Relevance of the common-sense model for people living with a genetic predisposition for breast and ovarian cancer.

OBJECTIVES: BRCA1/2 pathogenic variants have been associated with an increased risk for breast, ovarian, pancreatic, prostate cancer as well as melanoma. The present research uses the Leventhal's common-sense model of self-regulation (CSM), a theoretical framework highlighting the role of mental representations on responses to a health-threat. We aim at understanding the personal meaning and representation of living with an hereditary breast and ovarian cancer predisposition. METHOD: Semi-structured interviews of 15 BRCA carriers were analysed using the interpretative phenomenological analysis. RESULTS: Mental representations develops in childhood and are influenced by childhood emotional responses to the familial experience of the BRCA predisposition. Pre-existing beliefs about BRCA, even erroneous, are deeply anchored and not called into question by medical informations given during the genetic counselling. This is particularly true when medical information is perceived as too complex, inconsistent or in contradiction with familial experience. These beliefs about the consequences of being carriers of the BRCA gene influence emotional and behavioural experiences leading to experience fear, anxiety, lack of hope for future or self-identity change. For participants with a traumatic familial experience of cancer, the lack of treatment for this genetic disease generates a perpetual overestimation of cancers' risk and the feeling of an unending danger associated with early death despite breast and ovarian prophylactic surgery. When strong negative representations of the BRCA predisposition are experienced, dysfunctional health behaviours, such as drugs consumption or overuse of medical consultations, could appear consecutively to emotional disorders.

Molecular mechanism of PARP inhibitor resistance.

Poly (ADP-ribose) polymerases (PARP) inhibitors (PARPi) are the first-approved anticancer drug designed to exploit synthetic lethality. PARPi selectively kill cancer cells with homologous recombination repair deficiency (HRD), as a result, PARPi are widely employed to treated BRCA1/2-mutant ovarian, breast, pancreatic and prostate cancers. Currently, four PARPi including Olaparib, Rucaparib, Niraparib, and Talazoparib have been developed and greatly improved clinical outcomes in cancer patients. However, accumulating evidences suggest that required or de novo resistance emerged. In this review, we discuss the molecular mechanisms leading to PARPi resistances and review the potential strategies to overcome PARPi resistance.

Genetic landscape of homologous recombination repair and practical outcomes of PARPi therapy in ovarian cancer management.

Background: Genetic studies of ovarian cancer (OC) have historically focused on BRCA1/2 mutations, lacking other studies of homologous recombination repair (HRR). Poly (ADP-ribose) polymerase inhibitors (PARPi) exploit synthetic lethality to significantly improve OC treatment outcomes, especially in BRCA1/2 deficiency patients. Objectives: Our study aims to construct a mutation map of HRR genes in OC and identify factors influencing the efficacy of PARPi. Design: A retrospective observational analysis of HRR gene variation data from 695 OC patients from March 2019 to February 2022 was performed. Methods: The HRR gene variation data of 695 OC patients who underwent next-generation sequencing (NGS) in the First Affiliated Hospital of Zhengzhou University were retrospectively collected. Clinical data on the use of PARPi in these patients were also gathered to identify factors that may interfere with the efficacy of PARPi. Results: Out of 127 pathogenic variants in the BRCA1/2 genes, 104 (81.9%) were BRCA1 mutations, and 23 (18.1%) were BRCA2 mutations. Among the 59 variants of uncertain significance (VUS), 20 (33.9%) were BRCA1, while 39 (66.1%) were BRCA2 mutations. In addition to BRCA1/2, HRR gene results showed that 9 (69%) of 13 were HRR pathway pathogenic variants; and 16 (1.7%) of 116 VUS were Food and Drug Administration (FDA)-approved mutated HRR genes. Notably, the treatment regimen significantly influenced the effectiveness of PARPi, especially when using first-line maintenance therapy, leading to enhanced progression-free survival (PFS) compared to alternative protocols. Conclusion: Focusing on HRR gene mutations and supporting clinical research about PARPi in OC patients is crucial for developing precision treatment strategies and enhancing prognosis.

Rare Germline Variants in DNA Repair Genes Detected in BRCA-Negative Finnish Patients with Early-Onset Breast Cancer.

BACKGROUND: Breast cancer is the most common malignancy, with a mean age of onset of approximately 60 years. Only a minority of breast cancer patients present with an early onset at or before 40 years of age. An exceptionally young age at diagnosis hints at a possible genetic etiology. Currently, known pathogenic genetic variants only partially explain the disease burden of younger patients. Thus, new knowledge is warranted regarding additional risk variants. In this study, we analyzed DNA repair genes to identify additional variants to shed light on the etiology of early-onset breast cancer. METHODS: Germline whole-exome sequencing was conducted in a cohort of 63 patients diagnosed with breast cancer at or before 40 years of age (median 33, mean 33.02, range 23-40 years) with no known pathogenic variants in BRCA genes. After filtering, all detected rare variants were sorted by pathogenicity prediction scores (CADD score and REVEL) to identify the most damaging genetic changes. The remaining variants were then validated by comparison to a validation cohort of 121 breast cancer patients with no preselected age at cancer diagnosis (mean 51.4 years, range 28-80 years). Analysis of novel exonic variants was based on protein structure modeling. RESULTS: Five novel, deleterious variants in the genes WRN, RNF8, TOP3A, ERCC2, and TREX2 were found in addition to a splice acceptor variant in RNF4 and two frameshift variants in EXO1 and POLE genes, respectively. There were also multiple previously reported putative risk variants in other DNA repair genes. CONCLUSIONS: Taken together, whole-exome sequencing yielded 72 deleterious variants, including 8 novel variants that may play a pivotal role in the development of early-onset breast cancer. Although more studies are warranted, we demonstrate that young breast cancer patients tend to carry multiple deleterious variants in one or more DNA repair genes.

BRCA1/2 mutations and outcomes among Middle Eastern patients with early-onset breast cancer in Oman.

BACKGROUND: High prevalence of early-onset breast cancer (EOBC) has been reported in Middle Eastern populations. For example, in Oman more than 50% of patients with breast cancer (BC) are under age 45 at diagnosis. Causes for this high incidence are unknown. Germline BRCA gene mutations have been associated with EOBC, however, prevalence of these mutations and how they relate to EOBC in Oman has not been assessed. PATIENTS AND METHODS: Clinical data were collected for patients with BC treated at Royal Hospital, Oman between 2010 and 2022. Germline BRCA1/2 gene mutations were identified using sequencing and MLPA. Correlation and Kaplan-Meier survival analyses were performed to test relationships among clinico-pathological features, gene mutations, and outcomes. RESULTS: Total of 1336 Middle Eastern patients with BC were included; 611 were aged <45 at diagnosis (45.7%). No significant correlation was found between BRCA1/2 mutation status and EOBC (P = .229), and the majority of EOBC cases had no family history of BC. EOBC tumors did, however, differ in clinicopathological features; EOBCs were significantly larger (P < .0001), of higher grade (P < .0001), and included more HER2-enriched, and triple negative subtypes (P = .018) compared with later onset cases. Accordingly, survival analyses revealed that EOBC had significantly worse disease-free survival (P = .002). BRCA gene variants showed a distinct range of mutations including, in BRCA2, 3 previously unreported mutations and 4 potential founder recurrent mutations. CONCLUSION: Our findings showed that germline BRCA1/2 mutations were not over-represented in EOBC cases in Oman, and therefore are unlikely to be responsible for high EOBC rates.

Low-dose abiraterone plus Olaparib as a late-line treatment for mCRPC patients without BRCA1/2 mutations: a multicenter retrospective pilot study.

Although overall survival data are still premature, the PROpel study found radiological progression-free survival (PFS) benefits of abiraterone and olaparib in patients with metastatic castration-resistant prostate cancer (mCRPC). However, for patients who have not been genetically tested or lack BRCA1/2 mutations (BRCAm), this combination therapy has been questioned as a first-line conventional treatment for mCRPC, mainly due to significant health economics and side effects. In our retrospective study, we found that treatment with low-dose abiraterone plus olaparib as a late-line treatment for mCRPC could lead to prostate-specific antigen (PSA) and symptom PFS in selective cases even without BRCAm. The median PSA-PFS was 8 months (IQR: 6.5-11.5), with a median follow-up duration of 39.0 months (IQR: 27.5-64.5). Gene tests were conducted in all patients, identifying non-BRCA mutations through ctDNA testing (24%), tumor tissue testing (12%), or both (64%). Adverse events occurred in 72% of patients, with 16% experiencing Grade ≥ 3 events. Common adverse events included anemia (64%), decreased appetite (48%), and fatigue (25%). Our findings support low-dose abiraterone plus olaparib as a potential option for mCRPC patients without BRCAm, offering manageable safety and efficacy profiles.

Immediate Psychological Implications of Risk-Reducing Mastectomies in Women With Increased Risk of Breast Cancer: A Comparative Study.

BACKGROUND: Risk-reducing mastectomy is recommended for high-risk patients but may have significant psychological consequences. This study aimed to determine the differences in anxiety, depressive symptomatology, body image and quality of life in women with an increased risk of breast cancer immediately before and after undergoing risk-reducing mastectomy. METHODS: Eighty-eight women with an increased risk of breast cancer due to BRCA1/2 mutations or a previous cancer diagnosis participated in this study. Instruments used were the Hospital Anxiety and Depression Scale, Body Image Scale and the European Organization for Research and Treatment of Cancer Quality-of-Life Questionnaire Core 30 and Breast 23, administered 15-30 days before and after surgery. RESULTS: Following surgery, there was an immediate and significant worsening in anxiety, depressive symptomatology and body image. There was a significant deterioration in global, physical, role, and social functioning, as well as in body image and sexual enjoyment scales. Additionally, there were increases in fatigue, nausea and vomiting, constipation, dyspnoea, insomnia, appetite loss, perceived financial difficulties, pain, systemic therapy side effects, and breast and arm symptoms. However, there was an improvement in future perspective. These changes occurred independently of whether participants had a cancer diagnosis or BRCA1/2 mutation. CONCLUSION: Risk-reducing mastectomies have immediate psychological consequences. While these procedures improve future health perspective, they increase anxiety and depressive symptomatology and decrease body image and quality of life, regardless of cancer diagnosis or BRCA1/2 mutation. These findings highlight the psychological consequences of such surgical procedures, emphasizing the need for comprehensive psychological interventions both before and after surgery.

Evaluation of an Italian Population-Based Programme for Risk Assessment and Genetic Counselling and Testing for BRCA1/2-Related Hereditary Breast and Ovarian Cancer after 10 Years of Operation: An Observational Study Protocol.

Hereditary breast/ovarian cancer (HBOC) syndrome is caused by the inheritance of monoallelic germline BRCA1/2 gene mutations. If BRCA1/2 mutation carriers are identified before the disease develops, effective actions against HBOC can be taken, including intensive screening, risk-reducing mastectomy and salpingo-oophorectomy, and risk-reducing medications. The Italian National Prevention Plan mandates the creation of regional BRCA genetic testing programmes. So far, however, only informal data have been reported on their implementation. We have designed a study aimed at evaluating the results of a population-based programme for risk assessment and genetic counselling and testing for BRCA1/2-related HBOC that is underway in the Emilia-Romagna region (northern Italy). The programme-which is entirely free-includes basic screening with an estimate of the likelihood of carrying a BRCA1/2 mutation using a familial risk assessment tool, a closer examination of women with suspected risk increase, an assessment of the need for further genetic counselling and, if needed, genetic testing and risk-reducing interventions. In this paper, the design of the programme and the protocol of the study are presented. The study has an observational, historical cohort design. Eligible are the women found to be at an increased risk of HBOC (profile 3 women). The main objectives are (i) to determine the precision of the programme in measuring the level of risk of HBOC for profile 3 women; (ii) to determine the characteristics of profile 3 women and their association with the risk management strategy chosen; (iii) to compare the age at onset, histologic type, tumour stage, molecular subtype, and prognosis of breast/ovarian cancers observed in the cohort of profile 3 women with the features of sporadic cancers observed in the general female population; (iv) to determine the level and the determinants of adherence to recommendations; and (v) to determine the appropriateness and timing of risk-reducing surgery and medications. Investigating the quality and results of the programme is necessary because the best practices in risk assessment and genetic counselling and testing for BRCA1/2-related cancer and the challenges they encounter should be identified and shared. The study has the potential to provide sound empirical evidence for the factors affecting the effectiveness of this type of service.

Complex Interplay between DNA Damage and Autophagy in Disease and Therapy.

Cancer, a multifactorial disease characterized by uncontrolled cellular proliferation, remains a global health challenge with significant morbidity and mortality. Genomic and molecular aberrations, coupled with environmental factors, contribute to its heterogeneity and complexity. Chemotherapeutic agents like doxorubicin (Dox) have shown efficacy against various cancers but are hindered by dose-dependent cytotoxicity, particularly on vital organs like the heart and brain. Autophagy, a cellular process involved in self-degradation and recycling, emerges as a promising therapeutic target in cancer therapy and neurodegenerative diseases. Dysregulation of autophagy contributes to cancer progression and drug resistance, while its modulation holds the potential to enhance treatment outcomes and mitigate adverse effects. Additionally, emerging evidence suggests a potential link between autophagy, DNA damage, and caretaker breast cancer genes BRCA1/2, highlighting the interplay between DNA repair mechanisms and cellular homeostasis. This review explores the intricate relationship between cancer, Dox-induced cytotoxicity, autophagy modulation, and the potential implications of autophagy in DNA damage repair pathways, particularly in the context of BRCA1/2 mutations.

Effects of Hormonal Replacement Therapy and Mindfulness-Based Stress Reduction on Climacteric Symptoms Following Risk-Reducing Salpingo-Oophorectomy.

Breast Cancer Associated Susceptibility Proteins Type 1/2 (BRCA1/2) promote cellular functioning by modulating NRF2-mediated antioxidant signaling. Redox failure in women with BRCA1/2 insufficiency increases the risk for breast/ovarian/uterine cancers. Risk-reducing salpingo-oophorectomy (RRSO) is a prophylactic surgery of the reproductive organs, which is frequently conducted by the age of 40 to lower the occurrence of cancer in women with BRCA1/2 mutations. However, abrupt estrogen decline following RRSO causes ovarian failure, which implicates various cellular physiological processes, resulting in the increased release of free radicals and subsequent severe onset of menopausal symptoms. Comfort measures (e.g., hormonal replacement therapy (HRT) and mindfulness-based stress reduction (MBSR)) may improve chronological menopause-related quality of life, but their specific effects are not clear in women with gene mutations. Aiming to fill the gap, this study used path analysis to examine the effects of HRT and MBSR on menopausal symptoms among RRSO patients (N = 199, mean age = 50.5 ± 6.7 years). HRT directly alleviated the levels of urogenital symptoms (ß = -0.195, p = 0.005), which mediated its indirect significant effects on the somatic-vegetative and psychological symptoms of menopause (ß = -0.046, -0.067; both p values = 0.004, respectively), especially in BRCA2 carriers and in women who were currently physically active, premenopausal at the time of RRSO, had a high BMI, and had no history of breast cancer. It increased the severity of urogenital symptoms in women with a history of cancer. MBSR, on the other hand, was associated with indirect increases in the intensity of the somatic-vegetative and psychological symptoms of menopause (ß = 0.108, 0.029; p = 0.003, 0.033, respectively). It exerted positive direct effects on different menopausal symptoms in multigroup analysis. The results suggest that young women undergoing recent RRSO may benefit from HRT at an individual level, while their need for extensive measures to optimize their psychological wellbeing is ongoing. The adverse effects of MBSR, which are captured in the present study, imply that MBSR may interfere with redox sensitivity associated with estradiol fluctuations in BRCA1/2 carriers. Investigations are needed to test this hypothesis and elaborate on the underlying mechanisms in these women.

Case Report of Complete Response to Olaparib in a Patient with Breast Cancer Brain Metastases.

Introduction: Breast cancer is the second most common cause of central nervous system (CNS) metastases. It has been shown that the median time from breast cancer diagnosis to CNS metastasis is 30.9 months and that the overall median survival after metastasis is extremely poor at 6.8 months. Although treatment options for ErbB2 Receptor Tyrosine Kinase 2 (ERBB2)-positive breast cancer brain metastasis (BCBM) have been reported, effective treatment options for ERBB2-negative BCBM, which has one of the worst prognoses, are limited. Olaparib is one of the standard treatments for germline BRCA1/2 mutated (gBRCA1/2mt), ERBB2-negative, metastatic, or recurrent breast cancer. However, there is minimal existing evidence to evaluate the efficacy of olaparib in BCBM. Case Presentation: In our report, we assessed the case of a Japanese woman in her early 30s, ERBB2-negative, gBRAC2mt-positive BCBM, who achieved a complete response and prolonged progression-free survival of 9 months after the initiation of treatment with olaparib. Conclusions: Thus, our case report demonstrated the significant efficacy of olaparib in BCBM treatment. Furthermore, we highlighted the need for more studies to investigate the efficacy of olaparib and explore the efficacy of poly ADP ribose polymerase inhibitors in BCBM.

Current diagnostic and treatment options for pancreatic cancer in 2024.

Pancreatic ductal adenocarcinoma is a cancer disease with a very poor prognosis, which poses the third-leading cause of cancer-related deaths and whose incidence and mortality have been predicted to increase significantly in the upcoming years. Almost 80% of patients are diagnosed with advanced unresectable disease and therefore rely on palliative anticancer treatment with limited efficacy. However, even in case of 10-20 % of patients who have successfully undergone radical surgical resection of the localized disease and subsequent adjuvant chemotherapy, the vast majority will relapse within 2-3 years of surgery. The reasons can be found in late diagnosis due to the prolonged clinically asymptomatic course of the disease, complicated anatomical localization, significant tumor heterogeneity, which makes it difficult to test new drugs and, last but not least, in the presence of dense tumor stroma, that complicates the access of cytostatics and targeted drugs into the tumor tissue. Here we present a summary of current treatment options of localized and advanced pancreatic cancer, including molecular diagnostics and targeted treatment of small patients subgroups.

Synergistic antitumor effect of liposomal-based formulations of olaparib and topotecan in primary epithelial ovarian cancer cells.

BACKGROUND: Olaparib is a PARP inhibitor inducing synthetic lethality in tumors with deficient homologous recombination (HRD) caused by BRCA1/2 mutations. The FDA has approved monotherapy for first-line platinum-sensitive, recurrent high-grade epithelial ovarian cancer. Combination therapy alongside DNA-damaging therapeutics is a promising solution to overcome the limited efficacy in patients with HRD. The present study was designed to develop topotecan- and olaparib-loaded liposomes (TLL and OLL) and assess the effectiveness of their combination in patient-derived ovarian cancer samples. METHODS: We used HEOC, four clear-cell tumors (EOC 1-4), malignant ascites, and an OCI-E1p endometrioid primary ovarian cancer cell line and performed NGS analysis of BRCA1/2 mutation status. Antiproliferative activity was determined with the MTT assay. The Chou-Talalay algorithm was used to investigate the in vitro pharmacodynamic interactions of TLLs and OLLs. RESULTS: The OLL showed significantly higher efficacy in all ovarian cancer types with wild-type BRCA1/2 than a conventional formulation, suggesting potential for increased in vivo efficacy. The TLL revealed substantially higher toxicity to EOC 1, EOC 3, ascites and lower toxicity to HEOC than the standard formulation, suggesting better therapeutic efficacy and safety profile. The combination of studied compounds showed a higher reduction in cell viability than drugs used individually, demonstrating a synergistic antitumor effect at most of the selected concentrations. CONCLUSIONS: The concentration-dependent response of different ovarian cancer cell types to combination therapy confirms the need for in vitro optimization to maximize drug cytotoxicity. The OLL and TLL combination is a promising formulation for further animal studies, especially for eliminating epithelial ovarian cancer with wild-type BRCA1/2.

Endogenous base damage as a driver of genomic instability in homologous recombination-deficient cancers.

Homologous recombination (HR) is a high-fidelity DNA double-strand break (DSB) repair pathway. Both familial and somatic loss of function mutation(s) in various HR genes predispose to a variety of cancer types, underscoring the importance of error-free repair of DSBs in human physiology. While environmental sources of DSBs have been known, more recent studies have begun to uncover the role of endogenous base damage in leading to these breaks. Base damage repair intermediates often consist of single-strand breaks, which if left unrepaired, can lead to DSBs as the replication fork encounters these lesions. This review summarizes various sources of endogenous base damage and how these lesions are repaired. We highlight how conversion of base repair intermediates, particularly those with 5'or 3' blocked ends, to DSBs can be a predominant source of genomic instability in HR-deficient cancers. We also discuss how endogenous base damage and ensuing DSBs can be exploited to enhance the efficacy of Poly (ADP-ribose) polymerase inhibitors (PARPi), that are widely used in the clinics for the regimen of HR-deficient cancers.

Assessing the acceptability and appropriateness of a psychoeducational graphic novel about inherited cancer risk designed for men.

Men with germline pathogenic variants in BRCA1 or BRCA2 genes are at an increased lifetime risk for developing breast cancer, prostate cancer, and pancreatic cancer. Men report that managing clinical care is challenging because they are under-informed about their cancer risks. As the demand for genetic testing has increased, so too has the need to relay accurate and relatable genetic health information. This research developed and assessed the acceptability and appropriateness of a psychoeducational graphic novel designed for men to improve their cancer risk knowledge, manage their cancer-related uncertainty, and increase their intent to disclose their BRCA1/2 risks to family members and healthcare providers. Through purposive and snowball sampling, men (n = 20) and certified genetic counselors (CGCs; n = 15) participated in semi-structured interviews assessing the acceptability and appropriateness of the graphic novel. Interviews were audio-recorded, transcribed, and thematically analyzed. Both reported that the graphic novel confirmed risk information provided helpful resources, included relatable storylines, and had a unique visual appeal. Some men remained unsure about how to perform recommended screenings and how to talk to family members, particularly children, about BRCA1/2 test results after assessing the graphic novel. CGCs also discussed the helpfulness of the graphic novel for their practice. Given that this psychoeducational graphic novel was appealing to men and CGCs, it shows promise as an acceptable approach that may assist men in managing their cancer risks and communicating their genetic risk information to family members and healthcare providers.

Fear of cancer recurrence in breast cancer survivors carrying a BRCA1 or 2 genetic mutation : a cross-sectional study.

BACKGROUND: Fear of cancer recurrence (FCR) affects virtually all patients who have been treated for cancer, to varying degrees. Breast cancer survivors who carry a BRCA1 or BRCA2 gene mutation are at high risk of cancer recurrence. No study has yet assessed FCR specifically in this population. OBJECTIVES: This cross-sectional study, conducted in women who were treated for breast cancer and carrying a BRCA1/2 mutation, aimed to: (1) assess the mean level of FCR and estimate the proportion of patients with clinical levels of FCR; (2) examine the relationships between FCR and selected psychological variables (e.g., avoidance, intolerance to uncertainty) and quality of life; (3) explore whether FCR levels vary as a function of the past preventive treatment received; and (4) to assess the associations between FCR and the presence of decisional conflict or regret regarding the various preventive options. METHOD: Participants were recruited through an e-mail sent to an oncogenetic network mailing list (Réseau ROSE). Participants were asked to complete a battery of questionnaires online assessing FCR and other psychological and quality of life variables. RESULTS: A total of 89 women completed the survey. Most participants had undergone a preventive mastectomy (62.9%) and a preventive salpingo-oophorectomy (75.3%) at the time of the study. The mean Fear of Cancer Recurrence Inventory-severity score was 16.8, which exceeds the clinical cut-off score of 13, and 70.8% of the participants showed a clinical level of FCR. FCR was significantly associated with higher levels of anxiety and depression, and higher avoidance and intolerance of uncertainty, but not with quality of life. No significant difference was observed on the total FCR score between women who had received preventive surgery (mastectomy and/or salpingo-oophorectomy) and those considering it, and those not considering it. The association was significant between higher FRC scores and greater decisional conflicts and regrets about choosing to undergo preventive surgery. CONCLUSION: These data suggest that FCR is a significant problem for breast cancer survivors carrying a BRCA1/2 genetic mutation, even after undergoing a prophylactic surgery. This highlights the importance of providing these women with specific psychological intervention focusing on FCR.

The PARP1 selective inhibitor saruparib (AZD5305) elicits potent and durable antitumor activity in patient-derived BRCA1/2-associated cancer models.

BACKGROUND: Poly (ADP-ribose) polymerase 1 and 2 (PARP1/2) inhibitors (PARPi) are targeted therapies approved for homologous recombination repair (HRR)-deficient breast, ovarian, pancreatic, and prostate cancers. Since inhibition of PARP1 is sufficient to cause synthetic lethality in tumors with homologous recombination deficiency (HRD), PARP1 selective inhibitors such as saruparib (AZD5305) are being developed. It is expected that selective PARP1 inhibition leads to a safer profile that facilitates its combination with other DNA damage repair inhibitors. Here, we aimed to characterize the antitumor activity of AZD5305 in patient-derived preclinical models compared to the first-generation PARP1/2 inhibitor olaparib and to identify mechanisms of resistance. METHODS: Thirteen previously characterized patient-derived tumor xenograft (PDX) models from breast, ovarian, and pancreatic cancer patients harboring germline pathogenic alterations in BRCA1, BRCA2, or PALB2 were used to evaluate the efficacy of AZD5305 alone or in combination with carboplatin or an ataxia telangiectasia and Rad3 related (ATR) inhibitor (ceralasertib) and compared it to the first-generation PARPi olaparib. We performed DNA and RNA sequencing as well as protein-based assays to identify mechanisms of acquired resistance to either PARPi. RESULTS: AZD5305 showed superior antitumor activity than the first-generation PARPi in terms of preclinical complete response rate (75% vs. 37%). The median preclinical progression-free survival was significantly longer in the AZD5305-treated group compared to the olaparib-treated group (> 386 days vs. 90 days). Mechanistically, AZD5305 induced more replication stress and genomic instability than the PARP1/2 inhibitor olaparib in PARPi-sensitive tumors. All tumors at progression with either PARPi (39/39) showed increase of HRR functionality by RAD51 foci formation. The most prevalent resistance mechanisms identified were the acquisition of reversion mutations in BRCA1/BRCA2 and the accumulation of hypomorphic BRCA1. AZD5305 did not sensitize PDXs with acquired resistance to olaparib but elicited profound and durable responses when combined with carboplatin or ceralasertib in 3/6 and 5/5 models, respectively. CONCLUSIONS: Collectively, these results show that the novel PARP1 selective inhibitor AZD5305 yields a potent antitumor response in PDX models with HRD and delays PARPi resistance alone or in combination with carboplatin or ceralasertib, which supports its use in the clinic as a new therapeutic option.

Alterations in the expression of homologous recombination repair (HRR) genes in breast cancer tissues considering germline BRCA1/2 mutation status.

INTRODUCTION: Homologous recombination (HR) is a crucial DNA-repair mechanism, and its disruption can lead to the accumulation of mutations that initiate and promote cancer formation. The key HR genes, BRCA1 and BRCA2, are particularly significant as their germline pathogenic variants are associated with a hereditary predisposition to breast and/or ovarian cancer. MATERIALS AND METHODS: The study was performed on 45 FFPE breast cancer tissues obtained from 24 and 21 patients, with and without the germline BRCA1/2 mutation, respectively. The expression of 11 genes: BRCA1, BRCA2, ATM, BARD1, FANCA, FANCB, FANCI, RAD50, RAD51D, BRIP1, and CHEK2 was assessed using Custom RT2 PCR Array (Qiagen), and results were analysed using R. RESULTS: Cancer tissues from patients with BRCA1 or BRCA2 germline mutations displayed no significant differences in the expression of the selected HR genes compared to BRCA1 or BRCA2 wild-type cancer tissues. In BRCA1mut cancer tissues, BRCA1 expression was significantly higher than in BRCA2mut and BRCA wild-type cancer tissues. CONCLUSIONS: In cancer tissues harbouring either BRCA1 or BRCA2 germline mutations, no significant differences in expression were observed at the mRNA level of any tested HR genes, except BRCA1. However, the significant differences observed in BRCA1 expression between germline BRCA1mut, germline BRCA2mut and BRCA1/2wt tissues may indicate a compensatory mechanism at the mRNA level to mitigate the loss of BRCA1 function in the cells.

Fertility and Pregnancy-Related Issues in Young BRCA Carriers With Breast Cancer.

Approximately 10% to 15% of breast cancer cases in young women are diagnosed in patients harbouring germline (g) pathogenic or likely pathogenic variants (PVs) in the BReast CAncer 1 (BRCA1) or BReast CAncer 2 (BRCA2) genes. Preclinical and clinical studies showed a potential negative effect of germline BRCA1/2 (gBRCA1/2) PVs on ovarian reserve and reproductive potential, even before starting anticancer therapies. The aim of this article is to summarize the current literature on the fertility potential of young gBRCA1/2 PVs carriers with breast cancer and the risk of gonadotoxicity associated with anticancer treatments. Moreover, we describe the available evidence on the efficacy of fertility preservation techniques in young gBRCA1/2 PVs carriers and the safety data on having a pregnancy after breast cancer treatment.

[18F]F-Poly(ADP-Ribose) Polymerase Inhibitor Radiotracers for Imaging PARP Expression and Their Potential Clinical Applications in Oncology.

Including poly(ADP-ribose) polymerase (PARP) inhibitors in managing patients with inoperable tumors has significantly improved outcomes. The PARP inhibitors hamper single-strand deoxyribonucleic acid (DNA) repair by trapping poly(ADP-ribose)polymerase (PARP) at sites of DNA damage, forming a non-functional "PARP enzyme-inhibitor complex" leading to cell cytotoxicity. The effect is more pronounced in the presence of PARP upregulation and homologous recombination (HR) deficiencies such as breast cancer-associated gene (BRCA1/2). Hence, identifying HR-deficiencies by genomic analysis-for instance, BRCA1/2 used in triple-negative breast cancer-should be a part of the selection process for PARP inhibitor therapy. Published data suggest BRCA1/2 germline mutations do not consistently predict favorable responses to PARP inhibitors, suggesting that other factors beyond tumor mutation status may be at play. A variety of factors, including tumor heterogeneity in PARP expression and intrinsic and/or acquired resistance to PARP inhibitors, may be contributing factors. This justifies the use of an additional tool for appropriate patient selection, which is noninvasive, and capable of assessing whole-body in vivo PARP expression and evaluating PARP inhibitor pharmacokinetics as complementary to the currently available BRCA1/2 analysis. In this review, we discuss [18F]Fluorine PARP inhibitor radiotracers and their potential in the imaging of PARP expression and PARP inhibitor pharmacokinetics. To provide context we also briefly discuss possible causes of PARP inhibitor resistance or ineffectiveness. The discussion focuses on TNBC, which is a tumor type where PARP inhibitors are used as part of the standard-of-care treatment strategy.