Dissecting the heterogeneity and tumorigenesis of BRCA1 deficient mammary tumors via single cell RNA sequencing.

Background: BRCA1 plays critical roles in mammary gland development and mammary tumorigenesis. And loss of BRCA1 induces mammary tumors in a stochastic manner. These tumors present great heterogeneity at both intertumor and intratumor levels. Methods: To comprehensively elucidate the heterogeneity of BRCA1 deficient mammary tumors and the underlying mechanisms for tumor initiation and progression, we conducted bulk and single cell RNA sequencing (scRNA-seq) on both mammary gland cells and mammary tumor cells isolated from Brca1 knockout mice. Results: We found the BRCA1 deficient tumors could be classified into four subtypes with distinct molecular features and different sensitivities to anti-cancer drugs at the intertumor level. Whereas within the tumors, heterogeneous subgroups were classified mainly due to the different activities of cell proliferation, DNA damage response/repair and epithelial-to-mesenchymal transition (EMT). Besides, we reconstructed the BRCA1 related mammary tumorigenesis to uncover the transcriptomes alterations during this process via pseudo-temporal analysis of the scRNA-seq data. Furthermore, from candidate markers for BRCA1 mutant tumors, we discovered and validated one oncogene Mrc2, whose loss could reduce mammary tumor growth in vitro and in vivo. Conclusion: Our study provides a useful resource for better understanding of mammary tumorigenesis induced by BRCA1 deficiency.

Homologous recombination proficiency in ovarian and breast cancer patients.

Homologous recombination and DNA repair are important for genome maintenance. Genetic variations in essential homologous recombination genes, including BRCA1 and BRCA2 results in homologous recombination deficiency (HRD) and can be a target for therapeutic strategies including poly (ADP-ribose) polymerase inhibitors (PARPi). However, response is limited in patients who are not HRD, highlighting the need for reliable and robust HRD testing. This manuscript will review BRCA1/2 function and homologous recombination proficiency in respect to breast and ovarian cancer. The current standard testing methods for HRD will be discussed as well as trials leading to approval of PARPi's. Finally, standard of care treatment and synthetic lethality will be reviewed.

Discovery of First-in-Class Dual PARP and EZH2 Inhibitors for Triple-Negative Breast Cancer with Wild-Type BRCA.

PARP inhibitors have highly significant effects on BRCA mutant cells, allowing targeted therapy of triple-negative breast cancer (TNBC). However, some TBNC patients lack BRCA mutations. Recent studies have shown that EZH2 inhibitors can increase the sensitivity of wild-type BRCA cells to PARP inhibitors. We designed a series of dual PARP and EZH2 inhibitors, and the most promising compound, 5a, showed good inhibitory activity against PARP-1 and EZH2 and good inhibitory effects on MDA-MB-231 (IC50 = 2.63 µM) and MDA-MB-468 (IC50 = 0.41 µM) cells with wild-type BRCA. Compared with that of olaparib, the growth inhibitory activities against these two cell types increased by approximately 15- and 80-fold, respectively, which was even more effective than the combination of olaparib and tazemetostat/GSK126. 5a can induce autophagy death of tumor cells and cause less damage to normal cells. Therefore, 5a, as a first-in-class dual PARP and EZH2 inhibitor, is a potential anticancer drug candidate for the treatment of TNBC.

A novel BRCA1 duplication and new insights on the spectrum and frequency of germline large genomic rearrangements in BRCA1/BRCA2.

Heritable breast cancers account for 5% to 10% of all breast cancers, and monogenic, highly penetrant genes cause them. Around 90% of pathogenic variants in BRCA1 and BRCA2 are observed using gene sequencing, with another 10% identified through gene duplication/deletion analysis, which differs across various communities. In this study, we performed a next-generation sequencing panel and MLPA on 1484 patients to explain the importance of recurrent germline duplications/deletions of BRCA1-2 and their clinical results and determine how often BRCA gene LGRs were seen in people suspected of hereditary breast and ovarian cancer syndrome. The large genomic rearrangements (LGRs) frequency was approximately 1% (14/1484). All 14 mutations were heterozygous and detected in patients with breast cancer. BRCA1 mutations were more predominant (n = 8, 57.1%) than BRCA2 mutations (6, 42.9%). The most common recurrent mutations were BRCA2 exon three and BRCA1 exon 24 (23) deletions. To the best of our knowledge, BRCA1 5'UTR-exon11 duplication has never been reported before. Testing with MLPA is essential to identify patients at high risk. Our data demonstrate that BRCA1-2 LGRs should be considered when ordering genetic testing for individuals with a personal or family history of cancer, particularly breast cancer. Further research could shed light on BRCA1-2 LGRs' unique carcinogenesis roles.

Mutations in BRCA1/2 and Other Panel Genes in Patients With Metastatic Breast Cancer -Association With Patient and Disease Characteristics and Effect on Prognosis.

PURPOSE: Among patients with metastatic breast cancer (mBC), the frequency of germline mutations in cancer susceptibility genes and the clinical relevance of these mutations are unclear. In this study, a prospective cohort of patients with mBC was used to determine mutation rates for breast cancer (BC) predisposition genes, to evaluate the clinical characteristics of patients with mutations, and to assess the influence of mutations on patient outcome. PATIENTS AND METHODS: Germline DNA from 2,595 patients with mBC enrolled in the prospective PRAEGNANT registry was evaluated for mutations in cancer predisposition genes. The frequencies of mutations in known BC predisposition genes were compared with results from a prospective registry of patients with nonmetastatic BC sequenced using the same QIAseq method and with public reference controls. Associations between mutation status and tumor characteristics, progression-free survival, and overall survival were assessed. RESULTS: Germline mutations in 12 established BC predisposition genes (including BRCA1 and BRCA2) were detected in 271 (10.4%) patients. A mutation in BRCA1 or BRCA2 was seen in 129 patients (5.0%). BRCA1 mutation carriers had a higher proportion of brain metastasis (27.1%) compared with nonmutation carriers (12.8%). Mutations were significantly enriched in PRAEGNANT patients with mBC compared with patients with nonmetastatic BC (10.4% v 6.6%, P < .01). Mutations did not significantly modify progression-free survival or overall survival for patients with mBC. CONCLUSION: Multigene panel testing may be considered in all patients with mBC because of the high frequency of germline mutations in BRCA1/2 and other BC predisposition genes. Although the prognosis of mutation carriers and nonmutation carriers with mBC was similar, differences observed in tumor characteristics have implications for treatment and for future studies of targeted therapies.

Next-generation sequencing for identification of actionable gene mutations in intestinal-type sinonasal adenocarcinoma.

Intestinal-type sinonasal adenocarcinoma (ITAC) is a rare tumor carrying poor prognosis and needing new treatment options. The aim of this study was to identify actionable gene mutations that can guide new personalized target-specific therapies in ITAC patients. A series of 48 tumor and 27 corresponding germline DNA samples were analyzed by next generation sequencing using a panel of 120 genes. In total, 223 sequence variants were found in 70 genes. Matched tumor/germline comparison in 27 cases revealed that 57% were in fact germline variants. In 20 of these 27 cases, 58 somatic variants in 33 different genes were identified, the most frequent being PIK3CA (5 cases), APC and ATM (4 cases), and KRAS, NF1, LRP1B and BRCA1 (3 cases). Many of the somatic gene variants affected PI3K, MAPK/ERK, WNT and DNA repair signaling pathways, although not in a mutually exclusive manner. None of the alterations were related to histological ITAC subtype, tumor stage or survival. Our data showed that thorough interpretation of somatic mutations requires sequencing analysis of the corresponding germline DNA. Potentially actionable somatic mutations were found in 20 of 27 cases, 8 of which being biomarkers of FDA-approved targeted therapies. Our data implicate new possibilities for personalized treatment of ITAC patients.

Characterizing TP53 mutations in ovarian carcinomas with and without concurrent BRCA1 or BRCA2 mutations.

OBJECTIVES: Mutations in the TP53 tumor suppressor gene are common in ovarian carcinoma (OC) but their impact on outcomes is controversial. We sought to define the relationship of TP53 mutations to cancer outcomes and their interactions with co-occurrent BRCA1 or BRCA2 (BRCA) mutations, comparing three different TP53 mutation classification schemes. METHODS: We performed next generation sequencing on 393 cases of OC prospectively followed for survival. TP53 mutations were classified according to three schemes termed Structural, Functional, and Hotspot. Mutation distribution was compared between cases with and without BRCA mutations. In a subset of 281 cases of high grade serous carcinoma (HGSC), overall survival was compared using Kaplan-Meier curves, logrank testing, and multivariate Cox regression analysis, both stratified and adjusted for BRCA mutation status. Multivariate logistic regression was used to analyze the effects of TP53 mutation type on platinum resistance. RESULTS: TP53 mutations were identified in 76.8% of the total cohort (n = 302/393) and 87.9% of HGSC (n = 247/281). Cases with BRCA mutations demonstrated significantly higher TP53 mutation frequency overall (n = 84/91, 92.3% vs. n = 218/302, 72.2%, p < 0.001). TP53 mutations were not associated with overall survival, even when stratified by BRCA mutation. TP53 mutations were associated with platinum sensitivity, even after adjusting for BRCA mutation status (OR 0.41, p = 0.048). The choice of TP53 mutation classification scheme was not found to alter any significant outcome. CONCLUSIONS: BRCA mutations significantly co-occur with TP53 mutations. After adjusting for BRCA mutations, TP53 mutations are associated with platinum sensitivity, and this effect is not dependent on TP53 mutation type.

The psychosexual effects of risk-reducing bilateral salpingo-oophorectomy in female BRCA1/2 mutation carriers: A systematic review of qualitative studies.

INTRODUCTION: It is estimated that up to 20% of ovarian cancers have an inherited genetic etiology with the most common being BRCA1/2 mutations. For women with these mutations risk-reducing bilateral salpingo-oophorectomy (RRBSO) to reduce the risk of primary ovarian cancer is often performed, however the surgery results in immediate onset of surgical menopause. AIM: The aim of this systematic review was to explore the psychosexual impacts of risk reducing bilateral salpingo oophorectomy in the published qualitative literature. METHODS: PubMed, Medline, Web of Science and PsycInfo were searched for qualitative papers that looked at the psychosexual impact of RRBSO on individuals who were pre-menopausal at the time of surgery. Studies were quality assessed using Mixed Method Appraisal Tool (MMAT) and Standard for Reporting Qualitative Research (SRQR) checklists and data were extracted. Thematic synthesis of the results was performed. RESULTS: Of 143 papers identified in searching, 5 qualitative papers were identified relating to interviews with 115 women after RRBSO published between 2000 and 2020. The quality of the papers was moderate. Five different themes were identified related to individual experiences with RRBSO: (1) information needs, (2) psychological impact, (3) psychosexual impact, (4) partner support and (5) hormone replacement therapy (HRT). CONCLUSION: Individual experiences of RRBSO were varied and influenced by multiple factors but psychosexual problems were common, often caused significant distress to the women and their partners and were often poorly explained before surgery. Women do not feel adequately prepared for the psychological and sexual side effects of RRBSO. The qualitative data provides invaluable insight into the individual experiences of women and can be used to better help women mitigate the effects of the surgery.

Should the risk for uterine cancer influence decision making for prophylactic hysterectomy in BRCA1/2 mutated patients- a systematic review and meta-analysis.

OBJECTIVE: To study the possible association between uterine cancer and the BRCA1/2 associated cancer syndrome and discuss the implications of such an association on the clinical managment of patients with BRCA1/2 mutations. METHODS: A systematic review and meta-analysis was conducted according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses statement. Study protocol was prospectively registered at PROSPERO International prospective register of systematic reviews (registration number CRD42020193496). Considered for inclusion were studies providing the diagnosis rate of uterine cancer in patients with BRCA1/2 mutations by comparing observed and expected rate according to a known disease incidence. The results were measured by standardized incidence ratio (SIR). The primary outcome was defined as any uterine cancer diagnosis and subgroup analyses were conducted for uterine serous papillary cancer (USPC) specifically and for BRCA1 and BRCA2 mutations separately. RESULTS: 4591 records were identified through database search; eight studies were finally included, comprising 13,098 patients with BRCA1/2 mutations. BRCA1/2 mutated patients were found to have a significantly higher risk for uterine cancer compared to the general population (SIR = 2.22, 95% CI 1.76-2.8, p < 0.001). A higher incidence of USPC was also found in patients with BRCA1/2 mutations (SIR = 17.97, 95% CI 9.89-32.66, p < 0.001), as well as in a separate analysis for BRCA1 (SIR = 2.81, 95% CI 2.09-3.79, p < 0.001) and BRCA2 (SIR = 1.75, 95% CI 1.09-2.80, p < 0.001) mutations. CONCLUSION: Patients who carry a BRCA1/2 mutation are at a significantly higher risk of developing uterine cancer, specifically USPC, supporting that USPC may be a component of the BRCA1/2 syndrome. The decision to perform concurrent hysterectomy at the time of the risk reduction bilateral salpingo -oophorectomy surgery should be considered individually.

A novel signature of two long non-coding RNAs in BRCA mutant ovarian cancer to predict prognosis and efficiency of chemotherapy.

BACKGROUND: In this study we aimed to identify a prognostic signature in BRCA1/2 mutations to predict disease progression and the efficiency of chemotherapy ovarian cancer (OV), the second most common cause of death from gynecologic cancer in women worldwide. METHODS: Univariate Cox proportional-hazards and multivariate Cox regression analyses were used to identifying prognostic factors from data obtained from The Cancer Genome Atlas (TCGA) database. The area under the curve of the receiver operating characteristic curve was assessed, and the sensitivity and specificity of the prediction model were determined. RESULTS: A signature consisting of two long noncoding RNAs(lncRNAs), Z98885.2 and AC011601.1, was selected as the basis for classifying patients into high and low-risk groups (median survival: 7.2 years vs. 2.3 years). The three-year overall survival (OS) rates for the high- and low-risk group were approximately 38 and 100%, respectively. Chemotherapy treatment survival rates indicated that the high-risk group had significantly lower OS rates with adjuvant chemotherapy than the low-risk group. The one-, three-, and five-year OS were 100, 40, and 15% respectively in the high-risk group. The survival rate of the high-risk group declined rapidly after 2 years of OV chemotherapy treatment. Multivariate Cox regression associated with other traditional clinical factors showed that the 2-lncRNA model could be used as an independent OV prognostic factor. Analyses of data from the Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) indicated that these signatures are pivotal to cancer development. CONCLUSION: In conclusion, Z98885.2 and AC011601.1 comprise a novel prognostic signature for OV patients with BRCA1/2 mutations, and can be used to predict prognosis and the efficiency of chemotherapy.

Use of fertility treatments in BRCA1/2 mutation carriers and risk for ovarian and breast cancer: a systematic review.

PURPOSE: Mutations in the genes BRCA1 and BRCA2 represent a significant risk factor for ovarian and breast cancer. With increasing number and success rates, fertility protection and treatment are gaining importance also for BRCA1/2 mutation carriers. However, the effect on primary cancer risk and risk for recurrence remains unclear. This review analyses the published data on fertility treatment and risk of ovarian and breast cancer in BRCA1/2 mutation carriers. METHODS: In this review, we included all relevant articles published in English from 1995 to 2018. Literature was identified through a search on PubMed and Cochrane Library. RESULTS: We identified one retrospective cohort and one case-control study regarding the association of fertility treatments and ovarian cancer risk in BRCA mutation carriers. The studies show no increase in ovarian cancer risk. Furthermore, one case-control study on the association between fertility treatment and breast cancer risk in BRCA mutation carriers and one prospective cohort study on the long-term safety of medication used for fertility preservation in women with a history of breast cancer were identified. One of the studies shows a possible adverse effect for gonadotropin-containing medication. CONCLUSION: Possible increases in cancer risk associated with fertility treatments in BRCA1/2 mutation carriers cannot be excluded at this time. Based on the existing studies, BRCA1/2 mutation carriers should not be generally excluded from fertility treatments. However, they have to be informed about limited data and possible increases in cancer risk.

Endogenous DNA 3' Blocks Are Vulnerabilities for BRCA1 and BRCA2 Deficiency and Are Reversed by the APE2 Nuclease.

The APEX2 gene encodes APE2, a nuclease related to APE1, the apurinic/apyrimidinic endonuclease acting in base excision repair. Loss of APE2 is lethal in cells with mutated BRCA1 or BRCA2, making APE2 a prime target for homologous recombination-defective cancers. However, because the function of APE2 in DNA repair is poorly understood, it is unclear why BRCA-deficient cells require APE2 for viability. Here we present the genetic interaction profiles of APE2, APE1, and TDP1 deficiency coupled to biochemical and structural dissection of APE2. We conclude that the main role of APE2 is to reverse blocked 3' DNA ends, problematic lesions that preclude DNA synthesis. Our work also suggests that TOP1 processing of genomic ribonucleotides is the main source of 3'-blocking lesions relevant to APEX2-BRCA1/2 synthetic lethality. The exquisite sensitivity of BRCA-deficient cells to 3' blocks indicates that they represent a tractable vulnerability in homologous recombination-deficient tumor cells.

Genetic polymorphisms and haplotypes of BRCA1 gene associated with quality of life and survival among patients with non-small-cell lung cancer.

PURPOSE: Quality of life (QoL) and prognosis of lung cancer (LC) patients are poor. Previous studies focused less on the relationship between genetic factors and the QoL of LC patients. The current study is intended to explore the association of SNPs and haplotypes of BRCA1 and the QoL and survival of patients with LC. METHODS: QOL of 291 non-small-cell LC patients was measured by EORTC Core Quality of Life Questionnaire (QLQ-C30) and EORTC Quality of Life Questionnaire-Lung Cancer 13 (QLQ-LC13) before discharge. Three tag SNPs of the BRCA1 gene (rs1799966, rs3737559, rs8067269) were detected using an improved multiplex ligation detection reaction (iMLDR) technique. Haplotype analysis was conducted using the software Haploview 4.2. The patients' survival was followed up every six months until March 2019. RESULTS: rs8067269 was associated with physical functioning (ß = 7.97, p = 0.024) and diarrhea (Odds ratios (OR) 0.32, p = 0.042). rs1799966-rs3737559-rs8067269 haplotype was associated with several domains of QoL, including physical functioning (TCG vs. CCA: ß = 6.21, p = 0.010), worse dyspnea (TCG vs. CTA: OR 2.05, p = 0.031) and peripheral neuropathy (TCG vs. CTA: OR 3.91, p = 0.030). BRCA1 rs1799966 CC genotype, rs8067269 AA genotype and CCA haplotype were associated with longer survival time of LC patients (p < 0.05). CONCLUSION: SNPs and haplotypes of BRCA1 gene were associated with the QoL and survival of patients with LC. Patients with certain genotypes and haplotypes (i.e., rs8067269 AA genotype, or CCA haplotype) had better QoL and prognosis.

p53: 800 million years of evolution and 40 years of discovery.

The evolutionarily conserved p53 protein and its cellular pathways mediate tumour suppression through an informed, regulated and integrated set of responses to environmental perturbations resulting in either cellular death or the maintenance of cellular homeostasis. The p53 and MDM2 proteins form a central hub in this pathway that receives stressful inputs via MDM2 and respond via p53 by informing and altering a great many other pathways and functions in the cell. The MDM2-p53 hub is one of the hubs most highly connected to other signalling pathways in the cell, and this may be why TP53 is the most commonly mutated gene in human cancers. Initial or truncal TP53 gene mutations (the first mutations in a stem cell) are selected for early in cancer development inectodermal and mesodermal-derived tissue-specific stem and progenitor cells and then, following additional mutations, produce tumours from those tissue types. In endodermal-derived tissue-specific stem or progenitor cells, TP53 mutations are functionally selected as late mutations transitioning the mutated cell into a malignant tumour. The order in which oncogenes or tumour suppressor genes are functionally selected for in a stem cell impacts the timing and development of a tumour.

Frequency of mutations in BRCA genes and other candidate genes in high-risk probands or probands with breast or ovarian cancer in the Czech Republic.

Breast cancer is currently the most common form of malignant tumour in womenboth in the Czech Republic and in most countries of the western world, and its incidence is constantly increasing. Many risk factors are known to play a major role in the development of this form of cancer. One of them is genetics, especially the BRCA1/2 genes. A higher risk of ovarian cancer is also associated with these genes. With the development of laboratory diagnostics massive parallel sequencing methods (NGS) are now routinely employed, enabling the detection of other pathogenic sequence variants, or variants of uncertain significance (VUS) not previously detected. Besides the high penetrance BRCA1/2 genes, medium and low penetrant genes also come to the fore. There were 2046 probands examined in the study, men and women, mainly from eastern part of the Czech Republic. These were selected for a genetic examination, after meeting indication criteria (probands from high-risk families or with breast or ovarian cancer). From this group only women, 2033 probands, were selected and were given a genetic examination for the possible presence of patogenic sequence variants in BRCA1/2 genes, or other candidate genes. Analyses were conducted in the laboratory using DHPLC or next generation sequencing. MLPA method is used for large rearrangements in genes. From all examined women 212 mutations were detected. The most mutations (128) were found in the BRCA1 gene (60%). In the BRCA2 gene 71 mutations (34%) were found and 13 more mutations (6%) were detected in another candidate genes (CHEK2, PALB2, ERCC4). The most frequent sequence variant was c.5266dupC in the BRCA1 gene. The results show that 72% of women with a confirmed mutation in the BRCA1 gene and 77.5% of women with the sequence variant BRCA2, already had breast cancer and 16.4% of women with BRCA1 and 7% of women with BRCA2 already had ovarian cancer. Only 21 high risk families used the possibility to be tested and had undergone targeted mutation testing. The study results suggest a reflection of the causes and needs for examination of patients and women predisposed to breast or ovarian cancer.

Exceptional Response to Olaparib in a Patient With Recurrent Ovarian Cancer and an Entire BRCA1 Germline Gene Deletion.

PARP inhibitors are known to be effective in patients with ovarian cancer (OC) and germline mutations in BRCA1 and BRCA2 genes (BRCA mutations). Little is known, however, about any correlation between the deletion size and location of the BRCA mutation and the response to PARP inhibitors. Women with OC commonly undergo genetic testing because the presence of a germline BRCA mutation impacts therapeutic decisions and is important for cancer surveillance in patients and their family members. This report presents a case of a rare entire germline BRCA1 gene deletion and an exceptional response to a PARP inhibitor, olaparib, in a heavily pretreated patient with OC. Her disease course was also remarkable for complete responses to platinum-based chemotherapy and long chemotherapy-free intervals. Interestingly, the deletion of the entire BRCA1 gene was found after previously negative BRCA test results and is associated with a deletion of 6 adjacent genes without known clinical significance. She has remained progression-free and asymptomatic for >3 years on olaparib, with an overall survival of >12 years. We postulate that this unusually favorable response and prolonged overall survival is related to the cancer cells' inability to reverse the entire gene deletion to wild-type (a common mechanism of resistance to PARP inhibition). This case shows the value of genetic testing for patients with OC and highlights the utility of additional testing with previously negative results and limited genetic testing. It also provides insight into a potential mechanism of an exceptional response to PARP inhibition.

Rate of BRCA mutation in patients tested under NCCN genetic testing criteria.

BACKGROUND: BRCA genetic testing is recommended by the National Comprehensive Cancer Network (NCCN) in breast cancer patients who meet specific criteria. Limited data are available on the likelihood of detecting a mutation when these guidelines are followed. METHODS: A retrospective chart review examined patients with breast cancer who underwent BRCA testing based on NCCN guidelines. RESULTS: Twelve (6.0%) of the 199 patients had a deleterious BRCA mutation. Family history of BRCA mutations (50%, p = 0.019), age ≤45 at diagnosis (9.7%, p = 0.034) and meeting ≥3 NCCN criteria (13.3%, p = 0.03) yielded the highest rates of BRCA mutation. Having a family history of BRCA mutation and age ≤45 were associated with increased rate of BRCA mutation on multivariate analysis (OR 14.3, CI 1.2-166.3; OR 11.6, CI 1.2-108.6). CONCLUSION: Select NCCN criteria are associated with higher rates of BRCA mutations. Waiting for genetic testing results to guide surgical management may be warranted in this subset of patients.

Clinical factors associated with prolonged response and survival under olaparib as maintenance therapy in BRCA mutated ovarian cancers.

OBJECTIVE: To investigate clinical factors associated with prolonged progression-free survival (PFS) and overall survival (OS) in relapsing epithelial ovarian cancer (EOC) patients with BRCA mutations and receiving olaparib as maintenance therapy in daily practice. METHODS: Multicenter (8 hospitals) European retrospective study of relapsing EOC patients having germline or somatic mutations of BRCA1/BRCA2 genes and treated with olaparib as maintenance therapy after platinum-based chemotherapy. RESULTS: One hundred and fifteen patients were included. Median age was 54 years. There were 90 BRCA1 carriers, 24 BRCA2 carriers and one patient had germline mutation of BRCA1 and BRCA2. Six patients had somatic mutations (all BRCA1) and 109 had germline mutations. Ninety percent had serous carcinomas and were platinum-sensitive. Following ultimate platinum-based chemotherapy, 69% of the patients had normalization of CA-125 levels and 87% had RECIST objective responses, either partial (53%) or complete (34%). After a median follow-up of 21 months, median PFS was 12.7 months and median OS was 35.4 months. In multivariate analysis, factors associated with prolonged PFS under olaparib were: platinum-free interval (PFI) ≥ 12 months, RECIST complete response (CR) or partial response (PR) and normalization of CA-125 upon ultimate platinum-based chemotherapy. Factors associated with prolonged OS were PFI ≥ 12 months, CR and normalization of CA-125. CONCLUSIONS: Platinum-free interval ≥ 12 months, complete response and normalized CA-125 levels after ultimate platinum-based chemotherapy are associated with prolonged PFS and OS in relapsing BRCA1/BRCA2 mutated ovarian cancer patients who received olaparib as maintenance therapy.

Effect of variation in miRNA-binding site (rs8176318) of the BRCA1 gene in breast cancer patients

Background/aim: A variation in the 3 prime untranslated regions (3'-UTRs) affects the binding of microRNA (miRNA) to the breast cancer (BC) susceptibility gene 1 (BRCA1) gene, and thus regulate its expression. In this study, the consequences of a variation in the miRNA-binding site (rs8176318G>T) in the 3'-UTRs of BRCA1 and its association with the risk of BC were investigated. Materials and methods: The selected variation (rs8176318G>T) was genotyped in BC patients (n = 300) and healthy controls (n = 300) using allele-specific polymerase chain reaction (PCR) [tetra-primer amplification refractory mutation system-PCR (T-ARMS-PCR)]. The results of the T-ARMS-PCR were further confirmed by Sanger sequencing through a random selection of 10% previously analyzed samples by T-ARMS-PCR. Association of this variation with BC was tested by calculating the odds ratio (OR) (at 95% CI) and χ2-value using 4 different genetic models (codominant, dominant, recessive, and additive models). Results: Using Fisher's exact test, a significant association between variant rs8176318 (G>T) and BC was found in codominant [χ2-value = 15.68, df: 2 P < 0.0004], dominant [OR = 1.557 (1.082­2.241), P <0.0213], recessive [OR = 0.474 (0.3204­0.7017), P = 0.0002] and additive models [OR = 1.609 (1.282­2.018), P < 0.0001]. Conclusion: It was therefore concluded that there is a significant association between rs8176318 and BC risk in a case-control study in a Pakistani population. Furthermore, an association study using a large sample size is required to further verify these findings.