Orla McNally

Whole–genome characterization of chemoresistant ovarian cancer

Patients with high-grade serous ovarian cancer (HGSC) have experienced little improvement in overall survival, and standard treatment has not advanced beyond platinum-based combination chemotherapy, during the past 30 years. To understand the drivers of clinical phenotypes better, here we use whole-genome sequencing of tumour and germline DNA samples from 92 patients with primary refractory, resistant, sensitive and matched acquired resistant disease. We show that gene breakage commonly inactivates the tumour suppressors RB1, NF1, RAD51B and PTEN in HGSC, and contributes to acquired chemotherapy resistance. CCNE1 amplification was common in primary resistant and refractory disease. We observed several molecular events associated with acquired resistance, including multiple independent reversions of germline BRCA1 or BRCA2 mutations in individual patients, loss of BRCA1 promoter methylation, an alteration in molecular subtype, and recurrent promoter fusion associated with overexpression of the drug efflux pump MDR1.

Molecular correlates of platinum response in human high-grade serous ovarian cancer patient-derived xenografts

Improvement in the ability to target underlying drivers and vulnerabilities of high‐grade serous ovarian cancer (HG‐SOC) requires the development of molecularly annotated pre‐clinical models reflective of clinical responses.

LRP1B Deletion in High-Grade Serous Ovarian Cancers Is Associated with Acquired Chemotherapy Resistance to Liposomal Doxorubicin

High-grade serous cancer (HGSC), the most common subtype of ovarian cancer, often becomes resistant to chemotherapy, leading to poor patient outcomes. Intratumoral heterogeneity occurs in nearly all solid cancers, including ovarian cancer, contributing to the development of resistance mechanisms. In this study, we examined the spatial and temporal genomic variation in HGSC using high-resolution single-nucleotide polymorphism arrays. Multiple metastatic lesions from individual patients were analyzed along with 22 paired pretreatment and posttreatment samples. We documented regions of differential DNA copy number between multiple tumor biopsies that correlated with altered expression of genes involved in cell polarity and adhesion. In the paired primary and relapse cohort, we observed a greater degree of genomic change in tumors from patients that were initially sensitive to chemotherapy and had longer progression-free interval compared with tumors from patients that were resistant to primary chemotherapy. Notably, deletion or downregulation of the lipid transporter LRP1B emerged as a significant correlate of acquired resistance in our analysis. Functional studies showed that reducing LRP1B expression was sufficient to reduce the sensitivity of HGSC cell lines to liposomal doxorubicin, but not to doxorubicin, whereas LRP1B overexpression was sufficient to increase sensitivity to liposomal doxorubicin. Together, our findings underscore the large degree of variation in DNA copy number in spatially and temporally separated tumors in HGSC patients, and they define LRP1B as a potential contributor to the emergence of chemotherapy resistance in these patients.

Paclitaxel and Its Evolving Role in the Management of Ovarian Cancer

Paclitaxel, a class of taxane with microtubule stabilising ability, has remained with platinum based therapy, the standard care for primary ovarian cancer management. A deeper understanding of the immunological basis and other potential mechanisms of action together with new dosing schedules and/or routes of administration may potentiate its clinical benefit. Newer forms of taxanes, with better safety profiles and higher intratumoural cytotoxicity, have yet to demonstrate clinical superiority over the parent compound.

Intravenous leiomyomatosis with intracardiac extension – A review of diagnosis and management with an illustrative case

Intravenous leiomyomatosis with intracardiac extension is an uncommon pathologic progression of uterine leiomyomata. It is a histologically benign condition, however due to interfence with right sided cardiac function patients may present with marked cardiovascular compromise and present a diagnostic dilemma to clinicians who are unfamiliar with this condition. Given the rarity of this condition, experience in individual institutions is usually limited to a few cases. We present an illustrative case and provide a review of the clinical presentation, preoperative assessment, operative approach, pathology and postoperative issues. The importance of a multidisciplinary approach to diagnosis and management is highlighted. Operative management aims to completely resect all tumour in the safest manner for the patient, most commonly via single or two stage operation. Where complete resection is achieved, recurrence appears to be a rare event.

Targeted Disruption of the JAK2/STAT3 Pathway in Combination with Systemic Administration of Paclitaxel Inhibits the Priming of Ovarian Cancer Stem Cells Leading to a Reduced Tumor Burden

Chemotherapy resistance associated with recurrent disease is the major cause of poor survival of ovarian cancer patients. We have recently demonstrated activation of the JAK2/STAT3 pathway and the enhancement of a cancer stem cell (CSC)-like phenotype in ovarian cancer cells treated in vitro with chemotherapeutic agents. To elucidate further these mechanisms in vivo, we used a two-tiered paclitaxel treatment approach in nude mice inoculated with ovarian cancer cells. In the first approach, we demonstrate that a single intraperitoneal administration of paclitaxel in mice 7 days after subcutaneous transplantation of the HEY ovarian cancer cell line resulted in a significant increase in the expression of CA125, Oct4, and CD117 in mice xenografts compared to control mice xenografts which did not receive paclitaxel. In the second approach, mice were administered once weekly with paclitaxel and/or a daily dose of the JAK2-specific inhibitor, CYT387, over 4 weeks. Mice receiving paclitaxel only demonstrated a significant decrease in tumor volume compared to control mice. At the molecular level, mouse tumors remaining after paclitaxel administration showed a significant increase in the expression of Oct4 and CD117 coinciding with a significant activation of the JAK2/STAT3 pathway compared to control tumors. The addition of CYT387 with paclitaxel resulted in the suppression of JAK2/STAT3 activation and abrogation of Oct4 and CD117 expression in mouse xenografts. This coincided with significantly smaller tumors in mice administered CYT387 in addition to paclitaxel, compared to the control group and the group of mice receiving paclitaxel only. These data suggest that the systemic administration of paclitaxel enhances Oct4- and CD117-associated CSC-like marker expression in surviving cancer cells in vivo, which can be suppressed by the addition of the JAK2-specific inhibitor CYT387, leading to a significantly smaller tumor burden. These novel findings have the potential for the development of CSC-targeted therapy to improve the treatment outcomes of ovarian cancer patients.

Mainstreaming cancer genetics: A model integrating germline BRCA testing into routine ovarian cancer clinics

OBJECTIVE Owing to the rapid increase in clinical need, we aimed to implement and review the performance of a mainstreaming model of germline BRCA1/2 genetic testing in eligible women with high grade non-mucinous epithelial ovarian cancer via a Genetic Counselor embedded in the gynecology oncology clinic. METHODS The model implemented involved a specialized referral form, weekly genetics-lead multidisciplinary review of referrals, and pre- and post-test genetic counseling provided by an embedded genetic counselor during chemotherapy chair time. Performance and outcomes were retrospectively audited over the following two consecutive one year periods, including survey data on medical specialist comfort with mainstreaming and the model. RESULTS Sixty-four women underwent mainstreamed BRCA1/2 testing over the two year post-implementation period with a rate of detection of BRCA1/2 pathogenic variants of 17%. The referral rate for eligible women significantly increased to over 90% (p<0.001). The median time from referral to delivery of genetic testing results was less than five months, with >90% of patients receiving results during first line chemotherapy. Genetic counseling time decreased from 120 to 54min. Cancer specialists were comfortable with the model. CONCLUSIONS The mainstreaming model proved effective, increasing uptake of genetic testing in eligible patients to over 90%; it was efficient for patients, genetic counselors and cancer specialists and acceptable to cancer specialists. It facilitated co-location of genetic and oncology service delivery but separation of clinical responsibility for genetic testing to a specialist genetics service, ensuring accurate and robust patient-centred care.

A community-based model of rapid autopsy in end-stage cancer patients

To the Editor: Systematic genomic studies, including the Cancer Genome Atlas (TCGA)1 and the International Cancer Genome Consortium (ICGC)2, have provided an unprecedented catalog of driver mutations in human cancer. However, these studies use mainly primary, pre-treatment tumor material obtained at surgery with curative intent. There is an urgent need to identify and characterize resistance mechanisms to understand how cancers can evade even the best medical efforts and kill patients; therefore, access to end-stage disease is important. Solid cancers show considerable spatial3, temporal4,5 and genomic heterogeneity at diagnosis. Selective pressure and mutagenic impact of treatment6 drives intra-patient evolution of cancer cell populations4,7. Understanding acquired resistance requires access to paired preand post-treatment samples4,7; however, curative surgery is typically confined to patients with locoregional disease, and opportunities for tumor sampling in advanced disseminated disease are limited. Here, we describe Cancer Tissue Collection After Death (CASCADE), an autopsy program that overcomes logistical challenges to enable collection of samples at end stage for research in melanoma and breast, ovarian and prostate cancers. For the CASCADE study, we aimed to recruit cancer patients close to the end of life, including those outside the minority of patients who die in hospitals. To preserve tissue integrity, autopsies must commence within a few hours of death, requiring access to around-the-clock services. Intervention in the emotionally charged end-of-life environment must be managed in an ethical manner and to a high standard. Finally, we aimed for the study to be highly cost-effective. We believe our approach to meeting these challenges is applicable to researchers in other large urban centers. Here we summarize the main steps in CASCADE’s operating protocol and our experiences from the initial 3 years and 30 autopsies performed (Fig. 1). Information about institutional review board approvals (including a detailed patient informationand-consent form), the autopsy procedure and certain laboratory processes is given in Supplementary Methods and Supplementary Figure 1. Recruitment of participants was led by the clinicians. Such discussions require careful consideration, in timing and in language, and were initiated only if there was a perception that tissue donation would be acceptable to the patients and their families. Factors suggesting acceptability include the emotional stability of the participant and family members and their clarity about and acceptance of the terminal nature of the disease. On occasion, participants prompted discussion by asking about organ or body donation. Consent discussions typically involved oncologists and/or palliative care physicians employed at recruiting hospitals who had established a care relationship with the participant and their family during the patient’s cancer journey. Frequently, the study was introduced at one meeting and discussed over several subsequent clinic visits, allowing patients and their families time to consider participation. We view the involvement of family members in the consent process as essential to support the participant and facilitate decisionmaking. Involvement of family members also ensures that they are fully aware of the autopsy process and helps to clarify funeral arrangements for the study team. After obtaining consent, study investigators collated clinical information, including that related to past and current treatment and diagnostic procedures such as imaging, on an ongoing basis. Between September 2012 and August 2015, 40 patients were approached, and 37 (92.5%) expressed interest in participating. Of those 32 patients (80%) consented; the other 5 had rapid clinical deterioration precluding

Predictive value of magnetic resonance imaging in assessing myometrial invasion in endometrial cancer: is radiological staging sufficient for planning conservative treatment?

Objectives: There has been an increasing interest in accurately assessing tumors preoperatively to plan appropriate surgery or, in some low-risk patients, conservative treatment. We wish to determine the accuracy of magnetic resonance imaging (MRI) in predicting myometrial invasion in endometrial cancer and whether it is a safe and suitable tool for planning conservative treatment. Materials and Methods: We compared MRI scans and final histopathologic diagnoses of 111 patients with endometrioid adenocarcinoma over a 6-year period at a major tertiary centre. Data were analyzed collectively and according to histological differentiation and types of MRI scans (1.5 vs 3 T). Outcomes were presence versus absence of myometrial invasion and recently revised International Federation of Gynecology and Obstetrics stage IA (up to 50% myometrial invasion) versus deep invasion. Results: Magnetic resonance imaging had a high negative predictive value for the presence of deep invasion (87% overall and 95% for grade 1 disease). However, although the positive predictive value for the presence of any myometrial invasion was high, negative predictive values were poor (35% for all grades and 46% for grade 1). There was no difference between 1.5- and 3-T scanning. Conclusions: Magnetic resonance imaging is a suitable screening tool for the presence of stage IA disease under the newly revised International Federation of Gynecology and Obstetrics staging system. The significance of this finding will depend on whether clinicians are willing to treat all grade 1 stage IA disease (under the revised system) as low risk and to deem selected patients in this group suitable for more conservative treatment.

Homologous Recombination DNA Repair Pathway Disruption and Retinoblastoma Protein Loss Are Associated with Exceptional Survival in High-Grade Serous Ovarian Cancer.

Purpose: Women with epithelial ovarian cancer generally have a poor prognosis; however, a subset of patients has an unexpected dramatic and durable response to treatment. We sought to identify clinical, pathological, and molecular determinants of exceptional survival in women with high-grade serous cancer (HGSC), a disease associated with the majority of ovarian cancer deaths. Experimental Design: We evaluated the histories of 2,283 ovarian cancer patients and, after applying stringent clinical and pathological selection criteria, identified 96 with HGSC that represented significant outliers in terms of treatment response and overall survival. Patient samples were characterized immunohistochemically and by genome sequencing. Results: Different patterns of clinical response were seen: long progression-free survival (Long-PFS), multiple objective responses to chemotherapy (Multiple Responder), and/or greater than 10-year overall survival (Long-Term Survivors). Pathogenic germline and somatic mutations in genes involved in homologous recombination (HR) repair were enriched in all three groups relative to a population-based series. However, 29% of 10-year survivors lacked an identifiable HR pathway alteration, and tumors from these patients had increased Ki-67 staining. CD8+ tumor-infiltrating lymphocytes were more commonly present in Long-Term Survivors. RB1 loss was associated with long progression-free and overall survival. HR deficiency and RB1 loss were correlated, and co-occurrence was significantly associated with prolonged survival. Conclusions: There was diversity in the clinical trajectory of exceptional survivors associated with multiple molecular determinants of exceptional outcome in HGSC patients. Concurrent HR deficiency and RB1 loss were associated with favorable outcomes, suggesting that co-occurrence of specific mutations might mediate durable responses in such patients. Clin Cancer Res; 24(3); 569–80. ©2017 AACR. See related commentary by Peng and Mills, p. 508