BRCA mutations lead to XIAP overexpression and sensitise ovarian cancer to inhibitor of apoptosis (IAP) family inhibitors.

BACKGROUND: We tested the hypothesis that inhibitor of apoptosis family (IAP) proteins may be altered in BRCA1-mutated ovarian cancers and that could affect the sensitivity to IAP inhibitors. METHODS: The levels of IAP proteins were evaluated in human cancers and cell lines. Cell lines were used to determine the effects of IAP inhibitors. The in vivo effects of treatments were evaluated in PDX mouse models. RESULTS: Expression of X-linked inhibitor of apoptosis (XIAP) is increased in BRCA1-mutated cancers and high levels are associated with improved patient outcomes after platinum chemotherapy. XIAP overexpression is mediated by NF-kB activation and is associated with an optimisation of PARP. BRCA1-mutated cell lines are particularly sensitive to IAP inhibitors due to an inhibitory effect on PARP. Both a BRCA1-mutated cell line with acquired resistance to PARP inhibitors and one with restored BRCA1 remain sensitive to IAP inhibitors. Treatment with IAP inhibitors restores the efficacy of PARP inhibition in these cell lines. The IAP inhibitor LCL161 alone and in combination with a PARP inhibitor, exhibited antitumour effects in PDX mouse models of resistant BRCA2 and 1-mutated ovarian cancer, respectively. CONCLUSION: A clinical trial may be justified to further investigate the utility of IAP inhibitors.

Taxane monotherapy regimens for the treatment of recurrent epithelial ovarian cancer.

BACKGROUND: Ovarian cancer is the seventh most frequent cancer diagnosis worldwide, and the eighth leading cause of cancer mortality. Epithelial ovarian cancer is the most common kind, accounting for 90% of cases. First-line therapy for women with epithelial ovarian cancer consists of a combination of cytoreductive surgery and platinum and taxane-based chemotherapy. However, more than 50% of women with epithelial ovarian cancer will experience a relapse and require further chemotherapy and at some point develop resistance to platinum-based drugs. Currently, guidance on the use of most chemotherapy drugs, including taxanes, is unclear for women whose epithelial ovarian cancer has recurred. Paclitaxel, topotecan, pegylated liposomal doxorubicin hydrochloride, trabectedin and gemcitabine are all licensed for use in the UK at the discretion of clinicians, following discussion with the women as to potential adverse effects. Taxanes can be given in once-weekly regimens (at a lower dose) or three-weekly regimens (at a higher dose), which may have differences in the severity of side effects and effectiveness. As relapsed disease suggests incurable disease, it is all the more important to consider side effects and the impact of treatment schedules, as well as quality of life, and not only the life-prolonging effects of treatment. OBJECTIVES: To assess the efficacy and toxicity of different taxane monotherapy regimens for women with recurrent epithelial ovarian, tubal or primary peritoneal cancer. SEARCH METHODS: We searched CENTRAL, MEDLINE and Embase, up to 22 March 2022. Other related databases and trial registries were searched as well as grey literature and no additional studies were identified. A total of 1500 records were identified. SELECTION CRITERIA: We included randomised controlled trials of taxane monotherapy for adult women diagnosed with recurrent epithelial ovarian, tubal or primary peritoneal cancer, previously treated with platinum-based chemotherapy. We included trials comparing two or more taxane monotherapy regimens. Participants could be experiencing their first recurrence of disease or any line of recurrence. DATA COLLECTION AND ANALYSIS: Two review authors screened, independently assessed studies, and extracted data from the included studies. The clinical outcomes we examined were overall survival, response rate, progression-free survival, neurotoxicity, neutropenia, alopecia, and quality of life. We performed statistical analyses using fixed-effect and random-effects models following standard Cochrane methodology. We rated the certainty of evidence according to the GRADE approach. MAIN RESULTS: Our literature search yielded 1500 records of 1466 studies; no additional studies were identified by searching grey literature or handsearching. We uploaded the search results into Covidence. After the exclusion of 92 duplicates, we screened titles and abstracts of 1374 records. Of these, we identified 24 studies for full-text screening. We included four parallel-group randomised controlled trials (RCTs). All trials were multicentred and conducted in a hospital setting. The studies included 981 eligible participants with recurrent epithelial ovarian cancer, tubal or primary peritoneal cancer with a median age ranging between 56 to 62 years of age. All participants had a WHO (World Health Organization) performance status of between 0 to 2. The proportion of participants with serous histology ranged between 56% to 85%. Participants included women who had platinum-sensitive (71%) and platinum-resistant (29%) relapse. Some participants were taxane pre-treated (5.6%), whilst the majority were taxane-naive (94.4%). No studies were classified as having a high risk of bias for any of the domains in the Cochrane risk of bias tool. We found that there may be little or no difference in overall survival (OS) between weekly paclitaxel and three-weekly paclitaxel, but the evidence is very uncertain (risk ratio (RR) of 0.94, 95% confidence interval (CI) 0.66 to 1.33, two studies, 263 participants, very low-certainty evidence). Similarly, there may be little or no difference in response rate (RR of 1.07, 95% CI 0.78 to 1.48, two studies, 263 participants, very low-certainty evidence) and progression-free survival (PFS) (RR of 0.83, 95% CI 0.46 to 1.52, two studies, 263 participants, very low-certainty evidence) between weekly and three-weekly paclitaxel, but the evidence is very uncertain. We found differences in the chemotherapy-associated adverse events between the weekly and three-weekly paclitaxel regimens. The weekly paclitaxel regimen may result in a reduction in neutropenia (RR 0.51, 95% 0.27 to 0.95, two studies, 260 participants, low-certainty evidence) and alopecia (RR 0.58, 95% CI 0.46 to 0.73, one study, 205 participants, low-certainty evidence). There may be little or no difference in neurotoxicity, but the evidence was very low-certainty and we cannot exclude an effect (RR 0.53, 95% CI 0.19 to 1.45, two studies, 260 participants). When examining the effect of paclitaxel dosage in the three-weekly regimen, the 250 mg/m2 paclitaxel regimen probably causes more neurotoxicity compared to the 175 mg/m2 regimen (RR 0.41, 95% CI 0.21 to 0.80, one study, 330 participants, moderate-certainty evidence). Quality-of-life data were not extractable from any of the included studies. AUTHORS' CONCLUSIONS: Fewer people may experience neutropenia when given weekly rather than three-weekly paclitaxel (low-certainty evidence), although it may make little or no difference to the risk of developing neurotoxicity (very low-certainty evidence). This is based on the participants receiving lower doses of drug more often. However, our confidence in this result is low and the true effect may be substantially different from the estimate of the effect. Weekly paclitaxel probably reduces the risk of alopecia, although the rates in both arms were high (46% versus 79%) (low-certainty evidence). A change to weekly from three-weekly chemotherapy could be considered to reduce the likelihood of toxicity, as it may have little or no negative impact on response rate (very low-certainty evidence), PFS (very low-certainty evidence) or OS (very low-certainty evidence). Three-weekly paclitaxel, given at a dose of 175 mg/m2 compared to a higher dose,probably reduces the risk of neurotoxicity.We are moderately confident in this result; the true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different. A change to 175 mg/m2 paclitaxel (from a higher dose), if a three-weekly regimen is used, probably has little or no negative impact on PFS or OS (very low-certainty evidence).

Identification and clinical impact of potentially actionable somatic oncogenic mutations in solid tumor samples.

BACKGROUND: An increasing number of anti-cancer therapeutic agents target specific mutant proteins that are expressed by many different tumor types. Successful use of these therapies is dependent on the presence or absence of somatic mutations within the patient's tumor that can confer clinical efficacy or drug resistance. METHODS: The aim of our study was to determine the type, frequency, overlap and functional proteomic effects of potentially targetable recurrent somatic hotspot mutations in 47 cancer-related genes in multiple disease sites that could be potential therapeutic targets using currently available agents or agents in clinical development. RESULTS: Using MassArray technology, of the 1300 patient tumors analysed 571 (43.9%) had at least one somatic mutation. Mutations were identified in 30 different genes. KRAS (16.5%), PIK3CA (13.6%) and BRAF (3.8%) were the most frequently mutated genes. Prostate (10.8%) had the lowest number of somatic mutations identified, while no mutations were identified in sarcoma. Ocular melanoma (90.6%), endometrial (72.4%) and colorectal (66.4%) tumors had the highest number of mutations. We noted high concordance between mutations in different parts of the tumor (94%) and matched primary and metastatic samples (90%). KRAS and BRAF mutations were mutually exclusive. Mutation co-occurrence involved mainly PIK3CA and PTPN11, and PTPN11 and APC. Reverse Phase Protein Array (RPPA) analysis demonstrated that PI3K and MAPK signalling pathways were more altered in tumors with mutations compared to wild type tumors. CONCLUSIONS: Hotspot mutational profiling is a sensitive, high-throughput approach for identifying mutations of clinical relevance to molecular based therapeutics for treatment of cancer, and could potentially be of use in identifying novel opportunities for genotype-driven clinical trials.

Inoperable de novo metastatic colorectal cancer with primary tumour in situ: Evaluating discordant responses to upfront systemic therapy of the primary tumours and metastatic sites and complications arising from primary tumours (experiences from an Irish Cancer Centre).

Systemic therapy is the mainstay of treatment for de novo metastatic colorectal cancer (mCRC). Heterogeneity between primary tumours and metastases may lead to discordant responses to systemic therapy at these sites. The aim of the present study was to examine these discrepancies and to evaluate the rates of complications arising from the primary tumour and the strategies employed to manage these complications. Electronic medical records were screened for patients eligible for data analysis between January 1st, 2014 and December 31st, 2019. All patients diagnosed with de novo mCRC with primary tumour in situ at the time of initial systemic therapy were included in data analysis. Responses in primary tumour and metastatic sites (according to the Response Evaluation Criteria In Solid Tumours v1.1), discrepancies in these responses and rates of complications arising from primary tumours were assessed along with patient, pathological or molecular factors that may be associated with these discrepant responses or primary tumour complications. A total of 50 patients were identified (median age, 62 years). Right-colon, left-colon and rectal primary tumours comprised 34, 44 and 22% of CRC cases, respectively. All patients received 5-fluorouracil-based chemotherapy (either alone or in combination with oxaliplatin or irinotecan). Disease response (DR), stable disease (SD) and progressive disease (PD) were observed as the first response to systemic therapy in 24, 62 and 12% of primary tumours and in 36, 18 and 44% of metastatic sites, respectively. Only 36% of patients demonstrated concordant responses between the primary tumours and metastases, while the remaining 62% demonstrated discordant responses between the primary tumour and distant metastases (22% had DR with SD; 36% had DR or SD with PD; and 4% had PD with SD in the primary tumour and metastases, respectively). Restaging images were not available for 2% of the patients. Approximately 30% of patients developed complications from primary tumours, including bowel obstruction (6.12%), perforation (6%), rectal pain (6%) and rectal bleeding (10%). Approximately 10% of patients underwent palliative stoma creation. Additionally, 12% required palliative radiotherapy to the primary tumour (due to localized complications arising from the tumour). Discordant responses to systemic therapy between primary tumours and metastases occurred in 60% of patients with de novo mCRC (with primary tumour in situ at the time of first systemic therapy). The observations of the present study have potential implications for molecular tissue analysis to help guide systemic therapy. Tissue from metastatic sites may be preferable to confirm biomarker status in mCRC based on this study.

Prevalence of tumor BRCA1 and BRCA2 dysfunction in unselected patients with ovarian cancer.

Objective: The therapeutic benefits of poly(ADP-ribose) polymerase inhibitors highlight the need to evaluate BRCA1/2 defects in tubal/ovarian cancer (OC). We sought to determine the pattern and disease characteristics associated with tumor BRCA1/2 mutations and BRCA1 methylation in women with OC. Methods: We obtained 111 OC specimens from 2 university hospitals and assessed BRCA1/2 mutations and BRCA1 methylation in tumor DNA. The frequency and pattern of BRCA1/2 defects were examined. Associations between patient/disease characteristics and BRCA1/2 defects were ascertained (Fisher's exact test). Platinum-free interval (PFI), progression-free survival (PFS), and overall survival (OS) based on the underlying BRCA1/2 defect were determined (Kaplan-Meier analysis [log-rank test]). Results: We observed a BRCA1/2 dysfunction rate of 40% (28/70) in high-grade serous tubal/ovarian cancer (HGSC), including 14.3% BRCA1 methylation (n=10), 7.1% BRCA1 mutation (n=5), and 18.6% BRCA2 mutation (n=13). Defects in BRCA1/2 genes were associated with stage III/IV HGSC (BRCA1 methylation: P=0.005 [stage III/IV] and P=0.004 [HGSC]; BRCA1/2 mutation: P=0.03 [stage III/IV] and P<0.001 [HGSC]). Patients with BRCA1/2-mutated cancers showed improved OS (hazard ratio [HR], 0.65; 95% confidence interval [CI], 0.43-0.99; P=0.045) and a trend toward improved PFI (HR, 0.48; 95% CI, 0.22-1.06; P=0.07) and PFS (HR, 0.72; 95% CI, 0.51-1.03; P=0.07). No survival differences were observed between BRCA1-methylated and BRCA1/2 wild-type non-BRCA1-methylated cancers. Conclusion: We observed a high tumor BRCA1/2 dysfunction rate in HGSC with a unique predominance of BRCA2 over BRCA1 mutations. While BRCA1/2 mutations conferred survival benefits in OC, no such association was observed with BRCA1 methylation.

BRCA1 Promoter Methylation and Clinical Outcomes in Ovarian Cancer: An Individual Patient Data Meta-Analysis.

BACKGROUND: BRCA1 methylation has been associated with homologous recombination deficiency, a biomarker of platinum sensitivity. Studies evaluating BRCA1-methylated tubal and ovarian cancer (OC) do not consistently support improved survival following platinum chemotherapy. We examine the characteristics of BRCA1-methylated OC in a meta-analysis of individual participant data. METHODS: Data of 2636 participants across 15 studies were analyzed. BRCA1-methylated tumors were defined according to their original study. Associations between BRCA1 methylation and clinicopathological characteristics were evaluated. The effects of methylation on overall survival (OS) and progression-free survival (PFS) were examined using mixed-effects models. All statistical tests were 2-sided. RESULTS: 430 (16.3%) tumors were BRCA1-methylated. BRCA1 methylation was associated with younger age and advanced-stage, high-grade serous OC. There were no survival differences between BRCA1-methylated and non-BRCA1-methylated OC (median PFS = 20.0 vs 18.5 months, hazard ratio [HR] = 1.01, 95% CI = 0.87 to 1.16; P = .98; median OS = 46.6 vs 48.0 months, HR = 1.02, 95% CI = 0.87 to 1.18; P = .96). Where BRCA1/2 mutations were evaluated (n = 1248), BRCA1 methylation displayed no survival advantage over BRCA1/2-intact (BRCA1/2 wild-type non-BRCA1-methylated) OC. Studies used different methods to define BRCA1 methylation. Where BRCA1 methylation was determined using methylation-specific polymerase chain reaction and gel electrophoresis (n = 834), it was associated with improved survival (PFS: HR = 0.80, 95% CI = 0.66 to 0.97; P = .02; OS: HR = 0.80, 95% CI = 0.63 to 1.00; P = .05) on mixed-effects modeling. CONCLUSION: BRCA1-methylated OC displays similar clinicopathological features to BRCA1-mutated OC but is not associated with survival. Heterogeneity within BRCA1 methylation assays influences associations. Refining these assays may better identify cases with silenced BRCA1 function and improved patient outcomes.

Combined Targeted Resequencing of Cytosine DNA Methylation and Mutations of DNA Repair Genes with Potential Use for Poly(ADP-Ribose) Polymerase 1 Inhibitor Sensitivity Testing.

Current molecular tumor diagnostics encompass panel sequencing to detect mutations, copy number alterations, and rearrangements. However, tumor suppressor genes can also be inactivated by methylation within their promoter region. These epigenetic alterations are so far rarely assessed in the clinical setting. Therefore, we established the AllCap protocol facilitating the combined detection of mutations and DNA methylation at the coding and promoter regions of 342 DNA repair genes in one experiment. We demonstrate the use of the protocol by applying it to ovarian cancer cell lines with different responsiveness to poly(ADP-ribose) polymerase inhibition. BRCA1, ATM, ATR, and EP300 mutations and methylation of the BRCA1 promoter were detected as potential predictors for therapy response. The required amount of input DNA was optimized, and the application to formalin-fixed, paraffin-embedded tissue samples was verified to improve the clinical applicability. Thus, by adding DNA methylation values to panel resequencings, the AllCap assay will add another important level of information to clinical tests and will improve stratification of patients for systemic therapies.

Molecular targeted therapy in ovarian cancer: what is on the horizon?

Over the past two decades, empirical optimization of cytotoxic chemotherapy combinations and surgical debulking procedures have improved outcomes and survival in epithelial ovarian cancer. Yet, this disease remains the fifth leading cause of cancer-related deaths in the US, as cure rates seem to have reached a plateau at approximately 20% with conventional chemotherapy. Novel high-throughput genomic and proteomic analyses have improved the molecular understanding of ovarian carcinogenesis, thereby providing a vast array of new potential drug targets with complex signalling interactions. In order to yield the most significant impact on disease outcome, it is necessary to carefully select, and subsequently target, the driving molecular pathway(s) within a tumour or tumour subtype, which are most likely to correspond to high-frequency mutations and genomic aberrations. The identification of biomarkers predictive of response to targeted therapy is essential to avoid poor responses to potentially useful drugs in unselected trial populations. With some promising, albeit early, phase III data on the angiogenesis inhibitor bevacizumab, exciting new opportunities lie ahead with the ultimate goal of personalizing therapies to individual tumour profiles.