The PARTNER trial of neoadjuvant olaparib with chemotherapy in triple-negative breast cancer.

PARTNER is a prospective, phase II-III, randomized controlled clinical trial that recruited patients with triple-negative breast cancer1,2, who were germline BRCA1 and BRCA2 wild type3. Here we report the results of the trial. Patients (n = 559) were randomized on a 1:1 basis to receive neoadjuvant carboplatin-paclitaxel with or without 150 mg olaparib twice daily, on days 3 to 14, of each of four cycles (gap schedule olaparib, research arm) followed by three cycles of anthracycline-based chemotherapy before surgery. The primary end point was pathologic complete response (pCR)4, and secondary end points included event-free survival (EFS) and overall survival (OS)5. pCR was achieved in 51% of patients in the research arm and 52% in the control arm (P = 0.753). Estimated EFS at 36 months in the research and control arms was 80% and 79% (log-rank P > 0.9), respectively; OS was 90% and 87.2% (log-rank P = 0.8), respectively. In patients with pCR, estimated EFS at 36 months was 90%, and in those with non-pCR it was 70% (log-rank P < 0.001), and OS was 96% and 83% (log-rank P < 0.001), respectively. Neoadjuvant olaparib did not improve pCR rates, EFS or OS when added to carboplatin-paclitaxel and anthracycline-based chemotherapy in patients with triple-negative breast cancer who were germline BRCA1 and BRCA2 wild type. ClinicalTrials.gov ID: NCT03150576 .

Long-term outcomes of young, node-negative, chemotherapy-naïve, triple-negative breast cancer patients according to BRCA1 status.

BACKGROUND: Due to the abundant usage of chemotherapy in young triple-negative breast cancer (TNBC) patients, the unbiased prognostic value of BRCA1-related biomarkers in this population remains unclear. In addition, whether BRCA1-related biomarkers modify the well-established prognostic value of stromal tumor-infiltrating lymphocytes (sTILs) is unknown. This study aimed to compare the outcomes of young, node-negative, chemotherapy-naïve TNBC patients according to BRCA1 status, taking sTILs into account. METHODS: We included 485 Dutch women diagnosed with node-negative TNBC under age 40 between 1989 and 2000. During this period, these women were considered low-risk and did not receive chemotherapy. BRCA1 status, including pathogenic germline BRCA1 mutation (gBRCA1m), somatic BRCA1 mutation (sBRCA1m), and tumor BRCA1 promoter methylation (BRCA1-PM), was assessed using DNA from formalin-fixed paraffin-embedded tissue. sTILs were assessed according to the international guideline. Patients' outcomes were compared using Cox regression and competing risk models. RESULTS: Among the 399 patients with BRCA1 status, 26.3% had a gBRCA1m, 5.3% had a sBRCA1m, 36.6% had tumor BRCA1-PM, and 31.8% had BRCA1-non-altered tumors. Compared to BRCA1-non-alteration, gBRCA1m was associated with worse overall survival (OS) from the fourth year after diagnosis (adjusted HR, 2.11; 95% CI, 1.18-3.75), and this association attenuated after adjustment for second primary tumors. Every 10% sTIL increment was associated with 16% higher OS (adjusted HR, 0.84; 95% CI, 0.78-0.90) in gBRCA1m, sBRCA1m, or BRCA1-non-altered patients and 31% higher OS in tumor BRCA1-PM patients. Among the 66 patients with tumor BRCA1-PM and ≥ 50% sTILs, we observed excellent 15-year OS (97.0%; 95% CI, 92.9-100%). Conversely, among the 61 patients with gBRCA1m and < 50% sTILs, we observed poor 15-year OS (50.8%; 95% CI, 39.7-65.0%). Furthermore, gBRCA1m was associated with higher (adjusted subdistribution HR, 4.04; 95% CI, 2.29-7.13) and tumor BRCA1-PM with lower (adjusted subdistribution HR, 0.42; 95% CI, 0.19-0.95) incidence of second primary tumors, compared to BRCA1-non-alteration. CONCLUSIONS: Although both gBRCA1m and tumor BRCA1-PM alter BRCA1 gene transcription, they are associated with different outcomes in young, node-negative, chemotherapy-naïve TNBC patients. By combining sTILs and BRCA1 status for risk classification, we were able to identify potential subgroups in this population to intensify and optimize adjuvant treatment.

AGO-OVAR 28/ENGOT-ov57. Niraparib alone versus niraparib in combination with bevacizumab in patients with carboplatin-taxane-based chemotherapy in advanced ovarian cancer: a multicenter randomized phase III trial.

BACKGROUND: Phase III trial data have shown a significant benefit by the addition of a maintenance treatment with niraparib, irrespective of BRCA or HRD status, in patients with advanced high-grade ovarian cancers; and, a significant benefit of the combination of olaparib and bevacizumab compared with bevacizumab monotherapy in HRD positive patients. However, it is unclear whether a PARP inhibitor monotherapy is sufficient, or if the addition of bevacizumab is needed. PRIMARY OBJECTIVES: This trial will investigate if the treatment strategy of carboplatin/paclitaxel/bevacizumab/niraparib is superior to the treatment of carboplatin/paclitaxel/niraparib in an all-comer population. STUDY HYPOTHESIS: Adding bevacizumab to chemotherapy followed by niraparib maintenance improves progression-free survival in patients with newly diagnosed advanced ovarian cancer. TRIAL DESIGN: AGO-OVAR 28/ENGOT-ov57 is an international, multicenter, randomized, prospective phase III trial within the the European Network for Gynecological Oncological Trial (ENGOT), led by the Arbeitsgemeinschaft Gynäkologische Onkologie (AGO) study group. All patients should have completed the first cycle of chemotherapy (carboplatin and paclitaxel) as part of the Study Run-In-Period. Prior to day 1 of cycle 2, patients with a valid central tumor BRCA (tBRCA) test result were randomized in a 1:1 ratio into either: Arm 1, to receive five additional cycles of carboplatin and paclitaxel q21d, followed by niraparib for up to 3 years; or Arm 2, to receive five additional cycles of carboplatin and paclitaxel plus bevacizumab q21d, followed by bevacizumab q21d (for up to 1 year), and niraparib for up to 3 years. MAJOR INCLUSION/EXCLUSION CRITERIA: The trial population is composed of adult patients with newly diagnosed, advanced high-grade epithelial ovarian cancer, primary peritoneal cancer, or fallopian tube cancer FIGO III/IV (except FIGO IIIA2 without nodal involvement). Patients who are scheduled for neoadjuvant chemotherapy and interval debulking surgery are also eligible for the trial. PRIMARY ENDPOINT: The primary endpoint is progression-free survival. SAMPLE SIZE: The study plans to recruit 970 patients (485 patients in each arm). ESTIMATED DATES FOR COMPLETING ACCRUAL AND PRESENTING RESULTS: The Last-Patient-In is expected to be enrolled in September 2024, with presentation of the primary endpoint in 2028. TRIAL REGISTRATION: NCT05009082; EudraCT Number: 2021-001271-16.

Effect of HIPEC according to HRD/BRCAwt genomic profile in stage III ovarian cancer: Results from the phase III OVHIPEC trial.

The addition of hyperthermic intraperitoneal chemotherapy (HIPEC) with cisplatin to interval cytoreductive surgery improves recurrence-free (RFS) and overall survival (OS) in patients with stage III ovarian cancer. Homologous recombination deficient (HRD) ovarian tumors are usually more platinum sensitive. Since hyperthermia impairs BRCA1/2 protein function, we hypothesized that HRD tumors respond best to treatment with HIPEC. We analyzed the effect of HIPEC in patients in the OVHIPEC trial, stratified by HRD status and BRCAm status. Clinical data and tissue samples were collected from patients included in the randomized, phase III OVHIPEC-1 trial. DNA copy number variation (CNV) profiles, HRD-related pathogenic mutations and BRCA1 promotor hypermethylation were determined. CNV-profiles were categorized as HRD or non-HRD, based on a previously validated algorithm-based BRCA1-like classifier. Hazard ratios (HR) and corresponding 99% confidence intervals (CI) for the effect of RFS and OS of HIPEC in the BRCAm, the HRD/BRCAwt and the non-HRD group were estimated using Cox proportional hazard models. Tumor DNA was available from 200/245 (82%) patients. Seventeen (9%) tumors carried a pathogenic mutation in BRCA1 and 14 (7%) in BRCA2. Ninety-one (46%) tumors classified as BRCA1-like. The effect of HIPEC on RFS and OS was absent in BRCAm tumors (HR 1.25; 99%CI 0.48-3.29), and most present in HRD/BRCAwt (HR 0.44; 99%CI 0.21-0.91), and non-HRD/BRCAwt tumors (HR 0.82; 99%CI 0.48-1.42), interaction P value: 0.024. Patients with HRD tumors without pathogenic BRCA1/2 mutation appear to benefit most from treatment with HIPEC, while benefit in patients with BRCA1/2 pathogenic mutations and patients without HRD seems less evident.

Adjuvant capecitabine-containing chemotherapy benefit and homologous recombination deficiency in early-stage triple-negative breast cancer patients.

BACKGROUND: The addition of adjuvant capecitabine to standard chemotherapy of early-stage triple-negative breast cancer (TNBC) patients has improved survival in a few randomised trials and in meta-analyses. However, many patients did not benefit. We evaluated the BRCA1-like DNA copy number signature, indicative of homologous recombination deficiency, as a predictive biomarker for capecitabine benefit in the TNBC subgroup of the FinXX trial. METHODS: Early-stage TNBC patients were randomised between adjuvant capecitabine-containing (TX + CEX: capecitabine-docetaxel, followed by cyclophosphamide-epirubicin-capecitabine) and conventional chemotherapy (T + CEF: docetaxel, followed by cyclophosphamide-epirubicin-fluorouracil). Tumour BRCA1-like status was determined on low-coverage, whole genome next-generation sequencing data using an established DNA comparative genomic hybridisation algorithm. RESULTS: For 129/202 (63.9%) patients the BRCA1-like status could be determined, mostly due to lack of tissue. During a median follow-up of 10.7 years, 35 recurrences and 32 deaths occurred. Addition of capecitabine appears to improve recurrence-free survival more among 61 (47.3%) patients with non-BRCA1-like tumours (HR 0.23, 95% CI 0.08-0.70) compared to 68 (52.7%) patients with BRCA1-like tumours (HR 0.66, 95% CI 0.24-1.81) (P-interaction = 0.17). CONCLUSION: Based on our data, patients with non-BRCA1-like TNBC appear to benefit from the addition of capecitabine to adjuvant chemotherapy. Patients with BRCA1-like TNBC may also benefit. Additional research is needed to define the subgroup within BRCA1-like TNBC patients who may not benefit from adjuvant capecitabine.

A Phase I dose-escalation study of two cycles carboplatin-olaparib followed by olaparib monotherapy in patients with advanced cancer.

Preclinical studies have shown synergistic effects when combining PARP1/2 inhibitors and platinum drugs in BRCA1/2 mutated cancer cell models. After a formulation change of olaparib from capsules to tablets, we initiated a dose finding study of olaparib tablets bidaily (BID) continuously with carboplatin to prepare comparative studies in this patient group. Patients were included in a 3 + 3 dose-escalation schedule: olaparib 25 mg BID and carboplatin area under the curve (AUC) 3 mg*min/mL d1/d22, olaparib 25 mg BID and carboplatin AUC 4 mg*min/mL d1/d22, followed by increasing dose-levels of olaparib from 50 mg BID, 75 mg BID, to 100 mg BID with carboplatin at AUC 4 mg*min/mL d1/d22. After two cycles, patients continued olaparib 300 mg BID as monotherapy. Primary objective was to assess the maximum tolerable dose (MTD). Twenty-four patients with a confirmed diagnosis of advanced cancer were included. Most common adverse events were nausea (46%), fatigue (33%) and platelet count decrease (33%). Dose-level 3 (olaparib 75 mg BID and carboplatin AUC 4 mg*min/mL; n = 6) was defined as MTD. Fourteen out of 24 patients (56%) had a partial response as best response (RECIST 1.1). Systemic exposure of the olaparib tablet formulation appeared comparable to the previous capsule formulation with olaparib tablet AUC0-12 of 16.3 µg/mL*h at MTD. Polymers of ADP-ribose levels in peripheral blood mononuclear cells were reduced by 98.7% ± 0.14% at Day 8 compared to Day 1 for dose-level 3. Olaparib tablets 75 mg BID and carboplatin AUC 4 mg*min/mL for two cycles preceding olaparib monotherapy 300 mg is a feasible and tolerable treatment schedule for patients with advanced cancer.

REV7 counteracts DNA double-strand break resection and affects PARP inhibition.

Error-free repair of DNA double-strand breaks (DSBs) is achieved by homologous recombination (HR), and BRCA1 is an important factor for this repair pathway. In the absence of BRCA1-mediated HR, the administration of PARP inhibitors induces synthetic lethality of tumour cells of patients with breast or ovarian cancers. Despite the benefit of this tailored therapy, drug resistance can occur by HR restoration. Genetic reversion of BRCA1-inactivating mutations can be the underlying mechanism of drug resistance, but this does not explain resistance in all cases. In particular, little is known about BRCA1-independent restoration of HR. Here we show that loss of REV7 (also known as MAD2L2) in mouse and human cell lines re-establishes CTIP-dependent end resection of DSBs in BRCA1-deficient cells, leading to HR restoration and PARP inhibitor resistance, which is reversed by ATM kinase inhibition. REV7 is recruited to DSBs in a manner dependent on the H2AX-MDC1-RNF8-RNF168-53BP1 chromatin pathway, and seems to block HR and promote end joining in addition to its regulatory role in DNA damage tolerance. Finally, we establish that REV7 blocks DSB resection to promote non-homologous end-joining during immunoglobulin class switch recombination. Our results reveal an unexpected crucial function of REV7 downstream of 53BP1 in coordinating pathological DSB repair pathway choices in BRCA1-deficient cells.

The BRCA1ness signature is associated significantly with response to PARP inhibitor treatment versus control in the I-SPY 2 randomized neoadjuvant setting.

BACKGROUND: Patients with BRCA1-like tumors correlate with improved response to DNA double-strand break-inducing therapy. A gene expression-based classifier was developed to distinguish between BRCA1-like and non-BRCA1-like tumors. We hypothesized that these tumors may also be more sensitive to PARP inhibitors than standard treatments. METHODS: A diagnostic gene expression signature (BRCA1ness) was developed using a centroid model with 128 triple-negative breast cancer samples from the EU FP7 RATHER project. This BRCA1ness signature was then tested in HER2-negative patients (n = 116) from the I-SPY 2 TRIAL who received an oral PARP inhibitor veliparib in combination with carboplatin (V-C), or standard chemotherapy alone. We assessed the association between BRCA1ness and pathologic complete response in the V-C and control arms alone using Fisher's exact test, and the relative performance between arms (biomarker × treatment interaction, likelihood ratio p < 0.05) using a logistic model and adjusting for hormone receptor status (HR). RESULTS: We developed a gene expression signature to identify BRCA1-like status. In the I-SPY 2 neoadjuvant setting the BRCA1ness signature associated significantly with response to V-C (p = 0.03), but not in the control arm (p = 0.45). We identified a significant interaction between BRCA1ness and V-C (p = 0.023) after correcting for HR. CONCLUSIONS: A genomic-based BRCA1-like signature was successfully translated to an expression-based signature (BRC1Aness). In the I-SPY 2 neoadjuvant setting, we determined that the BRCA1ness signature is capable of predicting benefit of V-C added to standard chemotherapy compared to standard chemotherapy alone. TRIAL REGISTRATION: I-SPY 2 TRIAL beginning December 31, 2009: Neoadjuvant and Personalized Adaptive Novel Agents to Treat Breast Cancer (I-SPY 2), NCT01042379 .

BRCA1-like profile predicts benefit of tandem high dose epirubicin-cyclophospamide-thiotepa in high risk breast cancer patients randomized in the WSG-AM01 trial.

BRCA1 is an important protein in the repair of DNA double strand breaks (DSBs), which are induced by alkylating chemotherapy. A BRCA1-like DNA copy number signature derived from tumors with a BRCA1 mutation is indicative for impaired BRCA1 function and associated with good outcome after high dose (HD) and tandem HD DSB inducing chemotherapy. We investigated whether BRCA1-like status was a predictive biomarker in the WSG AM 01 trial. WSG AM 01 randomized high-risk breast cancer patients to induction (2× epirubicin-cyclophosphamide) followed by tandem HD chemotherapy with epirubicin, cyclophosphamide and thiotepa versus dose dense chemotherapy (4× epirubicin-cyclophospamide followed by 3× cyclophosphamide-methotrexate-5-fluorouracil). We generated copy number profiles for 143 tumors and classified them as being BRCA1-like or non-BRCA1-like. Twenty-six out of 143 patients were BRCA1-like. BRCA1-like status was associated with high grade and triple negative tumors. With regard to event-free-survival, the primary endpoint of the trial, patients with a BRCA1-like tumor had a hazard rate of 0.2, 95% confidence interval (CI): 0.07-0.63, p = 0.006. In the interaction analysis, the combination of BRCA1-like status and HD chemotherapy had a hazard rate of 0.19, 95% CI: 0.067-0.54, p = 0.003. Similar results were observed for overall survival. These findings suggest that BRCA1-like status is a predictor for benefit of tandem HD chemotherapy with epirubicin-thiotepa-cyclophosphamide.

Copy number profiling by array comparative genomic hybridization identifies frequently occurring BRCA2-like male breast cancer.

Genomic aberrations can be used to subtype breast cancer. In this study, we investigated DNA copy number (CN) profiles of 69 cases of male breast cancer (MBC) by array comparative genomic hybridization (aCGH) to detect recurrent gains and losses in comparison with female breast cancers (FBC). Further, we classified these profiles as BRCA1-like, BRCA2-like or non-BRCA-like profiles using previous classifiers derived from FBC, and correlated these profiles with pathological characteristics. We observed large CN gains on chromosome arms 1q, 5p, 8q, 10p, 16p, 17q, and chromosomes 20 and X. Large losses were seen on chromosomes/chromosome arms 1p, 6p, 8p, 9, 11q, 13, 14q, 16q, 17p, and 22. The pattern of gains and losses in estrogen receptor positive (ER+) MBC was largely similar to ER+ FBC, except for gains on chromosome X in MBC, which were uncommon in FBC. Out of 69 MBC patients, 15 patients (22%) had a BRCA2-like profile, of which 2 (3%) were also BRCA1-like. One patient (1%) was only BRCA1-like; the remaining 53 (77%) patients were classified as non-BRCA-like. BRCA2-like cases were more often p53 accumulated than non-BRCA-like cases (P = 0.014). In conclusion, the pattern of gains and losses in ER+ MBC was largely similar to that of its ER+ FBC counterpart, except for gains on chromosome X in MBC, which are uncommon in FBC. A significant proportion of MBC has a BRCA2-like aCGH profile, pointing to a potentially hereditary nature, and indicating that they could benefit from a drug regimen targeting BRCA defects as in FBC.

Olaparib Addition to Maintenance Bevacizumab Therapy in Ovarian Carcinoma With BRCA-Like Genomic Aberrations.

Importance: Testing for homologous recombination deficiency is required for the optimal treatment of high-grade epithelial ovarian cancer. The search for accurate biomarkers is ongoing. Objective: To investigate whether progression-free survival (PFS) and overall survival (OS) of patients with high-grade epithelial ovarian cancer treated with maintenance olaparib or placebo differed between patients with a tumor BRCA-like genomic profile and patients without a tumor BRCA-like profile. Design, Setting, and Participants: This cohort study was a secondary analysis of the PAOLA-1 randomized clinical trial that compared olaparib plus bevacizumab with placebo plus bevacizumab as maintenance treatment in patients with advanced high-grade ovarian cancer after a good response to first-line platinum with taxane chemotherapy plus bevacizumab, irrespective of germline or tumor BRCA1/2 mutation status. All patients with available tumor DNA were included in the analysis. The current analysis tested for an interaction between BRCA-like status and olaparib treatment on survival outcomes. The original trial was conducted between July 2015 and September 2017; at the time of data extraction for analysis in March 2022, a median follow-up of 54.1 months (IQR, 28.5-62.2 months) and a total follow-up time of 21 711 months was available, with 336 PFS and 245 OS events. Exposures: Tumor homologous recombination deficiency was assessed using the BRCA-like copy number aberration profile classifier. Myriad MyChoice CDx was previously measured. The trial was randomized between the olaparib and bevacizumab and placebo plus bevacizumab groups. Main Outcomes and Measures: This secondary analysis assessed hazard ratios (HRs) of olaparib vs placebo among biomarker strata and tested for interaction between BRCA-like status and olaparib treatment on PFS and OS, using Cox proportional hazards regression. Results: A total of 469 patients (median age, 60 [range 26-80] years) were included in this study. The patient cohort consisted of women with International Federation of Gynaecology and Obstetrics stage III (76%) high-grade serous (95%) ovarian cancer who had no evaluable disease or complete remission at initial or interval debulking surgery (76%). Thirty-one percent of the tumor samples (n = 138) harbored a pathogenic BRCA mutation, and BRCA-like classification was performed for 442 patients. Patients with a BRCA-like tumor had a longer PFS after olaparib treatment than after placebo (36.4 vs 18.6 months; HR, 0.49; 95% CI, 0.37-0.65; P < .001). No association of olaparib with PFS was found in patients with a non-BRCA-like tumor (17.6 vs 16.6 months; HR, 1.02; 95% CI, 0.68-1.51; P = .93). The interaction was significant (P = .004), and HRs and P values (for interaction) were similar in the relevant subgroups, OS, and multivariable analyses. Conclusions and Relevance: In this secondary analysis of the PAOLA-1 randomized clinical trial, patients with a BRCA-like tumor, but not those with a non-BRCA-like tumor, had a significantly longer survival after olaparib plus bevacizumab treatment than placebo plus bevacizumab treatment. Thus, the BRCA1-like classifier could be used as a biomarker for olaparib plus bevacizumab as a maintenance treatment.

Platform comparisons for identification of breast cancers with a BRCA-like copy number profile.

Previously, we employed bacterial artificial chromosome (BAC) array comparative genomic hybridization (aCGH) profiles from BRCA1 and -2 mutation carriers and sporadic tumours to construct classifiers that identify tumour samples most likely to harbour BRCA1 and -2 mutations, designated 'BRCA1 and -2-like' tumours, respectively. The classifiers are used in clinical genetics to evaluate unclassified variants, and patients for which no good quality germline DNA is available. Furthermore, we have shown that breast cancer patients with BRCA-like tumour aCGH profiles benefit substantially from platinum-based chemotherapy, potentially due to their inability to repair DNA double strand breaks (DSB), providing a further important clinical application for the classifiers. The BAC array technology has been replaced with oligonucleotide arrays. To continue clinical use of existing classifiers, we mapped oligonucleotide aCGH data to the BAC domain, such that the oligonucleotide profiles can be employed as in the BAC classifier. We demonstrate that segmented profiles derived from oligonucleotide aCGH show high correlation with BAC aCGH profiles. Furthermore, we trained a support vector machine score to objectify aCGH profile quality. Using the mapped oligonucleotide aCGH data, we show equivalence in classification of biologically relevant cases between BAC and oligonucleotide data. Furthermore, the predicted benefit of DSB inducing chemotherapy due to a homologous recombination defect is retained. We conclude that oligonucleotide aCGH data can be mapped to and used in the previously developed and validated BAC aCGH classifiers. Our findings suggest that it is possible to map copy number data from any other technology in a similar way.

Homologous Recombination Deficiency and Cyclin E1 Amplification Are Correlated with Immune Cell Infiltration and Survival in High-Grade Serous Ovarian Cancer.

BACKGROUND: How molecular profiles are associated with tumor microenvironment (TME) in high-grade serous ovarian cancer (HGSOC) is incompletely understood. Therefore, we analyzed the TME and molecular profiles of HGSOC and assessed their associations with overall survival (OS). METHODS: Patients with advanced-stage HGSOC treated in three Dutch hospitals between 2008-2015 were included. Patient data were collected from medical records. BRCA1/2 mutation, BRCA1 promotor methylation analyses, and copy number variations were used to define molecular profiles. Immune cells were assessed with immunohistochemical staining. RESULTS: 348 patients were categorized as BRCA mutation (BRCAm) (BRCAm or promotor methylation) (30%), non-BRCA mutated HRD (19%), Cyclin E1 (CCNE1)-amplification (13%), non-BRCAmut HRD and CCNE1-amplification (double classifier) (20%), and no specific molecular profile (NSMP) (18%). BRCAm showed highest immune cell densities and CCNE1-amplification lowest. BRCAm showed the most favorable OS (52.5 months), compared to non-BRCAmut HRD (41.0 months), CCNE1-amplification (28.0 months), double classifier (27.8 months), and NSMP (35.4 months). Higher immune cell densities showed a favorable OS compared to lower, also within the profiles. CD8+, CD20+, and CD103+ cells remained associated with OS in multivariable analysis. CONCLUSIONS: Molecular profiles and TME are associated with OS. TME differs per profile, with higher immune cell densities showing a favorable OS, even within the profiles. HGSOC does not reflect one entity but comprises different entities based on molecular profiles and TME.

Ovarian Cancer-Specific BRCA-like Copy-Number Aberration Classifiers Detect Mutations Associated with Homologous Recombination Deficiency in the AGO-TR1 Trial.

PURPOSE: Previously, we developed breast cancer BRCA1-like and BRCA2-like copy-number profile shrunken centroid classifiers predictive for mutation status and response to therapy, targeting homologous recombination deficiency (HRD). Therefore, we investigated BRCA1- and BRCA2-like classification in ovarian cancer, aiming to acquire classifiers with similar properties as those in breast cancer.Experimental Design: We analyzed DNA copy-number profiles of germline BRCA1- and BRCA2-mutant ovarian cancers and control tumors and observed that existing breast cancer classifiers did not sufficiently predict mutation status. Hence, we trained new shrunken centroid classifiers on this set and validated them in the independent The Cancer Genome Atlas dataset. Subsequently, we assessed BRCA1/2-like classification and obtained germline and tumor mutation and methylation status of cancer predisposition genes, among them several involved in HR repair, of 300 ovarian cancer samples derived from the consecutive cohort trial AGO-TR1 (NCT02222883). RESULTS: The detection rate of the BRCA1-like classifier for BRCA1 mutations and promoter hypermethylation was 95.6%. The BRCA2-like classifier performed less accurately, likely due to a smaller training set. Furthermore, three quarters of the BRCA1/2-like tumors could be explained by (epi)genetic alterations in BRCA1/2, germline RAD51C mutations and alterations in other genes involved in HR. Around half of the non-BRCA-mutated ovarian cancer cases displayed a BRCA-like phenotype. CONCLUSIONS: The newly trained classifiers detected most BRCA-mutated and methylated cancers and all tumors harboring a RAD51C germline mutations. Beyond that, we found an additional substantial proportion of ovarian cancers to be BRCA-like.

Response of metastatic mouse invasive lobular carcinoma to mTOR inhibition is partly mediated by the adaptive immune system.

Effective treatment of invasive lobular carcinoma (ILC) of the breast is hampered by late detection, invasive growth, distant metastasis, and poor response to chemotherapy. Phosphoinositide 3-kinase (PI3K) signaling, one of the major druggable oncogenic signaling networks, is frequently activated in ILC. We investigated treatment response and resistance to AZD8055, an inhibitor of mammalian target of rapamycin (mTOR), in the K14-cre;Cdh1Flox/Flox;Trp53Flox/Flox (KEP) mouse model of metastatic ILC. Inhibition of mTOR signaling blocked the growth of primary KEP tumors as well as the progression of metastatic disease. However, primary tumors and distant metastases eventually acquired resistance after long-term AZD8055 treatment, despite continued effective suppression of mTOR signaling in cancer cells. Interestingly, therapeutic responses were associated with increased expression of genes related to antigen presentation. Consistent with this observation, increased numbers of tumor-infiltrating major histocompatibility complex class II-positive (MHCII+) immune cells were observed in treatment-responsive KEP tumors. Acquisition of treatment resistance was associated with loss of MHCII+ cells and reduced expression of genes related to the adaptive immune system. The therapeutic efficacy of mTOR inhibition was reduced in Rag1-/- mice lacking mature T and B lymphocytes, compared to immunocompetent mice. Furthermore, therapy responsiveness could be partially rescued by transplanting AZD8055-resistant KEP tumors into treatment-naïve immunocompetent hosts. Collectively, these data indicate that the PI3K signaling pathway is an attractive therapeutic target in invasive lobular carcinoma, and that part of the therapeutic effect of mTOR inhibition is mediated by the adaptive immune system.

Frequent Homologous Recombination Deficiency in High-grade Endometrial Carcinomas.

PURPOSE: The elevated levels of somatic copy-number alterations (SCNAs) in a subset of high-risk endometrial cancers are suggestive of defects in pathways governing genome integrity. We sought to assess the prevalence of homologous recombination deficiency (HRD) in endometrial cancers and its association with histopathologic and molecular characteristics. EXPERIMENTAL DESIGN: Fresh tumor tissue was prospectively collected from 36 endometrial cancers, and functional HRD was examined by the ability of replicating tumor cells to accumulate RAD51 protein at DNA double-strand breaks (RAD51 foci) induced by ionizing radiation. Genomic alterations were determined by next-generation sequencing and array comparative genomic hybridization/SNP array. The prevalence of BRCA-associated genomic scars, a surrogate marker for HRD, was determined in the The Cancer Genome Atlas (TCGA) endometrial cancer cohort. RESULTS: Most endometrial cancers included in the final analysis (n = 25) were of non-endometrioid (52%), grade 3 (60%) histology, and FIGO stage I (72%). HRD was observed in 24% (n = 6) of cases and was restricted to non-endometrioid endometrial cancers (NEEC), with 46% of NEECs being HRD compared with none of the endometrioid endometrial cancers (EEC, P = 0.014). All but 1 of the HRD cases harbored either a pathogenic BRCA1 variant or high somatic copy-number (SCN) losses of HR genes. Analysis of TCGA cases supported these results, with BRCA-associated genomic scars present in up to 48% (63/132) of NEEC versus 12% (37/312) of EEC (P < 0.001). CONCLUSIONS: HRD occurs in endometrial cancers and is largely restricted to non-endometrioid, TP53-mutant endometrial cancers. Evaluation of HRD may help select patients that could benefit from treatments targeting this defect, including platinum compounds and PARP inhibitors.

EZH2 Is Overexpressed in BRCA1-like Breast Tumors and Predictive for Sensitivity to High-Dose Platinum-Based Chemotherapy.

PURPOSE: BRCA1-deficient breast cancers carry a specific DNA copy-number signature ("BRCA1-like") and are hypersensitive to DNA double-strand break (DSB) inducing compounds. Here, we explored whether (i) EZH2 is overexpressed in human BRCA1-deficient breast tumors and might predict sensitivity to DSB-inducing drugs; (ii) EZH2 inhibition potentiates cisplatin efficacy in Brca1-deficient murine mammary tumors. EXPERIMENTAL DESIGN: EZH2 expression was analyzed in 497 breast cancers using IHC or RNA sequencing. We classified 370 tumors by copy-number profiles as BRCA1-like or non-BRCA1-like and examined its association with EZH2 expression. Additionally, we assessed BRCA1 loss through mutation or promoter methylation status and investigated the predictive value of EZH2 expression in a study population of breast cancer patients treated with adjuvant high-dose platinum-based chemotherapy compared with standard anthracycline-based chemotherapy. To explore whether EZH2 inhibition by GSK126 enhances sensitivity to platinum drugs in EZH2-overexpressing breast cancers we used a Brca1-deficient mouse model. RESULTS: The highest EZH2 expression was found in BRCA1-associated tumors harboring a BRCA1 mutation, BRCA1-promoter methylation or were classified as BRCA1 like. We observed a greater benefit from high-dose platinum-based chemotherapy in BRCA1-like and non-BRCA1-like patients with high EZH2 expression. Combined treatment with the EZH2 inhibitor GSK126 and cisplatin decreased cell proliferation and improved survival in Brca1-deficient mice in comparison with single agents. CONCLUSIONS: Our findings demonstrate that EZH2 is expressed at significantly higher levels in BRCA1-deficient breast cancers. EZH2 overexpression can identify patients with breast cancer who benefit significantly from intensified DSB-inducing platinum-based chemotherapy independent of BRCA1-like status. EZH2 inhibition improves the antitumor effect of platinum drugs in Brca1-deficient breast tumors in vivo.

Immune induction strategies in metastatic triple-negative breast cancer to enhance the sensitivity to PD-1 blockade: the TONIC trial.

The efficacy of programmed cell death protein 1 (PD-1) blockade in metastatic triple-negative breast cancer (TNBC) is low1-5, highlighting a need for strategies that render the tumor microenvironment more sensitive to PD-1 blockade. Preclinical research has suggested immunomodulatory properties for chemotherapy and irradiation6-13. In the first stage of this adaptive, non-comparative phase 2 trial, 67 patients with metastatic TNBC were randomized to nivolumab (1) without induction or with 2-week low-dose induction, or with (2) irradiation (3 × 8 Gy), (3) cyclophosphamide, (4) cisplatin or (5) doxorubicin, all followed by nivolumab. In the overall cohort, the objective response rate (ORR; iRECIST14) was 20%. The majority of responses were observed in the cisplatin (ORR 23%) and doxorubicin (ORR 35%) cohorts. After doxorubicin and cisplatin induction, we detected an upregulation of immune-related genes involved in PD-1-PD-L1 (programmed death ligand 1) and T cell cytotoxicity pathways. This was further supported by enrichment among upregulated genes related to inflammation, JAK-STAT and TNF-α signaling after doxorubicin. Together, the clinical and translational data of this study indicate that short-term doxorubicin and cisplatin may induce a more favorable tumor microenvironment and increase the likelihood of response to PD-1 blockade in TNBC. These data warrant confirmation in TNBC and exploration of induction treatments prior to PD-1 blockade in other cancer types.

Publisher Correction: Immune induction strategies in metastatic triple-negative breast cancer to enhance the sensitivity to PD-1 blockade: the TONIC trial.

In the version of this article originally published, there was an error in Fig. 3j. A label on the heatmap read "TGF-α signaling via NF-κB". It should have read "TNF-α signaling via NF-κB". The error has been corrected in the HTML and PDF versions of this article.