Mutations In BRCA1 Genes Research Articles

Prevalence of homologous recombination biomarkers in multiple tumor types: an observational study.

Aim: To determine the prevalence of deleterious mutations in BRCA1 and BRCA2 and in 13 genes involved in homologous recombination repair (HRR), the prevalence of genomic loss of heterozygosity and the allelic and hereditary status of BRCA1, BRCA2 and other HRR gene mutations in multiple solid tumor types. Patients & methods: This was a retrospective observational study of patients with an advanced/metastatic diagnosis in one of 15 solid tumor types, who were identified in a real-world clinico-genomic database. Results: Tumor tissue samples from 9457 patients were analyzed, among which 4.7% had known or suspected deleterious BRCA1/2 mutations. The prevalence (range) of mutations in HRR genes was 13.6% (2.4%-26.0%) and genomic loss of heterozygosity ≥16% was 20.6% (2.6-34.4%) across all tumor types. Conclusion: The prevalence of mutations varied significantly depending on the type of tumor.

Overcoming Chemoresistance in Cancer: The Promise of Crizotinib.

Chemoresistance is a major obstacle in cancer treatment, often leading to disease progression and poor outcomes. It arises through various mechanisms such as genetic mutations, drug efflux pumps, enhanced DNA repair, and changes in the tumor microenvironment. These processes allow cancer cells to survive despite chemotherapy, underscoring the need for new strategies to overcome resistance and improve treatment efficacy. Crizotinib, a first-generation multi-target kinase inhibitor, is approved by the FDA for the treatment of ALK-positive or ROS1-positive non-small cell lung cancer (NSCLC), refractory inflammatory (ALK)-positive myofibroblastic tumors (IMTs) and relapsed/refractory ALK-positive anaplastic large cell lymphoma (ALCL). Crizotinib exists in two enantiomeric forms: (R)-crizotinib and its mirror image, (S)-crizotinib. It is assumed that the R-isomer is responsible for the carrying out various processes reviewed here The S-isomer, on the other hand, shows a strong inhibition of MTH1, an enzyme important for DNA repair mechanisms. Studies have shown that crizotinib is an effective multi-kinase inhibitor targeting various kinases such as c-Met, native/T315I Bcr/Abl, and JAK2. Its mechanism of action involves the competitive inhibition of ATP binding and allosteric inhibition, particularly at Bcr/Abl. Crizotinib showed synergistic effects when combined with the poly ADP ribose polymerase inhibitor (PARP), especially in ovarian cancer harboring BRCA gene mutations. In addition, crizotinib targets a critical vulnerability in many p53-mutated cancers. Unlike its wild-type counterpart, the p53 mutant promotes cancer cell survival. Crizotinib can cause the degradation of the p53 mutant, sensitizing these cancer cells to DNA-damaging substances and triggering apoptosis. Interestingly, other reports demonstrated that crizotinib exhibits anti-bacterial activity, targeting Gram-positive bacteria. Also, it is active against drug-resistant strains. In summary, crizotinib exerts anti-tumor effects through several mechanisms, including the inhibition of kinases and the restoration of drug sensitivity. The potential of crizotinib in combination therapies is emphasized, particularly in cancers with a high prevalence of the p53 mutant, such as triple-negative breast cancer (TNBC) and high-grade serous ovarian cancer (HGSOC).

O-061 Ovarian cancer and fertility - current understanding

Abstract Introduction Ovarian cancer is a significant health concern worldwide and is the leading cause of death from gynecologic malignancies. While fertility preservation is essential for many young women diagnosed with cancer, concerns have been raised regarding the potential impact of fertility treatments on the risk of ovarian cancer development. 1. Ovarian Cancer Risk Factors Ovarian cancer is a multifactorial disease with various risk factors contributing to its development. A woman has a risk of 1 in 78 of having ovarian cancer in her life time, risk factors include: • Age: Ovarian cancer risk increases with age, with the highest incidence observed in women over 50 years old. About 12.1% of Ovarian Cancer patients are younger than 44 years old. • Family History: Women with a family history of ovarian or breast cancer, especially first-degree relatives, have an increased risk. • BRCA Mutations: Inherited mutations in BRCA1 and BRCA2 genes significantly elevate the risk of ovarian cancer. • Reproductive Factors: Factors such as nulliparity, early menarche, late menopause, and infertility have been associated with an increased risk of ovarian cancer. 2. Fertility Treatments and Ovarian Cancer Risk Understanding the mechanisms underlying ovarian cancer development is crucial for assessing the potential impact of fertility treatments : • Ovulation Hypothesis: The repeated ovulation theory suggests that each ovulatory cycle increases the risk of DNA damage to ovarian epithelial cells, potentially leading to cancer development. The use of fertility drugs to stimulate ovulation, such as clomiphene citrate and gonadotropins, has been studied , the early studies suggested a potential increased risk, more recent evidence has been conflicting, with some studies reporting no association. • In Vitro Fertilization (IVF): Several large-scale studies have investigated the relationship between IVF and ovarian cancer risk found no significant increase in ovarian cancer risk . • Hormonal Influence: Fertility drugs alter hormonal levels, particularly estrogen and progesterone, which may influence ovarian cancer risk. • Selection Bias: Some studies have suggested that the ovarian cancer risk may be confounded by underlying infertility factors rather than the treatments themselves. 3. Clinical Implications and Recommendations • Individual Risk Assessment: Clinicians should assess each patient's individual risk factors for ovarian cancer, including age, family history, and reproductive history, before initiating fertility treatments. • Informed Consent: Patients should be provided with comprehensive information regarding the potential risks and benefits of fertility treatments • Regular Surveillance: Women undergoing fertility treatments should receive regular gynecologic screenings and follow-up care to monitor for any signs or symptoms of ovarian cancer. • Shared Decision Making: Shared decision making between patients and healthcare providers is essential to ensure that treatment decisions align with patients' preferences and values. 4. Fertility Preservation Options • Most therapeutic options for Ovarian Cancer cause infertility, either by premature ovarian failure caused by cytotoxic agents in chemotherapy or surgical approaches that include unilateral or bilateral oophorectomy • In ovarian cancer patients, Oocyte cryopreservation is still the best option and the only one established along with embryo cryopreservation. Fertility preservation surgery can be suggested depending on histology, stage of disease and pre-existing ovarian reserve. • Ovarian tissue cryopreservation will not be an option as long as the risk of reseeding cancer cells is not fully eliminated. 5. Future Directions Advancements in molecular biology and genetics may shed light on the underlying mechanisms of ovarian cancer development and its potential association with fertility treatments. The artificial ovary and in vitro maturation of oocytes is a very attractive option in these patients, but further milestones have to be achieved

P-376 Letrozole to minimise exposure to elevated serum estradiol during superovulation for breast cancer patients prior to chemotherapy. Real world experience from a statewide oncofertility service

Abstract Study question How effective is co-treatment with letrozole in supressing peak E2 in a real world setting? Summary answer We observed greater than anticipated supra-physiological serum estadiol concentrations in our cohort. What is known already Breast cancer occurs frequently in women of reproductive age, many of whom request oocyte or embryo cryopreservation before chemo/radiotherapy. Oncofertility treatment requires superovulation with resultant elevation of serum estradiol above concentrations seen physiologically. In order to avoid possible stimulation of estrogen receptor positive breast cancers, co-administration of letrozole is frequently recommended. A 67% lower mean serum estradiol in a letrozole treated group compared with an untreated superovulated comparison group has been reported in the literature, suggesting a protective mechanism. Peak E2 concentration across 4 cohorts of patients co-treated with letrozole has been reported to be 103 – 2350 (mean 564). Study design, size, duration We performed a retrospective cohort study of women referred for fertility preservation following diagnosis of breast cancer to the Fertility Research Centre at The Royal Hospital for Women, Sydney between Jan 2020 and Jan 2024. Women were identified from hospital outpatient paper and electronic medical records. 145 new referrals were received by our centre, with 88 patients undergoing 107 cycles. Participants/materials, setting, methods 145 women aged between 19 and 44 with newly diagnosed breast cancer were referred to our Statewide, multidisciplinary, public oncofertility service for consideration of treatment and review at our fertility multidisciplinary team meeting. Our oncofertility database and outpatient clinical records were used to identify new referrals to the service. Electronic and paper medical records including the ART database were used to obtain cycle information, blood results and demographic information Main results and the role of chance Peak estradiol concentrations (pMol/L) 35% of cycles resulted in peak E2 > 2000. 11% of cycles resulted in peak E2 > 4000 and 2% of cycles resulted in peak E2 > 7000. We calculated a mean E2 of 1837. The mean anti-mullerian hormone was 20.3 pMol/L and mean antral follicle count 19.7. The mean BMI was 24.7. The average stimulation length was 13 days (7-16 days) with an average cumulative gonadotrophin dose of 2769 IU. Average number of MII oocytes per cycle was 7.2. 16 % of patients elected to preserve embryos. The fertilisation rate was 50%, with 61% of fertilised eggs resulting in frozen blastocytes. There have been 2 pregnancies and one live birth to date. 32% of cycles had a germline genetic result prior to OPU, with 20% having a positive BRCA gene mutation. Breast cancer hormone status 56% were Estrogen Receptor positive. 38 % were Progesterone Receptor positive, 18% were HER2 positive, 24% were hormone receptor negative Complications 5% of cycles were cancelled prior to OPU, 8% of cycles resulted in no oocyte or embryo available for freezing. 3% of cycles were reviewed for OHSS symptoms with 2 confirmed cases of OHSS secondary to administration of Zoladex <24hrs following OPU. Limitations, reasons for caution This is a retrospective cohort study in a single academic centre. Our current study duration is too short to permit determination of recurrence rates of breast cancer in the letrozole treated cohort. Wider implications of the findings The impact of short, transient elevation of circulating estradiol during superovulation is uncertain, however it is prudent to try to minimise exposure of ER positive breast cancers to estrogen. Alternative strategies for limiting this phenomenon should be explored, more evidence is needed on oncological and fertility outcomes in this population. Trial registration number N/A

Vaginal assisted NOTES hysterectomy in The Netherlands; A prospective cohort study

ObjectivesVaginal assisted Natural Orifice Transluminal Endoscopic Surgery (NOTES) combines the benefits of vaginal and endoscopic surgery. This study presents the results of the first vaginal assisted NOTES hysterectomies (VANH) in The Netherlands. Study designA prospective cohort study was performed in two non-academic teaching hospitals in The Netherlands. Data was collected from patients who underwent a VANH for benign indications between August 2019 and April 2023. Baseline characteristics and data of intra- and postoperative surgical outcomes were recorded and analysed. The VANHs were performed by four experienced vaginal and endoscopic gynaecological surgeons. ResultsA total of 200 patients underwent a VANH. Indications were dysfunctional menstrual bleeding (61 %; n = 122), abnormal cervical cytology (15.5 %; n = 31), abdominal pain (11.5 %; n = 23), post ablation/sterilization pain syndrome (3.5 %; n = 7), uterine fibroids (5.0 %; n = 10), atypical endometrial hyperplasia (2.5 %; n = 5) and Lynch or BRCA gene mutation carriers (1.0 %, n = 2). The mean surgical time was 61.4 min ( ± 22.8 min) with a mean blood loss of 88 mL ( ± 89 mL) and a mean uterine weight of 150 g ( ± 112 g). In 2.0 % (n = 4) of the cases a conversion was necessary. Same day discharge (SDD) was feasible in 80.2 % (n = 105) of the patients planned in day-care. In 2.0 % (n = 4) an intra-operative complication and in 9.0 % (n = 18) a post-operative complication occurred. ConclusionThis study shows vNOTES to be a safe and feasible surgical technique and can be safely implemented with appropriate patient selection and skilled surgeons. It highlights the importance of surgeon awareness of the challenges inherent in the initial stages of the implementation of a new surgical technique when performing their first vNOTES procedures. Additional randomized clinical trials are needed to show superiority of vNOTES compared to traditional surgery.

Knowledge of BRCA gene among young Pakistani adults: A short report.

A total of 271 young Pakistani adults responded to a selfdesigned multiple choice-based questionnaire (α = 0.83) which was then used to assess the levels of knowledge regarding breast cancer susceptibility (BRCA) gene mutation. Overall knowledge levels were assessed using the sum score of each response; any possible significance between knowledge scores and educational backgrounds as well as gender were also tested. The results show that 161 (63.9%) of the sample population had awareness about BRCA gene mutation. Knowledge scores were comparable across both groups (medical and non-medical educational backgrounds) with 20 (13.8%) of medical and 14 (13.5%) of non-medical respondents demonstrating a high level of knowledge about the BRCA gene mutation and its testing. Neither gender nor educational background had a significant influence on knowledge scores. The results from this report suggest that awareness regarding BRCA gene was adequate, while knowledge levels were noted to be poor among the sample population.

Molecular insights into TP53 mutation (p. Arg267Trp) and its connection to Choroid Plexus Carcinomas and Li-Fraumeni Syndrome.

Choroid plexus carcinomas (CPCs) are rare malignant tumors primarily affecting pediatric patients and often co-occur with Li-Fraumeni Syndrome (LFS), an inherited predisposition to early-onset malignancies in multiple organ systems. LFS is closely linked to TP53 mutations, with germline TP53 gene mutations present in approximately 75% of Li-Fraumeni syndrome families and 25% of Li-Fraumeni-like syndrome families. Individuals with TP53 mutations also have an elevated probability of carrying mutations in BRCA1 and BRCA2 genes. To investigate the structural and functional implications of the TP53: 799C > T, p. (Arg267Trp) missense mutation, initially identified in a Saudi family, and understand its impact on TP53 functionality and related intermolecular interactions. Computational analyses were conducted to examine the structural modifications resulting from the TP53: 799C > T, p. (Arg267Trp) mutation. These analyses focused on the mutation's impact on hydrogen bonding, ionic interactions, and the specific interaction with Cell Cycle and Apoptosis Regulator 2 (CCAR2), as annotated in UniProt. The study revealed that the native Arg267 residue is critical for a salt bridge interaction with glutamic acid at position 258. The mutation-induced charge alteration has the potential to disrupt this ionic bonding. Additionally, the mutation is located within an amino acid region crucial for interaction with CCAR2. The altered properties of the amino acid within this domain may affect its functionality and disrupt this interaction, thereby impacting the regulation of catalytic enzyme activity. Our findings highlight the intricate intermolecular interactions governing TP53 functionality. The TP53: 799C > T, p. (Arg267Trp) mutation causes structural modifications that potentially disrupt critical ionic bonds and protein interactions, offering valuable insights for the development of targeted mutants with distinct functional attributes. These insights could inform therapeutic strategies for conditions associated with TP53 mutations.

The prevalence of RCTs in PARP and immune-checkpoint blockade combination trials: An appraisal of clinical evidence generation in oncology.

e23006 Background: PARP-inhibitors were developed to promote lethal genomic instability in cancers with homologous recombination repair (HRR) defects, ultimately receiving approval for patients with BRCA gene mutations. At the tumor microenvironment, DNA instability is linked to higher expression of immune activating signals such as PDL1. PDL1 is one of the primary targets for immune-checkpoint inhibitors (ICIs), receiving approval for numerous cancer types. In-vitro studies support mechanisms of possible synergy for PARP and ICIs in combination. Despite both therapy classes being available to oncologists for nearly a decade, the clinical benefit for these agents together remains unclear. Our study aims to appraise the global clinical trial landscape for trials testing combination PARP and PD1/PDL1 regimens. Methods: Search terms for all known approved or unapproved PD1/PDL1 and PARP inhibitors associated with trials registered on the National Library of Medicine’s website, clinicaltrials.gov, were included in the cohort as long as one interventional arm administered both agents. Qualitative and quantitative trial data features were collected from the Cancer Research Institute (CRI) Immuno-Oncology Intelligence Database and complemented with manually sourced information from trial registries and publications. Contribution of Effect (COE) was defined as trials with two or more arms that compare our combination regimen of interest to PARP or an ICI alone. The presence of randomization, eligibility for randomized-controlled trial (RCT) status as well as COE was determined by three reviewers separately with disagreements settled by committee decision. Results: In total, we found 188 clinical trials that enrolled 39,268 patients. A minority of 17 trials were phase I not considered as RCTs, leaving 37,827 patients across 171 trials for enrollment in phase II trials and beyond. Of these 171 trials, 80 (47 %) were single-arm studies without active comparator. Forty-nine (29%) used randomized assortment, 40 (23%) met criteria for an RCT and 33 (19%) met criteria for RCT with COE. In total, these 33 trials enrolled 14,803 patients. Of the 33, 17 (10%) enrolled patients with cancers that are approved for PARP blockade by the FDA and 11 (6%) employed genetic testing for HRR defects. Sponsorship ranged from 16 trials by industry, 6 by cooperative oncology group, 6 by academic institutions and 5 by the National Cancer Institute. Conclusions: Our study results highlight that the global clinical trial apparatus directs significant resources and patients towards trials with lower standards of evidence generation. Across sponsor types, there was a considerable number of trials that met the rigor of an RCT with COE. These findings show both promise and areas of improvement within the trial landscape to generate evidence relevant to the use of PARP and ICIs in combination.

Preoperative Expectations of Women Undergoing Breast Reconstruction Surgery.

The study investigated the expectations of patients undergoing immediate breast reconstruction after mastectomy, considering factors such as the cause for mastectomy (cancer versus prophylactic due BRCA1 or BRCA2 gene mutations), age, marital status, and education. The study had a cross-sectional design. Eligible patients at Oslo University Hospital received a link to the BREAST-Q Expectations questionnaire, which they filled out before surgery from 2019 to 2022. One hundred forty-six patients completed the questionnaire (79.8% response rate). The mean age was 46.6 years, and the majority (95.1%) were undergoing reconstruction with implants. Most patients (86.9%) wanted to be involved in the decision-making. The highest expectation was for breast appearance and the lowest for sensation after surgery. Patients not diagnosed with cancer (n = 27) before surgery expected significantly more pain after surgery compared with patients diagnosed with cancer (P = 0.016). Patients 40 years or younger had higher expectation of pain after surgery than patients 41 years or older, 73.2 versus 54.2, P < 0.001, respectively. After 10 years, 26.7% of the patients expected that further reconstruction procedures might be necessary. Our study's results regarding patient's expectations with breast reconstruction, as assessed using the BREAST-Q Expectations module, align with previous research in terms of overall trends. However, our study provides a more nuanced understanding by exploring variations within different patient subgroups. These differences emphasize the need for personalized preoperative counseling and support to align patient's expectations with realistic outcomes.

Association of childhood trauma with choice of bilateral mastectomy for the treatment of unilateral breast cancer.

e24096 Background: Patients are increasingly choosing bilateral mastectomy (BMX) for the treatment of primary breast cancer (BC) despite minimal survival benefits and potential for adverse medical and psychosocial consequences. Exposure to childhood trauma is associated with dysregulation of stress response systems, threat perception alterations, increased risk-taking behaviors, and body dissatisfaction. We examined childhood trauma in relation to treatment decision-making in adulthood within a sample of breast cancer patients undergoing either BMX or more conservative BC treatment. Methods: Secondary analyses of a case-control study of the neurobiological and affective determinants of BMX choice were conducted. Cross-sectional data from the baseline survey were analyzed. Participants were recruited via institutional clinic practices, social media, and patient advocacy groups. Patients completed a medical status questionnaire and the Childhood Trauma Questionnaire (CTQ). Chi-square and Mann-Whitney U tests examined differences in treatment decision-making by childhood trauma exposure and type. Results: The sample included 137 patients with unilateral stages 0-III BC (mean age 49.2; SD = 11.2; 76.6% White; 10.9% Hispanic/Latina; 68.6% married). Seven tested positive for a BRCA gene mutation. Patients were divided between BMX (n = 66) and non-BMX (n = 71) treatment groups. On average, patients in the non-BMX group reported higher levels of childhood trauma severity (Median = 7; IQR = 0-12.5) compared to patients in the BMX group (Median = 4; IQR = 0-11.75; Mann Whitney U = 4728; small effect size; SRD = -0.11; p = .26). Patients who reported a major parental upheaval (e.g., divorce, separation) were significantly more likely to pursue non-BMX compared to BMX (small effect size; SRD = -.16; p = .047). Patients who reported any uncategorized major upheaval were more likely to choose non-BMX than BMX (small effect size; SRD = -.14), but group differences did not reach significance (p = .093) . No other statistically significant relationships were observed. Conclusions: Contrary to hypotheses, preliminary results suggest BC patients who were exposed to traumatic events in childhood may be more likely to elect conservative BC surgical treatments. Trauma-related hypervigilance to threats may cause patients to exercise more caution regarding treatment choice. More research exploring the effects of adverse childhood experiences in the BC population is warranted. [Table: see text]

Predicting pathological response in early-stage triple-negative breast cancer: Exploring the role of BRCA gene mutations—A retrospective single-institution study.

e12656 Background: Triple-negative breast cancer (TNBC) is a highly aggressive subtype of breast cancer, constituting approximately 15-20% of all breast cancer cases. While less than 10% of all breast cancer patients harbor BRCA1/2 mutations, ~20% of TNBC patients carry these mutations. Notably, at least one-third of BRCA1 carriers develop TNBC. This study aimed to investigate the association between BRCA mutation status and pathological response (PR) in early-stage TNBC patients, specifically, the impact of BRCA positivity on achieving pathological complete response (pCR), and identify other potential predictors of PR. Methods: We conducted a retrospective cohort study of patients with early-stage (Stage I-III) triple-negative breast cancer diagnosed and treated at our institution between January 2012 and June 2022, following Institutional Review Board (IRB) approval. Patients were identified from our Institutional Cancer Registry based on complete data availability (including other inclusion criteria) excluding patients who did not receive neoadjuvant chemotherapy. Data on demographics, tumor characteristics, treatment regimens, and pathological response (assessed according to [specified criteria]) were extracted from the charts. Results: Out of 228 patients diagnosed with early-stage triple-negative breast cancer, 54.6% had no genetic mutations, while 7.9%, 4.9%, and 8.4% harbored BRCA1, BRCA2, and other mutations, respectively. Notably, 23.4% did not receive genetic counseling or testing at our institution. Patients with BRCA2 mutations had a 100% pathological response rate, of which 57.14% had pCR, compared to 85.7% for BRCA1, of which 71.43% had pCR. Furthermore, 93.8% of patients with other genetic mutations had pathological response, of which 56.25% had pCR, as compared to 68.42% in non-mutated cases of which 26.7% had pCR ( P=0.038). Analysis of other variables revealed no significant impact of age, BMI, performance status, or neoadjuvant chemotherapy regimen on pathological response. Conclusions: This retrospective study suggests a trend towards higher complete pathological responses in early-stage triple-negative breast cancer patients with BRCA and other genetic mutations compared to those without. These findings were statistically significant, indicating a potential clinical trend that specific genetic mutations may be associated with improved response to neoadjuvant chemotherapy in early-stage triple-negative breast cancer. Further research is needed to confirm these findings and guide the development of personalized treatment strategies based on a patient's genetic profile. Additionally, our findings highlight the importance of genetic testing for all patients with early-stage triple-negative breast cancer, regardless of age or family history.

Positivity of BRCA 1 &amp; 2 Mutations in Ovarian Cancer

Aim: Ovarian cancer is a significant gynecological malignancy, with mutations in BRCA1 and BRCA2 genes contributing to its development and progression. Methods: This descriptive cross-sectional study was conducted at JPMC Hospital, Karachi, over six months. It involved 159 women aged 18 to 75 years with histopathologically confirmed ovarian cancer. The study employed non-probability consecutive sampling and next-generation sequencing to identify BRCA mutations. Results: The study found a low percentage of participants with a family history of ovarian cancer, a few identified with BRCA1 mutations, none with BRCA2 alone, and a minor proportion with mutations in both genes, suggesting a higher incidence of non-mutation- associated ovarian cancer. Conclusion: The findings indicate a relatively low rate of BRCA1 and BRCA2 variations within those suffering from ovarian cancer in Pakistan, pointing to the need for further research to understand the genetic underpinning of ovarian carcinoma in this population and to develop targeted prevention and treatment strategies. Keywords: BRCA mutations, ovarian cancer, genetic testing, Pakistan, prevalence, cross- sectional study.

ОСОБЕННОСТИ ТАКТИКИ ВЕДЕНИЯ ПРИ НОСИТЕЛЬСТВЕ МУТАЦИЙ В ГЕНАХ BRCA У ЖЕНЩИН

The aim of the study is to study the features of management tactics in the case of BRCA gene mutations in women using the example of a clinical case. Risk-reducing salpingo-oophrectomy is usually offered to women with mutations in BRCA1, BRCA2, or both of them, because, according to research, it improves overall survival and reduces the number of deaths from serous cancer and breast cancer. In this case, a comprehensive examination was carried out in a timely manner in a patient with breast cancer, including a medical and genetic one, which made it possible to identify the presence of a highly oncogenic type of mutation in the BRCA 2 gene. According to large–scale studies, women carrying this type of mutation represent a risk group for developing bilateral breast cancer, as well as ovarian cancer. In addition, carriers of a mutation in the BRCA2 gene are threatened by the occurrence of pancreatic and biliary tract cancers, stomach, fallopian tubes and skin melanoma. Carrying out preventive mastectomy and bilateral ovariectomy in such patients reduces their risk of malignant neoplasms. Therefore, the patient's complex therapy included these stages of surgical treatment. In addition, the detection of such a form of breast cancer associated with mutations in the BRCA genes makes it possible to expand the range of diagnostic search for malignant neoplasms, including in-depth examination of both the patient herself and her closest relatives. Such tactics of management of this group of patients allows them to avoid the occurrence of repeated cases of malignant neoplasms associated with the carriage of mutations in the BRCA genes with timely preventive examination and follow-up.

Abstract PO5-02-14: Clinical-pathological determinant factors to choose between four or six cycles of adjuvant chemotherapy with docetaxel/cyclophosphamide (TC) in a retrospective real-world cohort of HER2-negative breast cancer patients

Abstract Introduction: The long-term severe adverse events associated with anthracyclines, including irreversible cardiotoxicity, myelodysplastic syndromes, and therapy-related leukemias, led researchers to question the risk-benefit of anthracycline-based chemotherapy regimens, especially for patients without axillary lymph node involvement, leading to an increasing trend to omit anthracyclines in adjuvant treatment. Docetaxel plus cyclophosphamide (TC) has replaced doxorubicin plus cyclophosphamide (AC) for lower-risk patients that need adjuvant chemotherapy. However, the optimal number of cycles of adjuvant in patients with node-positive or node-negative breast cancer is currently unknown. Methods: We performed a retrospective cohort study of patients with HER2-negative breast cancer, stage I to III, that received adjuvant docetaxel and cyclophosphamide (TC) for four or six cycles, treated from January 2010 to December 2021. Patients were included from four cancer institutions, both private and public, located in the South, Southeast, and Northeast of Brazil. Objectives: To investigate the clinical-pathological characteristics and survival of earlystage HER2-negative breast cancer patients who received four (TC4) or six cycles (TC6) of adjuvant docetaxel and cyclophosphamide (TC). Results: We collected data from six hundred and ninety-eight patients, 98.7% were female with an average age of 52 years, 51.9% were postmenopausal, 14.6% BRCA gene mutation, 66% had some comorbidity, and only 8.4% were not candidates for anthracyclines. Two hundred and twenty-five patients had public and 473 private health insurance. About 13.2% of the patients were hormone receptor negative (HR-) and 86.8% hormone receptor positive (HR+), 57.4% breast-conserving surgery and 77.7% sentinel lymph node (SL). Five hundred sixty-four (80.8%) patients received TC4 and 134 (19.2%) TC6. We observed that patients who received TC 6 had unfavorable prognostic factors such as: (TC4 vs TC6) previous breast cancer (8.7% vs 16.3%) (p=0.002), invasive ductal carcinoma (IDC) (73.4 vs 86.7%) (p=0.009), histological grade 3 (HG3) (34.9 vs 42.9%) (p= 0,085) conservative surgery (59.4% vs 53%) (p=0144), SL (80.9% vs 62.2%) (p =0.001), Lymph node positive (15% vs 42.3%) (p=0.001), pathological stage II (37.5% vs 50%) (p=0.001).Treatment completion rates were 96.5% and 84.3% for TC4 and TC6, respectively (p=0,02). The incidence of grade 3 or higher toxicity with TC6 (14% vs 21.1%; p= 0,043). Febrile neutropenia was observed in 6.7% of both groups. Grade 3 or higher neuropathy was most common with TC6 (2.2% vs 10.3%; p=0,163). Permanent treatment discontinuation was more frequent in the TC6 group (3.4% vs. 9.8%; p=0,004), as well as late toxicity (3.4% vs. 9.2%; p=0,004). Ninety-four percent of the patients completed the proposed cycles of chemotherapy, 72% received adjuvant radiotherapy and 85.4% received adjuvant hormone therapy, with 42% of these receiving an aromatase inhibitor for 5 years. The median follow-up of the entire cohort was 61 months. There was no difference in the 5-year DFS (77.5% vs. 64.7%; p=0.159) or the 5-year OS (89.5% vs. 70.5%; p= 0,06) between patients treated with TC4 and TC6. Conclusion: TC6 was commonly used for patients with unfavorable prognostic factors as history of previous breast cancer, (IDC), HG III, lymph node positive and stage II. Patients who received TC6 had less chance of completing the treatment and more severe toxicity, especially late peripheral neuropathy. There was no difference in DFS or OS. Citation Format: Mila Kraychete, Marcelle Cesca, Guilherme Almeida, Leonardo Santana, Luciana Leite, Solange M. Sanches, Vladmir Cordeiro de Lima, Rafaela Pirolli, Rafael Manea, Felipe Kaneta, Jean Coutinho, Lucas Vian, Waires Zeviani, Marcio Reis, Luciana Landeiro, Clarissa Mathias, Geila Nunez, Tamara Santana, Monique Tavares. Clinical-pathological determinant factors to choose between four or six cycles of adjuvant chemotherapy with docetaxel/cyclophosphamide (TC) in a retrospective real-world cohort of HER2-negative breast cancer patients [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO5-02-14.

Germline mutations in BRCA1 and BRCA2 among Brazilian women with ovarian cancer treated in the Public Health System

BackgroundGermline mutations in BRCA1 and BRCA2 genes are among the main causes of hereditary ovarian cancer. Identifying these mutations may reduce cancer risk, facilitate early detection, and enable personalized treatment. However, genetic testing is limited in the Brazilian Public Health System, and data regarding germline mutations in many regions are scarce. Therefore, the study aimed to investigate the prevalence of germline mutations in BRCA1 and BRCA2 in women with ovarian cancer treated in the Public Health System in Pernambuco, Brazil.MethodsA cross-sectional study was conducted in the Hereditary Cancer Program from two reference oncological centers in Pernambuco. Women (n = 45) with high-grade serous ovarian cancer underwent genetic counseling and DNA sequencing for BRCA1 and BRCA2 genes.ResultsThe prevalence of deleterious mutations in the BRCA1 and BRCA2 genes was 33%. Of the 15 germline mutations found, 13 were in BRCA1 and 2 in BRCA2; two mutations of unknown clinical significance were also found in BRCA2. Mutations c.5266dupC and c.2215 A > T were the most frequent; each was mutation observed in three patients. Additionally, the mutations c.7645dupT and c.921dupT were reported for the first time.ConclusionOne in three women showed a pathogenic mutation, demonstrating a significant prevalence of germline mutations in this sample. Additionally, the small sample revealed an interesting number of mutations, indicating the need to explore more regions of the country.

Abstract LB273: Pharmacological synthetic lethality by co-inhibition of PARP and HDAC enzymes

Abstract Introduction: Inhibition of poly(ADP-ribose) polymerase (PARP) induces synthetic lethality in cells exhibiting defects in homologous repair (HR) pathways, such as BRCA1 and BRCA2-mutated breast or ovarian cancers, and 4 different PARP inhibitors (PARPi) are currently approved by the FDA. While HR-deficient cancers usually respond well to single agent PARPi, HR-proficient cancers are generally less sensitive to the treatment. Acquired resistance to PARPi due to activating mutations in BRCA genes are also not uncommon. In this work, we have examined strategies for enhancing PARPi activity in a HR-proficient context and identified histone deacetylases (HDACs) as targets for pharmacological synthetic lethality in the context of PARPi. Materials and methods: PARP1 and PARP2 activity were measured using Trevigen Universal Colorimetric PARP Assay Kit, BPS Bioscience PARP2 Colorimetric PARP2 Assay Kit, and PARylation assay. HDAC activity was measured using HeLa cell nuclear extracts and a fluorogenic peptide-based biochemical assay. Cell survival EC50 were determined using CellTiter Glo viability assay. Cell cycle analysis was performed by flow cytometry with propidium iodide staining. DNA damage was investigated by immunoblotting and immunofluorescence using gamma-H2AX antibodies, and comet assays for confirmation of double-strand breaks. Spheroid assays were performed using the Incucyte® S3 spheroid analysis module. In vivo metastasis formations were examined using the pulmonary metastasis assay (PuMA). Results and discussion: Combinations of PARP and HDAC inhibitors in HR-proficient tumor cells demonstrated that HDACi could enhance the efficacy of PARPi in vitro. This was associated with increased acute and sustained DNA-damage distinct cell cycle profiles showing activity in both S- and G2/M-phases. Importantly, dual single-molecule PARP-HDAC inhibitors showed potent inhibition of PARP1 and PARP2 activity and PAR synthesis, comparable to olaparib, as well as inhibition of HDAC with IC50 values in the low µM range. Dual PARP-HDAC inhibition decreased survival of HR-proficient cells in both 2D cultures and 3D spheroid assays with lower EC50 values than olaparib or vorinostat alone. Importantly, lung metastasis formation was significantly impaired by dual PARP-HDAC inhibition. Conclusion: Combination of PARP inhibition and HDAC inhibition showed increased efficacy compared to single agent PARP inhibition in HR-proficient cells. Development of bifunctional inhibitors may provide a novel therapeutic opportunity for tumors with limited response rates to single agent PARPi. Citation Format: Sarah Truong, Louise Ramos, Beibei Zhai, Fariba Ghaidi, Mona Marzban, Hans Adomat, Xiaoqi Chen, John Langlands, Dennis Brown, Jeffrey Bacha, Colin Collins, Poul H. Sorensen, Wang Shen, Mads Daugaard. Pharmacological synthetic lethality by co-inhibition of PARP and HDAC enzymes [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB273.

Controlling Relative miRNA level as Target Therapy of the BRCA Mutation and Its Challenges

In the past few decades, the diagnosis, prevention, and treatment of BRCA1/2-related cancer, especially breast cancer and ovarian cancer, have been a topic of great concern to scientists and the public. People with mutated BRCA genes are more likely to develop breast and ovarian cancer, and such causes of these types of cancer are inherited. Till now, there is no perfect solution for this gene defect. microRNAs (miRNAs), as important gene expression regulation molecules in humans, are considered to have the potential to be a tool for early diagnosis of such gene defects. In this review, the literature on miRNA closely related to BRCA gene regulation is reviewed, and the mechanism of miRNA causing BRCA gene variation is discussed. The online databases used in this research are PubMed, Nature Journals, ScienceDirect, The European Bioinformatics Institute (EBI), and Google Scholar. The search terms are “BRCA gene mutation”, “BRCA gene function”, “PARP inhibitor”, “miRNA for BRCA regulation”, “Target therapy for BRCA gene mutation”, “Drug resistance”, and “Target specificity”. This paper aims to discuss the possibility of reducing the incidence of BRCA gene mutation by controlling the content of relative miRNAs – reducing miRNAs that inhibit BRCA gene expression and increasing miRNAs that promote BRCA gene expression– and how to restore the function of the mutated BRCA gene by this means. The population that develops breast and ovarian cancer has been on the rise for decades, and the age of patients is getting younger. If miRNA can be developed as an early diagnostic tool, it will enhance the power of current cancer screening techniques and provide a more stable basis for early prevention and subsequent treatment.

Abstract 6256: Prevalence of BRCA1 and BRCA2 proteins in breast cancer in a nigerian population and their relationship with different breast cancer morphological variants

Abstract Background: Breast cancer is the commonest site specific cancer in women and a leading cause of cancer death among women in Nigeria and globally. The trend in Nigeria and Africa is that breast cancers are seen in younger age groups, are of higher grades and follow an aggressive course. It has been suggested that this may largely be due to mutation in BRCA genes with the attendant alteration in function of its proteins. This study aimed at determining the prevalence of BRCA1 and BRCA2 proteins in breast cancers seen in our environment as well as to see any association between these proteins and different morphological variants. Materials and Methods: A descriptive study using tissue blocks of all histologically diagnosed breast cancer in our department between 2013 and 2017. Fresh sections were recut for histological grading and immunohistochemistry. Proteintech BRCA1 and BRCA2 polyclonal antibodies and detection kit were used. Results: One hundred and thirty (130) cases met the inclusion criteria for this study. The mean (SD) age of the patients was 44.8 (10.3) years with ages ranging from 26 to 79 years. There were more cases of breast cancer (73.1%) seen before 50 years. Two (2) Male Breast Cancer (MBC) cases were seen, giving the female to male ratio of 64:1. The commonest morphological variant encountered was Invasive Carcinoma, No Special Type at 84.6% of cases. This was followed by invasive medullary (7.8%). The least common variant was papillary cancer at 0.8%. The tumors seen were mostly grade 3 (71.2%), followed by grade 2 at 22.7% and the least was grade 1 at 6.1%. Positivity for BRCA1 and BRCA2 proteins was seen in 27.7% and 30.0% of cases respectively. One of the MBC showed reactivity for BRCA1 protein. No significant relationship was seen between BRCA 1/2 proteins expression and age or breast cancer histotypes. Conclusion: BRCA 1 and 2 proteins are an important risk factor for breast cancers seen in this environment. However, there is no association with age distribution and morphological variants of the breast cancer in our population. Citation Format: Solomon Raphael, Abdul Oluwasesan. Prevalence of BRCA1 and BRCA2 proteins in breast cancer in a nigerian population and their relationship with different breast cancer morphological variants [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6256.

Abstract 2425: Pairwise analysis of plasma cell-free DNA before and after paclitaxel plus ramucirumab treatment in patients with metastatic gastric cancer

Abstract Background: Plasma cell-free DNA (cfDNA) analysis has emerged as an appealing alternative to detect somatic mutations. This study compared cfDNA at baseline (baseline-cfDNA) and progressive disease (PD-cfDNA) and tumor tissue DNA (ttDNA) in patients with metastatic gastric cancer who underwent palliative second-line paclitaxel+ramucirumab treatment. Methods: We conducted targeted sequencing of 106 cancer-related genes using germline DNA, baseline-cfDNA, and PD-cfDNA samples. The results were then compared with conventional cancer panel results using ttDNA. Results: Of 76 consecutively enrolled patients who received paclitaxel+ramucirumab treatment, 46 patients (27 males; median age 57.5 [range, 32-73] years) with access to all three samples were analyzed along with their ttDNA data. A total of 138, 145, and 80 mutations were detected in baseline-cfDNA, PD-cfDNA, and ttDNA respectively. Combined analysis of baseline-cfDNA and ttDNA revealed that TP53 (56.5%) was the most frequently mutated gene, followed by CDH1 (26.1%), KRAS (21.7%), and APC (13.5%). For the top four genes, the sensitivity and positive predictive value of baseline-cfDNA compared with ttDNA were 71.8% and 51.9%, respectively. Compared with ttDNA alone, 32 patients (70.0%) benefited from baseline-cfDNA in detecting novel mutations. When combined with baseline-cfDNA and PD-cfDNA, novel mutations were discovered in 34 patients (73.9%). Of note, PD-cfDNA analysis detected 9 novel pathogenic mutations in TP53, APC, PIK3CA, CDH1, RNF43, CTNNB1, and BRCA2 genes in 8 patients (17.4%) after treatment. In baseline-cfDNA, patients with a circulating ttDNA fraction concentration at 110-160 bp of &amp;gt;4.3777 ng/µL had significantly shorter progression-free survival (PFS) (median 3.5 vs. 5.3 months, P=0.016). In addition, maximal variant allele frequency (VAF) values of &amp;gt;0.1045 (median 3.4 vs. 5.2 months, P=0.022) and the sum of VAF values of &amp;gt;0.2071 (median 3.4 vs. 5.2 months, P=0.028) were significantly associated with shorter PFS. In patients with TP53 mutations, those with TP53 VAF values of &amp;gt;0.1014 significantly had worse PFS (median 4.6 vs. 6.4 months, P=0.022). Conclusions: Although cfDNA could not entirely take over the role of ttDNA, cfDNA analysis identified additional somatic mutations that were otherwise missed by ttDNA alone. Moreover, PD-cfDNA analysis detected novel pathogenic mutations that developed during treatment, implicating the clonal evolution of cancer. In addition, baseline cfDNA predicted PFS of patients receiving paclitaxel+ramucirumab therapy. Citation Format: Ji-Won Kim, Dong Soo Kyung, Won Yeong Ko, Hwang-Phill Kim, Sung-Hyun Hwang, Kui-Jin Kim, Ju Hyun Lee, Jeongmin Seo, Minsu Kang, Eun Hee Jung, Koung Jin Suh, Se Hyun Kim, Jin Won Kim, Yu Jung Kim, Jee Hyun Kim, Keun-Wook Lee. Pairwise analysis of plasma cell-free DNA before and after paclitaxel plus ramucirumab treatment in patients with metastatic gastric cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2425.

BRCA1 deficiency enhances the aggressiveness of breast cancer cells expressing HPV16 oncoproteins.

The precise etiology of breast cancer is not completely understood, although women with BRCA1 gene mutations have a significantly increased risk of developing the disease. In addition, sporadic breast cancer is frequently associated with decreased BRCA1 gene expression. Growing evidence of Human papillomaviruses (HPVs) infections in breast tumors has raised the possibility of the involvement of HPVs in the pathogenesis of breast cancer. We investigated whether the effects of HPV oncoproteins E6 and E7 were influenced by the expression levels of BRCA1. HPV16E6E7 (prototype or E6D25E/E7N29S Asian variant type) were stably expressed in MDA-MB231 breast cancer cells, wild type for BRCA1, or with BRCA1 knocked down. Expression of HPV16E6E7 oncogenes did not affect BRCA1 levels and the abundance of HPV16E6E7 was not altered by BRCA1 knockdown. BRCA1 levels did not alter HPV16E6E7-dependent degradation of G1-S cell cycle proteins p53 and pRb. However, we found that the expression of G2-M cell cycle protein cyclin B1 enhanced by HPV16E6E7 was impacted by BRCA1 levels. Especially, we found the correlation between BRCA1 and cyclin B1 expression and this was also confirmed in breast cancer samples from a Thai cohort. We further demonstrated that the combination of HPV oncoproteins and low levels of BRCA1 protein appears to enhance proliferation and invasion. Transactivation activities of HPV16E6E7 on genes regulating cell proliferation and invasion (TGF-β and vimentin) were significantly increased in BRCA1-deficient cells. Our results indicate that a deficiency of BRCA1 promotes the transactivation activity of HPV16E6E7 leading to increase of cell proliferation and invasion. HPV infection appears to have the potential to enhance the aggressiveness of breast cancers, especially those deficient in BRCA1.