively correlated with night shift working duration, frequency, and cumulative times. For women who start night work before menopause, night work will increase the incidence of BC (HR = 1.17, p = 0.020), but for women who start night work after menopause, night work does not affect BC (HR = 1.04, p = 0.293). Night work can increase the incidence of BC in the female population. The effect of long working hours, frequency, and the cumulative number of night shifts on BC is influenced by menopausal status.

Association of Interleukin-10 Polymorphism (rs1800896, rs1800871, and rs1800872) With Breast Cancer Risk: An Updated Meta-Analysis Based on Different Ethnic Groups

Background: The interleukin10 (IL-10) gene polymorphisms have been indicated to be associated with breast cancer (BC) risk, but the findings are still controversial. To derive a more precise evaluation, we performed a comprehensive meta-analysis.

Methods: A systematic literature search was conducted using PubMed, Embase, CNKI, China biomedical (CBM), and Google Scholar to 29 March 2020. Revman5.3 and Stata 12.0 software analyzed the data, and the strength of the association was identified using the odds ratio (OR) and the corresponding 95% confidence interval (CI).

Results: A total of 23 studies (7,250 cancer cases and 7,675 case-free controls) were included in this meta-analysis. The results show that IL-10 gene polymorphisms were significantly correlated with BC risk based on subgroup analysis by ethnicity. The IL-10 rs1800896 polymorphism was significantly associated with the risk of BC in Asians (G vs. A: OR = 0.78, 95% CI = 0.65–0.95, p = 0.01; GG vs. AA: OR = 0.51, 95% CI = 0.31–0.84, p = 0.007; GA vs. AA: OR = 0.6, 95% CI = 0.44–0.81, p = 0.0009; GG + GA vs. AA: OR = 0.6, 95% CI = 0.45–0.81, p = 0.0007); Moreover, an increased BC risk in Asians were also associated with the IL-10 rs1800872 polymorphism (AA vs CC: OR = 0.74, 95% CI = 0.55–0.99, p = 0.04; A vs C: OR = 0.85, 95% CI = 0.74–0.98, p = 0.03). In addition, The IL-10 rs1800871 (CT vs. TT: OR = 1.8, 95% CI = 1.03–3.13, p = 0.04) and rs1800872 polymorphism (A vs C: OR = 0.65, 95% CI 0.43–0.98, p = 0.04) were associated with BC risk in Caucasians.

Conclusion: Collectively, this meta-analysis demonstrated that IL-10 rs1800896 and rs1800872 (AA vs. CC; A vs. C) polymorphisms significantly increased the risk of BC in Asians, while the rs1800871 and rs1800872 (A vs. C) were associated with the risk of BC in Caucasians. Therefore, this may provide new ideas for predicting and diagnosing BC susceptibility through the detection of IL-10 gene polymorphism.

Systematic Review Registration: [https://www.crd.york.ac.uk/ PROSPERO], identifier [CRD42021266635].

Impact of BRCA mutation on the survival and risk of contralateral breast cancer in Asian breast cancer patients

PURPOSE

Breast cancer is increasing around the globe, including Asia. We aimed to examine the survival and risk of contralateral breast cancer (CBC) in Asian breast cancer patients with BRCA mutations.

METHODS

A total of 128 breast cancer patients with germline BRCA mutations and 4,754 control breast cancer patients were enrolled. Data on clinical-pathologic characteristics, survival, and CBC were collected from the medical record. The rates of survival and CBC were estimated by Kaplan-Meier method.

RESULTS

The mean age of onset in BRCA mutation carriers was significantly younger than control patients (BRCA vs. Non-BRCA: 43.9 vs. 53.2 years old). BRCA mutation carriers had a higher proportion of triple-negative breast cancer (TNBC) (52%) than control patients (12%, p < 0.001). The risk of CBC was significantly higher in BRCA mutation patients than in control cases (hazard ratio (HR) = 3.95, 95% CI 2.71-5.75); when stratified by genotype, the HRs (95%CI) were 4.84 (3.00-7.82) for BRCA1 and 3.13 (1.78-5.49) for BRCA2 carriers, respectively. Moreover, BRCA1 mutation patients with triple-negative breast cancer (TNBC) as their first breast cancer had the highest risk of CBC (HR = 5.55, 95% CI 3.29-9.34). However, we did not observe any differences in relapse-free survival and overall survival between mutation carriers and control patients.

CONCLUSION

Our study suggest that BRCA patients had a significantly higher risk of developing CBC, particularly for BRCA1 mutation carriers with TNBC as the first breast cancer.

Ethnic Pharmacogenomic Differences in the Management of Asian Patients with Metastatic Prostate Cancer

Progression to metastatic disease occurs in about half of all men who develop prostate cancer (PC), one of the most common cancers in men worldwide. Androgen deprivation therapy has been the mainstay therapy for patients with metastatic PC (mPC) since the 1940s. In the last decade, there has been unprecedented advancement in systemic therapies, e.g., taxane, androgen-signalling pathway inhibitors, and biomarker-driven targeted therapies for various stages of disease, resulting in overall survival improvement. Adding to ongoing controversies over how best to treat these patients is the recognition that ethnicity may influence prognosis and outcomes. This review discusses recent evidence for the impacts of Asian ethnicity specifically, which includes environmental, sociocultural, and genetic factors, on the approach to pharmacological management of mPC. Clear inter-ethnic differences in drug tolerability, serious adverse events (AEs), and genetic heterogeneity must all be considered when dosing and scheduling for treatment, as well as designing future precision studies in PC.

BRCA1/BRCA2 mutation spectrum analysis in South Asia: a systematic review

Objective

Breast cancer (BC) is the most common form of cancer among Asian females. Mutations in the BRCA1/BRCA2 genes are often observed in BC cases and largely increase the lifetime risk of having BC. Because of the paucity of high-quality data on the molecular spectrum of BRCA mutations in South Asian populations, we aimed to explore these mutations among South Asian countries.

Methods

A systematic literature search was performed for the BRCA1 and BRCA2 gene mutation spectrum using electronic databases such as PubMed, EMBASE, and Google Scholar. Twenty studies were selected based on specific inclusion and exclusion criteria.

Results

The 185delAG (c.68_69del) mutation in exon 2 of BRCA1 was the most common recurrent mutation and founder mutation found. Various intronic variants, variants of unknown significance, large genomic rearrangements, and polymorphisms were also described in some studies.

Conclusions

The South Asian population has a wide variety of genetic mutations of BRCA1 and BRCA2 that differ according to countries and ethnicities. A stronger knowledge of various population-specific mutations in these cancer susceptibility genes can help provide efficient strategies for genetic testing.

Incidence of breast cancer subtypes in immigrant and non-immigrant women in Norway

BACKGROUND

Breast cancer incidence differs between non-immigrants and immigrants from low- and middle-income countries. This study investigates whether immigrants also have different subtype-specific incidences.

METHODS

We used national health registries in Norway and calculated subtype-specific incidence rate ratios (IRRs) for invasive breast cancer among women aged 20-75 and 20-49 years between 2005 and 2015. Immigrant groups were classified by country of birth broadly defined based on WHO regional groupings. Subtype was defined using estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor 2 (HER2) status as luminal A-like (ER+ PR+ HER2-), luminal B-like/HER2- (ER+ PR- HER2-), luminal B-like/HER2+ (ER+ PR any HER2+), HER2+ (ER-PR-HER2+) and triple-negative breast cancer (TNBC) (ER-PR-HER2-).

RESULTS

Compared to non-immigrants, incidence of the luminal A-like subtype was lower in immigrants from Sub-Saharan Africa (IRR 0.43 95% CI 0.28-0.66), South East Asia (IRR 0.63 95% CI 0.51-0.79), South Asia (IRR 0.67 95% CI 0.52-0.86) and Eastern Europe (IRR 0.86 95% CI 0.76-0.99). Immigrants from South Asia had higher rates of HER2 + tumors (IRR 2.02 95% CI 1.26-3.23). The rates of TNBC tended to be similar regardless of region of birth, except that women from South East Asia had an IRR of 0.54 (95% CI 0.32-0.91).

CONCLUSIONS

Women from Eastern Europe, Sub-Saharan Africa and Asia had different subtype-specific incidences compared to women from high-income countries (including non-immigrants). These differences in tumor characteristics between immigrant groups should be taken into consideration when planning preventive or screening strategies.

Familial Breast Cancer: Disease Related Gene Mutations and Screening Strategies for Chinese Population

BACKGROUND

About 5%-10% of the breast cancer cases have a hereditary background, and this subset is referred to as familial breast cancer (FBC). In this review, we summarize the susceptibility genes and genetic syndromes associated with FBC and discuss the FBC screening and high-risk patient consulting strategies for the Chinese population.

METHODS

We searched the PubMed database for articles published between January 2000 and August 2021. Finally, 380 pieces of literature addressing the genes and genetic syndromes related to FBC were included and reviewed.

RESULTS

We identified 16 FBC-related genes and divided them into three types (high-, medium-, and low-penetrance) of genes according to their relative risk ratios. In addition, six genetic syndromes were found to be associated with FBC. We then summarized the currently available screening strategies for FBC and discussed those available for high-risk Chinese populations.

CONCLUSION

Multiple gene mutations and genetic disorders are closely related to FBC. The National Comprehensive Cancer Network (NCCN) guidelines recommend corresponding screening strategies for these genetic diseases. However, such guidelines for the Chinese population are still lacking. For screening high-risk groups in the Chinese population, genetic testing is recommended after genetic counseling.

Pathogenic BRCA Variants as Biomarkers for Risk in Prostate Cancer

Simple Summary

Historically, the treatment of prostate cancer was a blanket approach for all. Prostate cancer has not benefitted from targeted treatments based on specific tumour characteristics (ie. Particular genetic or molecular patterns) the way other cancers have. This is important as studies have shown that prostate cancer patients with certain errors in their genes, such as BRCA2 or BRCA1, are more likely to have worse disease and poorer outcome. These patients can be treated successfully with a group of drugs called ‘PARP inhibitors’. This paper examines the prognostic, clinical and therapeutic role of BRCA2/BRCA1 mutations across the evolution of PCa. The impact of the inclusion of BRCA genes on genetic screening will also be outlined.

Abstract

Studies have demonstrated that men with Prostate Cancer (PCa) harboring BRCA2/BRCA1 genetic aberrations, are more likely to have worse disease and a poorer prognosis. A mutation in BRCA2 is known to confer the highest risk of PCa for men (8.6 fold in men ≤65 years) making BRCA genes a conceivable genomic biomarker for risk in PCa. These genes have attracted a lot of research attention however their role in the clinical assessment and treatment of PCa remains complex. Multiple studies have been published examining the relationship between prostate cancer and BRCA mutations. Here BRCA mutations are explored specifically as a biomarker for risk in PCa. It is in this context, we examined the prognostic, clinical and therapeutic role of BRCA2/BRCA1 mutations across the evolution of PCa. The impact of the inclusion of BRCA genes on genetic screening will also be outlined.

Identification of N6-Methyladenosine-Related LncRNAs for Predicting Overall Survival and Clustering of a Potentially Novel Molecular Subtype of Breast Cancer

We aimed to identify a signature comprising N6-methyladenosine (m6A)-related long non-coding RNAs (lncRNAs) and molecular subtypes associated with breast cancer (BRCA). We obtained data of BRCA samples from The Cancer Genome Atlas database. The m6A-related lncRNA prognostic signature (m6A-LPS) included 10 lncRNAs previously identified as prognostic m6A-related lncRNAs and was constructed using integrated bioinformatics analysis and validated. Accordingly, a risk score based on the m6A-LPS signature was established and shown to confirm differences in survival between high-risk and low-risk groups. Three distinct genotypes were identified, whose characteristics included features of the tumor immune microenvironment in each subtype. Our results indicated that patients in Cluster 2 might have a worse prognostic outcome than those in other clusters. The three genotypes and risk subgroups were enriched in different biological processes and pathways, respectively. We then constructed a competing endogenous RNA network based on the prognostic m6A-related lncRNAs. Finally, we validated the expression levels of target lncRNAs in 72 clinical samples. In summary, the m6A-LPS and the potentially novel genotype may provide a theoretical basis for further study of the molecular mechanism of BRCA and may provide novel insights into precision medicine.

Changing Patterns in Clinicopathological Characteristics of Breast Cancer and Prevalence of BRCA Mutations: Analysis in a Rural Area of Southern China

PURPOSE

Although the burden of breast cancer remains especially high in rural China, data on the clinicopathological characteristics and prevalence of the breast cancer susceptibility gene 1/2 (BRCA1/2) mutations in patients with breast cancer remain limited. We investigated the clinicopathological characteristics, changing patterns, and prevalence of BRCA1/2 mutations in patients with breast cancer.

PATIENTS AND METHODS

The clinicopathological characteristics of 3712 women with pathologically confirmed primary breast cancer treated at Meizhou People's Hospital between January 2005 and December 2018 were evaluated. The prevalence of BRCA1/2 mutations in 340 patients with breast cancer diagnosed between January 2017 and September 2018 was also evaluated.

RESULTS

The median age at diagnosis was 49±10.5 (range, 20-94) years. Positivity for estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) was observed in 59.0%, 52.5%, and 24.9% of patients, respectively. Time trend analysis revealed that an increasing trend was observed for age at diagnosis (p = 0.001), proportion of patients without a reproductive history (p < 0.001), postmenopausal patients (p = 0.001), invasive pathological cancer type (p = 0.008), ER-positive rate (p < 0.001), PR-positive rate (p = 0.008), and HER2-positive rate (p < 0.001). Compared with patients without BRCA1/2 mutations, those with BRCA1/2 mutations were more likely to have a family history of breast or ovarian cancer (p < 0.001) and have triple-negative breast cancer (TNBC) (p < 0.001). Family history of breast or ovarian cancer (odds ratio [OR], 103.58; 95% confidence interval [CI], 20.58-521.45; p < 0.001) and TNBC subtype (OR, 5.97; 95% CI, 1.16-30.90; p = 0.033) were independent predictors for BRCA1/2 mutation.

CONCLUSION

The clinicopathological characteristics of patients with breast cancer in this rural area have changed during the past decade. BRCA1/2 testing should be performed in patients with breast cancer with a family history of breast or ovarian cancer and TNBC.

The relationship between dairy products intake and breast cancer incidence: a meta-analysis of observational studies

Background

The effect of dairy products intake on breast cancer (BC) is highly controversial. This study aims to investigate the relationship between dairy intake and BC incidence.

Methods

A search was carried out in PubMed, EBSCO, Web of Science, and Cochrane Library databases before January 2021. The primary objective was the risk of BC and intake of dairy products were exposure variables.

Results

The meta-analysis comprised 36 articles with 1,019,232 participants. Total dairy products have a protective effect on female population (hazard ratio (HR) =0.95, 95% confidence interval (CI) =0.91–0.99, p = 0.019), especially for estrogen receptor-positive (ER+) (HR = 0.79, p = 0.002) and progesterone receptor-positive (PR+) BC (HR = 0.75, p = 0.027). For ER+/PR+ BC, there is a trend of protection, but it has not reached statistical significance (HR = 0.92, p = 0.075). Fermented dairy products can reduce BC risk in postmenopausal population (HR = 0.96, 95%CI = 0.93–0.99, p = 0.021), but have no protective effect on premenopausal population (HR = 0.98, 95%CI = 0.94–1.03, p = 0.52). Non-fermented dairy products have no significant effect on BC occurrence (p > 0.05). High-fat dairy products are harmful to women, without statistical difference (HR = 1.06, 95%CI = 1.00–1.13, p = 0.066). On the contrary, low-fat dairy products can protect the premenopausal population (HR = 0.94, 95%CI = 0.89–1.00, p = 0.048).

Conclusion

The intake of dairy products can overall reduce BC risk in the female population, but different dairy products have varying effects on different BC subtypes and menopausal status.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08854-w.

Diagnostics of hereditary cancer syndromes by ngs. A database creation experience

Background: More than 500 thousand new cases of malignant neoplasms are registered annually in the Russian Federation, of which more than 50 thousand new cases are due to hereditary forms. Improving the diagnosis of these diseases will make it possible to detect tumors at the early stages and take timely preventive and therapeutic measures. Aims: Creation of a database and development of a software for the NGS data analysis for the prevention and early diagnosis of hereditary forms of oncological diseases. Methods: The present study used 636 DNA samples obtained from cancer patients with a high hereditary risk or a burdened family history. DNA was isolated from blood lymphocytes. DNA libraries were prepared with a KAPA Target Enrichment Panel (Roche). The panel included probes for targeted enrichment of the coding region of 44 genes. NGS was performed on the MiSeq platform (Illumina). Results: We identified 65 pathogenic/ probably pathogenic nucleotide sequence variants in 96 patients in the ATM, BLM, BRCA1, BRCA2, CHEK2, EPCAM, MEN1, MLH1, MSH2, MSH3, MSH6, MUTYH, PALB2, TP53 genes. We also identified 2858 nucleotide sequence variants of unknown clinical significance. Conclusions: We have created a local database that contains both genetic variants and clinical and anamnestic data. The database contains 4763 nucleotide sequence variants at the moment, among which 2522 are unique variants identified in a single patient.

Mutations in BRCA-related breast and ovarian cancer in the South African Indian population: A descriptive study

Knowledge of the genetic landscape of a specific population group is vital for population-specific diagnosis and treatment of familial breast cancer. Although BRCA-related diagnostic testing has long been implemented in South Africa, the genotyping approach previously failed for the SA Indian population as it was based on other SA population groups. Because this population is uniquely admixed, the lack of population-specific data resulted in the implementation of comprehensive mutation screens for BRCA1/2. A total of 223 female patients were screened for clinically actionable variants. High-resolution melting analysis (HRMA) was used to screen 88 patients for DNA alterations in the coding and splice site boundaries of BRCA1 exons 2-9, BRCA1 exons 11-23, BRCA2 exons 2-9 and BRCA2 exons 12-27. The protein truncation test (PTT) was used to screen the three larger exons (BRCA1 exon 10 and BRCA2 exons 10 and 11) for protein termination changes. Multiplex ligation-dependent probe amplification (MLPA) was used to determine the presence of larger indels and possible copy number differences. Next Generation Sequencing (NGS) was performed on the remaining 135 samples. All potential variants were confirmed by performing Sanger DNA sequencing. The search revealed 28 different pathogenic heterozygotic variants, together with nine variants of unknown significance (VUS). The results suggested that the SA Indian population represents a different genetic admixture compared to that of mainland India, as only five pathogenic variants corresponded to those reported for mainland India. Familial breast cancer testing for SA Indian patients should therefore be performed as comprehensively as possible as the pathogenic variants seem to be family- rather than population-specific. Furthermore, predictive testing of family members will contribute to relieve the financial burden on the country's healthcare system, as increased surveillance and appropriate management could prevent disease.

Integrated Analyses Reveal the Multi-Omics and Prognostic Characteristics of ATP5B in Breast Cancer

The beta subunit of F1Fo-ATP synthase (ATP5B) has been demonstrated to play an essential role in tumor progression and metastasis. However, there has been no comprehensive pan-cancer multi-omics analysis of ATP5B, while the clinical relevance of ATP5B and its potential mechanism in regulating breast cancer are still poorly understood. In this study, we demonstrated that ATP5B has a higher frequency of amplification than deletion in most cancer types, and the copy number variation (CNV) of ATP5B was significantly positively correlated with its mRNA expression level. DNA methylation analysis across pan-cancer also revealed a strong correlation between ATP5B expression and epigenetic changes. We identified 6 significant methylation sites involved in the regulation of ATP5B expression. Tissue microarrays (TMA) from 129 breast cancer samples, integrated with multiple additional breast cancer dataset, were used to evaluate the ATP5B expression and its correlation with prognosis. Higher levels of ATP5B expression were consistently associated with a worse OS in all datasets, and Cox regression analysis suggested that ATP5B expression was an independent prognostic factor. Gene enrichment analysis indicated that the gene signatures of DNA damage recognition, the E-cadherin nascent pathway and the PLK1 pathway were enriched in ATP5B-high patients. Moreover, somatic mutation analysis showed that a significant different mutation frequency of CDH1 and ADAMTSL3 could be observed between the ATP5B-high and ATP5B-low groups. In conclusion, this study reveals novel significance regarding the genetic characteristics and clinical value of ATP5B highlighted in predicting the outcome of breast cancer patients.

Baseline knowledge and receptiveness to genetic testing for hereditary breast and ovarian cancer syndromes in Chinese high-risk females

Limited studies have examined the pre-counselling knowledge and attitudes of high-risk women on hereditary breast and ovarian cancer (HBOC) syndromes genetic screening in Asia Pacific regions, particularly among Chinese. After controlling cost, an intrinsic barrier to undertake such screening, comprehensive understanding of the baseline characteristics of this cohort towards HBOC genetic counselling and testing service (GT) could be sought. This study aimed at exploring the baseline knowledge, possible motivators, barriers, and decisional factors of undertaking such service. One hundred and forty-two Southern Hong Kong Chinese high-risk females (89.4% with cancer history; 10.6% were cancer-free at-risk family members) completed a questionnaire right before their pre-testing GT. Results showed that perceived benefits to self and family members with reference to cancer prevention are important decisional motivators. A sponsored cancer genetic testing service in this cohort was crucial as 71.3% would not have opted for self-financed screening. Pre-testing and post-testing counselling were essential, particularly for older and less educated high-risk individuals. More importantly, after thorough pre-counselling with Q&A session, the entire cohort in this study gave written consent to undertake GT. Moreover, those proven to be germline pathogenic variant carriers were willing to share the information with family members and successfully persuaded them to pursue GT.

Comprehensive Study of Germline Mutations and Double-Hit Events in Esophageal Squamous Cell Cancer

Esophageal squamous cell cancer (ESCC) is the eighth most common cancer around the world. Several reports have focused on somatic mutations and common germline mutations in ESCC. However, the contributions of pathogenic germline alterations in cancer susceptibility genes (CSGs), highly frequently mutated CSGs, and pathogenically mutated CSG-related pathways in ESCC remain unclear. We obtained data on 571 ESCC cases from public databases and East Asian from the 1000 Genomes Project database and the China Metabolic Analytics Project database to characterize pathogenic mutations. We detected 157 mutations in 75 CSGs, accounting for 25.0% (143/571) of ESCC cases. Six genes had more than five mutations: TP53 (n = 15 mutations), GJB2 (n = 8), BRCA2 (n = 6), RECQL4 (n = 6), MUTYH (n = 6), and PMS2 (n = 5). Our results identified significant differences in pathogenic germline mutations of TP53, BRCA2, and RECQL4 between the ESCC and control cohorts. Moreover, we identified 84 double-hit events (16 germline/somatic double-hit events and 68 somatic/somatic double-hit events) occurring in 18 tumor suppressor genes from 83 patients. Patients who had ESCC with germline/somatic double-hit events were diagnosed at younger ages than patients with the somatic/somatic double-hit events, though the correlation was not significant. Fanconi anemia was the most enriched pathway of pathogenically mutated CSGs, and it appeared to be a primary pathway for ESCC predisposition. The results of this study identified the underlying roles that pathogenic germline mutations in CSGs play in ESCC pathogenesis, increased our awareness about the genetic basis of ESCC, and provided suggestions for using highly mutated CSGs and double-hit features in the early discovery, prevention, and genetic counseling of ESCC.

The role of genomics in global cancer prevention

Despite improvements in the understanding of cancer causation, much remains unknown regarding the mechanisms by which genomic and non-genomic factors initiate carcinogenesis, drive cell invasion and metastasis, and enable cancer to develop. Technological advances have enabled the analysis of whole genomes, comprising thousands of tumours across populations worldwide, with the aim of identifying mutation signatures associated with particular tumour types. Large collaborative efforts have resulted in the identification and improved understanding of causal factors, and have shed light on new opportunities to prevent cancer. In this new era in cancer genomics, discoveries from studies conducted on an international scale can inform evidence-based strategies in cancer control along the cancer care continuum, from prevention to treatment. In this Review, we present the relevant history and emerging frontiers of cancer genetics and genomics from the perspective of global cancer prevention. We highlight the importance of local context in the adoption of new technologies and emergent evidence, with illustrative examples from worldwide. We emphasize the challenges in implementing important genomic findings in clinical settings with disparate resource availability and present a conceptual framework for the translation of such findings into clinical practice, and evidence-based policies in order to maximize the utility for a population.

Targeting Loss of Heterozygosity: A Novel Paradigm for Cancer Therapy

Loss of heterozygosity (LOH) is a common genetic event in the development of cancer. In certain tumor types, LOH can affect more than 20% of the genome, entailing loss of allelic variation in thousands of genes. This reduction of heterozygosity creates genetic differences between tumor and normal cells, providing opportunities for development of novel cancer therapies. Here, we review and summarize (1) mutations associated with LOH on chromosomes which have been shown to be promising biomarkers of cancer risk or the prediction of clinical outcomes in certain types of tumors; (2) loci undergoing LOH that can be targeted for development of novel anticancer drugs as well as (3) LOH in tumors provides up-and-coming possibilities to understand the underlying mechanisms of cancer evolution and to discover novel cancer vulnerabilities which are worth a further investigation in the near future.

Reliable assessment of BRCA1 and BRCA2 germline variants by next-generation sequencing: a multicenter study

BACKGROUND

BRCA1/2 gene mutation testing, based on next-generation sequencing (NGS), has been gradually applied in the clinic to serve as preventive early screening for predisposed individuals or to provide treatment options for patients with hereditary breast or ovarian cancers. Here, we evaluated the accuracy of NGS-based mutation detection in BRCA1/2 and the consistency in variant interpretation among clinical laboratories to find the possible reasons underlying inaccurate results and discrepant variant interpretation.

METHODS

Laboratories were asked to use their routine procedures to detect six mimetic DNA samples with different BRCA1/2 germline variants. The results of variant detection were required to be submitted via a web-based evaluation system and were automatically scored, according to predefined criteria. The variant interpretation report, including the detailed clinical evidence, was summarized and analyzed for reasons underlying inconsistent results.

RESULTS

Overall, only 55.2% (16/29) of laboratories, whose detection score was higher than 90 points, was found to be an acceptable detection capability level. 82.9% (29/35) of the errors were genotype errors. The variant classification results were generally consistent, and 77.8% (7/9) of the variants were given the consistent classification answer. Only two single nucleotide variants (SNVs) had a discrepant classification opinion across laboratories.

CONCLUSIONS

The BRCA1/2 variant detection performance should be further improved, especially in reporting the correct genome coordinates. Inconsistent variant classification may be a result of the different clinical pieces of evidence collected by the laboratories. However, discordant clinical evidence also appeared within the same classification results. Therefore, our study provided clear clinical evidence assessment strategies for BRCA1/2 variants, which was aimed at obtaining a consistent variant classification strategy for providing accurate clinical reports to the clinicians.

Targeted sequencing of crucial cancer causing genes of breast cancer in Saudi patients

Breast cancer is the most common cancer among women worldwide, causing 15% of cancer-related deaths among women. Breast cancer incidence rate is increasing in most countries. In Saudi Arabia, breast cancer constitutes nearly 22% of the newly diagnosed cancer cases in women. Breast cancer incidence in the women population of Saudi Arabia is 25.9%, with 18.2% mortality. In this study, targeted sequencing of 164 selected genes was performed on germline and somatic DNA derived from the blood and tissue samples of 50 breast cancer patients using customized panel on Ion torrent platform. This study focused on the identification of genetic variations of different cancer-causing genes, raising the hope for identification of personalized prognosis. After final filtration and validation, we found protein-truncating, non-synonymous missense, and splice site mutations in the known susceptibility genes for breast cancer. We identified a total of 14 point mutations and one deletion in BRCA1, BRCA2, and RAD50 genes from the BRCA panel analysis of breast cancer samples. In the customized panel analysis, we identified 37 potential mutations in 25 breast cancer risk associated genes. Out of these, most mutations were observed in TP53. After filtration, we observed 7 mutations in TP53 genes (n = 7:- one stop gain (p.R81X), four non-synonymous (p.R81X, p.Y88C, p.R141H, and p.V25D), and two deletions (c.59delC and c.327delC)). Among the mutations detected in our study, TP53 (p.R81X), VHL (p.E52X), and BRCA2 (p.K3326X) mutations, which lead to an aberrant transcript with a premature stop codon, were reported for the first time in breast cancer patients from Saudi Arabia. Our study will help in identifying the damaging mutations and predisposing genes in Saudi breast cancer patients.

Ethnic-specific BRCA1/2 variation within Asia population: evidence from over 78 000 cancer and 40 000 non-cancer cases of Indian, Chinese, Korean and Japanese populations

BACKGROUND

Germline mutation in BRCA1 and BRCA2 (BRCA) is genetic predisposition for breast and ovarian cancer. Identification of mutation carriers is a critical step to prevent and treat the cancer in the mutation carriers. Human BRCA variation has been well determined as ethnic-specific by studies in Ashkenazi Jewish, Polish and Icelandic populations in the 1990s. However, sufficient evidence is lacking to determine if ethnic-specific BRCA variation is also present in Asia population, which is the largest and the most diversified in modern humans. Our current study aims to investigate ethnic-specific BRCA variation in Asian population.

METHODS

We performed a comprehensive data mining to collect BRCA variation data in Indian, Chinese, Korean and Japanese populations derived from over 78 000 cancer and 40 000 non-cancer cases. We standardised all BRCA variation data following the international standard. We made a systematic comparison between the datasets including variant composition, variation spectrum, variant type, clinical class, founder mutation and high-frequent variants.

RESULTS

Our analysis showed that over half of the Asian BRCA variants were Asian-specific, and significant differences were present between the four Asia populations in each category analysed.

CONCLUSION

Data from our study reveal that ethnic-specific BRCA variation is commonly present in Asia population as existing in non-Asian populations. Our study indicates that ethnicity should be an important factor to consider in prevention and treatment of BRCA mutation-related cancer in the Asia population. We recommend that the current BRCA variation databases should include ethnic variation information in order to function as true global BRCA references.

BRCA1 Is a Novel Prognostic Indicator and Associates with Immune Cell Infiltration in Hepatocellular Carcinoma

The breast cancer gene 1 (BRCA1) is a tumor suppressor, and mutations or epigenetic inactivation will increase the risk of breast cancer oncogenesis. The current research aimed to explore the relationship between BRCA1 expression, prognosis, and tumor immunity in hepatocellular carcinoma (HCC). In this study, BRCA1 expression was analyzed via multiple online databases and its association with clinical characteristics, prognosis and genetic alterations was identified using the original The Cancer Genome Atlas-liver hepatocellular carcinoma cohorts. DNA methylation sites and their prognostic values were analyzed using MethSurv. The correlations between BRCA1 and immune infiltration were investigated via Tumor Immune Estimation Resource. As results, BRCA1 was significantly upregulated in tumor tissues in multiple HCC cohorts. Besides, high BRCA1 expression was correlated with race, advanced T stage, clinical stage, poor tumor grade, MSI status, and worse prognosis. Notably, BRCA1 expression was positively correlated with infiltration levels of B cells, CD4+ T cells, CD8+ T cells, neutrophils, macrophages, and dendritic cells. The current findings imply that BRCA1 is associated with prognosis and immune infiltration, laying foundations for in-depth research on the role of BRCA1 in HCC.

Investigation into the origins of an ancient BRCA1 founder mutation identified among Chinese families in Singapore

Identification of ancestry-specific pathogenic variants is imperative for diagnostic, treatment, management and prevention strategies, and to understand penetrance/modifiers on risk. Our study aimed to determine the clinical significance of a recurrent BRCA1 c.442-22_442-13del variant of unknown significance identified among 13 carriers from six Chinese families, all with a significant history of breast and/or ovarian cancer. We further aimed to establish whether this was due to a founder effect and explore its origins. Haplotype analysis, using nine microsatellite markers encompassing 2.5 megabase pairs around the BRCA1 locus, identified a common haploblock specific to the variant carriers, confirming a founder effect. Variant age was estimated to date back 77.9 generations to 69 bc using the Gamma approach. On principal component analysis using single nucleotide polymorphisms merged with 1000 Genomes dataset, variant carriers were observed to overlap predominantly with the southern Han Chinese population. To determine pathogenicity of the variant, we assessed the functional effect on RAD51 foci formation as well as replication fork stability upon induction of DNA damage and observed an impaired DNA repair response associated with the variant. In summary, we identified an ancient Chinese founder mutation dating back 77.9 generations, possibly common among individuals of southern Han Chinese descent. Using evidence from phenotypic/family history studies, segregation analysis and functional characterization, the BRCA1 variant was reclassified from uncertain significance to pathogenic.

New germline mutations in non-BRCA genes among breast cancer women of Mongoloid origin

In accordance with the Asian BRCA Consortium data, there is a significant difference in incidence rate of breast cancer depending on age, as well as spectrum and prevalence of BRCA1/2 mutations between Mongoloid (East Asian) and Caucasoid (European) people. However, European strategies to identify familial BC are still applied to the Asian population, including Russian Mongoloids (Khakas, Buryats, Tyvans and Yakuts and others). The main purpose of the study was to identify molecular changes associated with hereditary BC in Russian Mongoloid BC patients (Buryats). Thirty-nine patients were included in the study. Genomic DNA extracted from lymphocytes was used to prepare DNA-libraries. Target sequencing was designed to cover 27 genes, such as ATM, APC, BARD1, BRCA1, BRCA2, BRIP1, CDH1, CHEK2 and others. Paired-end sequencing (2 × 150 bp) was conducted on a NextSeq 500 system (Illumina, USA). Three pathogenic mutations in non-BRCA genes were found (prevalence of 8%). The pathogenic mutations were found in the RAD51D and PTEN genes. The pathogenic variant in the RAD51D gene (rs137886232, NC_000017.10:g.33428366G>A, p.R141X) was observed in two unrelated individuals aged under 40. One of these patients had a family history of late-onset stomach cancer in second-degree relatives. The pathogenic mutation in the PTEN gene (rs786201044, NC_000010.10:g.89692922T>C, p.C136R) was observed in a 38 years old breast cancer patient with no family history. In our study, we first describe pathogenic mutations in RAD51D and PTEN genes found in young Buryat patients.

Comparison of suspected Lynch syndrome patients carrying BRCA and BRCA-like variants with Lynch syndrome probands: Phenotypic characteristics and pedigree analyses

Background

Colorectal cancer (CRC) patients diagnosed with Lynch syndrome (LS) are recommended genetic testing. Increasing numbers of germline variants involved in homologous recombination have been identified in suspected LS patients. This study compared phenotypic the characteristics of suspected LS patients carrying BRCA and BRCA‐like variants with those of LS patients.

Methods

Forty‐two patients carrying pathogenic variants of DNA mismatch repair (MMR) genes (MMR group), 9 carrying BRCA variants, and 11 carrying BRCA‐like variants (BRCA/BRCA‐like group) who met LS clinical criteria were enrolled in this study. Clinical characteristics, pedigrees, and survival rates were compared and BRCA variants were analyzed.

Results

The earliest CRC‐onset age and tumor differentiation were higher in the BRCA/BRCA‐like group than in the MMR group. Metachronous CRCs were more numerous in the MMR group, resulting in a higher progression‐free survival rate in the BRCA/BRCA‐like group. Extra‐colorectal cancers were more frequently observed in the BRCA/BRCA‐like group. BRCA2 and BRCA1 variants were clustered in exons 11 and 4/7, respectively.

Conclusion

BRCA and BRCA‐like variants in CRC patients with LS showed moderate penetrance. BRCA/BRCA‐like variant carriers had a higher risk for extra‐colorectal cancers. Surveillance of susceptible organs other than the intestine should be performed for probands and affected family members.

Clinical Characteristics of Korean Breast Cancer Patients Who Carry Pathogenic Germline Mutations in Both BRCA1 and BRCA2: A Single-Center Experience

There are few reports of breast cancer patients who carry germline mutations in both germline breast cancer susceptibility genes 1 (gBRCA1) and 2 (gBRCA2). In this study, we analyzed the clinical, pathological, and genomic characteristics of Korean breast cancer patients with both gBRCA1 and gBRCA2 mutations. Medical records of patients who received gBRCA1 and gBRCA2 testing at Samsung Medical Center between January 2007 to October 2018 were retrospectively reviewed. Genomic DNA was isolated from peripheral blood leukocytes. Among a total of 2720 patients, four patients with both gBRCA1 and gBRCA2 mutations were identified (4/2720; 0.14%). Seven patients who had a gBRCA1 mutation and gBRCA2 variants of uncertain significance (VUS) were also identified. In those patients with both gBRCA1 and gBRCA2 mutations, the mean age at diagnosis for breast cancer was 36 years (range, 31–43 years). All four tumors were infiltrating ductal carcinomas and three of the tumors were estrogen receptor-negative, progesterone receptor-negative, and human epidermal growth factor receptor 2-negative (triple-negative). All four patients who carried germline mutations in both BRCA1 and BRCA2 had a family history of breast/ovarian cancer. Pathologic stage was II in three patients and I in one patient. Breast cancer patients with both gBRCA1 and gBRCA2 mutations were rare, young at diagnosis, and all but one tumor was triple-negative based on our single-center experience.

Germline Mutation in 1338 BRCA-Negative Chinese Hereditary Breast and/or Ovarian Cancer Patients: Clinical Testing with a Multigene Test Panel

Differences in the mutation spectrum across ethnicities suggest the importance of identifying genes in addition to common high penetrant genes to estimate the associated breast cancer risk in China. A total of 1338 high-risk breast cancer patients who tested negative for germline BRCA1, BRCA2, TP53, and PTEN mutations between 2007 and 2017 were selected from the Hong Kong Hereditary Breast Cancer Family Registry. Patient samples were subjected to next-generation DNA sequencing using a multigene panel (Color Genomics). All detected pathogenic variants were validated by bidirectional DNA sequencing. The sequencing data were coanalyzed by a bioinformatics pipeline developed in-house. Sixty-one pathogenic variants (4.6%) were identified in this cohort in 11 cancer predisposition genes. Most carriers (77.1%) had early onset of breast cancer (age <45 years), 32.8% had family members with breast cancer, and 11.5% had triple-negative breast cancer. The most common mutated genes were PALB2 (1.4%), RAD51D (0.8%), and ATM (0.8%). A total of 612 variants of unknown significance were identified in 494 patients, and 87.4% of the variants of unknown significance were missense mutations. Pathogenic variants in cancer predisposition genes beyond BRCA1, BRCA2, TP53, and PTEN were detected in an additional 4.6% of patients using the multigene panel. PALB2 (1.4%) and RAD51D (0.8%) were the most commonly mutated genes in patients who tested mutation negative by a four-gene panel.

Germline mutations of multiple breast cancer-related genes are differentially associated with triple-negative breast cancers and prognostic factors

Genetic testing for BRCA1/2 mutations has become the standard clinical practice. Recent findings suggest the clinical significance of multigene panel testing of BRCA1/2 and other cancer-related genes. However, the clinical features of patients with breast cancer with germline mutations identified using multigene panels remain unclear. In this study, DNA samples from 583 Chinese women with breast cancer were subjected to target sequencing for 54 cancer-related genes using a pre-capture pooling method followed by next-generation sequencing. We identified 79 pathogenic germline mutations in 21 cancer-related genes. Forty-five patients (7.7%) harbored BRCA1/2 mutations, and 38 patients (6.5%) carried pathogenic mutations in the remaining 19 genes. PALB2 was the most commonly (1.2%) mutated gene other than BRCA1/2. Most of the identified pathogenic mutations were novel, suggesting mutation screening by using multigene panel testing is important particularly for non-European populations. Mutations in BRCA1/2 and the other cancer-related genes were differentially associated with clinical features. BRCA1 mutation carriers were strongly associated with triple-negative breast cancer (TNBC), whereas BRCA2 mutation carriers were not. Tumors in BRCA1-mutation carriers had a high histological grade. Patients with BRCA2-mutated breast cancers were likely to develop E-cadherin-negative tumors with bone metastases. Furthermore, mutations in PALB2 were strongly associated with TNBC. We demonstrated the usefulness of multigene panel testing and observed that a substantial proportion of patients with breast cancer had hereditary risk factors. Identifying differential associations between mutation status and clinical features will advance our understanding regarding the pathologies of this heterogeneous disease.

Profiling of the germline mutation BRCA1: p.Ile1845fs in a large cohort of Han Chinese breast cancer

Background

Breast cancer is a one of the malignant carcinomas partially caused by genetic risk factors. Germline BRCA1 gene mutations are reportedly associated with breast cancers. Identification of BRCA1 mutations greatly improves the preventive strategies and management of breast cancer. The aim of our study was to investigate the frequency of the deleterious BRCA1: p.Ile1845fs variant in breast carcinomas, as well as the correlation between p.Ile1845fs variant with clinicopathological parameters and clinical outcomes.

Results

A total of 23,481 clinically high-risk patients with breast cancer and 6489 healthy controls were recruited for p.Ile1845fs variant sequencing (either sanger or next generation sequencing). We identified 94 breast cancer patients (0.40%, 94/23481) as well as 11 healthy controls (0.17%, 11/6489) carried p.Ile1845fs variant. BRCA1: p.Ile1845fs variant showed a higher frequency in patients with TNBC molecular typing (20.21%, 19/94) and family history (37.23%, 35/94) compared with non-carriers (P = 3.62E-6 and 0.034, respectively). According to our data, we advanced the frequency of p.Ile1845fs variant and we confirmed that BRCA1: p.Ile1845fs variant was associated with increased risk of breast cancer (OR = 2.36, 95%CI = 1.26–4.89, P = 0.004).

Conclusions

BRCA1: p.Ile1845fs variant was a frequently pathogenic mutation in breast cancer in Han Chinese women and our data may be helpful for diagnosis and therapy of breast cancer.

Insights Into Breast Cancer in the East vs the West: A Review

Importance

During the past few decades, the incidence of breast cancer (BC) has been increasing rapidly in East Asia, and BC is currently the most common cancer in several countries. The rising incidence is likely related to changing lifestyle and environmental factors in addition to the increase in early diagnosis with BC awareness and screening. The understanding and management of BC are generally based on research and data from the West. However, emerging differences in BC epidemiology and tumor and host biology in Asian populations may be clinically relevant.

Observations

A higher proportion of premenopausal BCs occur in Asia, although this factor is possibly an age-cohort effect. Although the relative frequencies of different immunohistochemical subtypes of BC may be similar between the East and West, the higher prevalence of luminal B subtypes with more frequent mutations in TP53 may be confounded by disparities in early detection. In addition, Asian BCs appear to harbor a more immune-active microenvironment than BCs in the West. The spectra of germline mutations in BC predisposition genes and single-nucleotide polymorphisms contributing to BC risk vary with ethnicity as well. Differences in tolerability of certain cytotoxic and targeted agents used in BC treatment may be associated with pharmacogenomic factors, whereas the lower body mass of the average woman in East Asia may contribute to higher toxicities from drugs administered at fixed doses. Phenotypic characteristics, such as lower breast volume, may influence the type of surgery performed in East Asian women. On the other hand, increased breast density may affect the sensitivity of mammography in detecting BCs, limiting the benefits of screening mammography.

Conclusions and Relevance

Breast cancer has become a major health problem in Asia. The inclusion of more women from Asia in clinical trials and epidemiologic and translational studies may help unravel the interethnic heterogeneity of BCs and elucidate the complex interplay between environmental and intrinsic factors in its pathogenesis. These insights may help to refine prevention, diagnosis, and management strategies for BC in the setting of ethnic diversity.

A germline mutation in Rab43 gene identified from a cancer family predisposes to a hereditary liver-colon cancer syndrome

Background

Hereditary cancer syndromes have inherited germline mutations which predispose to benign and malignant tumors. Understanding of the molecular causes in hereditary cancer syndromes has advanced cancer treatment and prevention. However, the causal genes of many hereditary cancer syndromes remain unknown due to their rare frequency of mutation.

Methods

A large Chinese family with a history of hereditary liver-colon cancer syndrome was studied. The genomic DNA was extracted from the blood samples of involved family members, whole-exome sequencing was performed to identify genetic variants. Functional validation of a candidate variant was carried out using gene expression, gene knockout and immunohistochemistry.

Results

The whole-exome of the proband diagnosed with colon cancer was sequenced in comparison with his mother. A total of 13 SNVs and 16 InDels were identified. Among these variants, we focused on a mutation of Rab43 gene, a GTPase family member involving in protein trafficking, for further validation. Sanger DNA sequencing confirmed a mutation (c: 128810106C > T, p: A158T) occurred in one allele of Rab43 gene from the proband, that heterozygous mutation also was verified in the genome of the proband’s deceased father with liver cancer, but not in his healthy mother and sister. Ectopic expression of the Rab43 A158T mutant in Huh7 cells led to more enhanced cell growth, proliferation and migration compared to the expression of wild type Rab43. Conversely, knockout of Rab43 in HepG2 cells resulted in slow cell growth and multiple nuclei formation and impaired activation of Akt. Finally, a positive correlation between the expression levels of Rab43 protein and cancer development in that family was confirmed.

Conclusions

A germline mutation of Rab43 gene is identified to be associated with the onset of a familial liver-colon cancer syndrome. Our finding points to a potential role of protein trafficking in the tumorigenesis of the familial cancer syndrome, and helps the genetic counseling to the affected family members.

Electronic supplementary material

The online version of this article (10.1186/s12885-019-5845-4) contains supplementary material, which is available to authorized users.