Citations

Abstract Dysregulation of estrogen receptor gene (ESR1) is an established mechanism of inducing endocrine therapy resistance. We previously discovered a chromosomal translocation event generating an estrogen receptor gene fused in-frame to C-terminal sequences of YAP1 (ESR1-YAP1) that contributed to endocrine therapy resistance in estrogen receptor positive (ER+) breast cancer models. This current study compares functional and pharmacological properties of additional ESR1 gene fusion events of both early stage (ESR1-NOP2) and advanced endocrine therapy resistant (ESR1-YAP1 and ESR1-PCDH11x) breast cancers. The YAP1 and PCDH11x fusions conferred estrogen-independent and fulvestrant-resistant growth in T47D, an ER+ breast cancer cell line in vitro and in vivo, in contrast to the NOP2 fusion which was sensitive to hormone deprivation. Immunohistochemical (IHC) staining of mouse lungs revealed significantly higher numbers of micrometastatic ER+ cells from the T47D tumors expressing the YAP1 and PCDH11x fusions than YFP control and NOP2 fusion. Estrogen response element (ERE) reporter and pull down assays revealed that although all ESR1 fusions studied bound EREs, only the YAP1 and PCDH11x caused ERE activation. Cell lines containing these “canonical” ESR1 fusions upregulated expression of ER responsive genes such as TFF1 and GREB1 in hormone deprived conditions. In contrast, the NOP2 fusion neither induced ERE activity nor upregulated TFF1 and GREB1 gene expression. The proliferative ability of canonical fusion-containing T47D cells was inhibited by palbociclib, a CDK4/6 inhibitor, in a dose-dependent manner. In vivo growth of patient-derived xenograft tumors naturally harboring the ESR1-YAP1 fusion (WHIM18) was significantly reduced in mice fed palbociclib-containing chow. Mice transplanted with WHIM18 also formed lung micrometastases, with an ER IHC staining pattern similar to lungs from YAP1 and PCDH11x fusion expressing T47D xenografts. In conclusion, in-frame ERE activating canonical fusions occur in end-stage, drug resistant, advanced breast cancer and can be added to ESR1 point mutations as a class of somatic mutation that may cause acquired resistance. Endocrine therapy resistant growth induced by these fusions can be treated with CDK4/6 inhibition, using an FDA approved drug, palbociclib, which could potentially improve outcomes in patients with ESR1 translocated tumors. Citation Format: Jonathan T. Lei, Jieya Shao, Jin Zhang, Michael Iglesia, Doug W. Chan, Ryoichi Matsunuma, Xiaping He, Purba Singh, Yoshimasa Kosaka, Robert Crowder, Svasti Haricharan, Shyam Kavuri, Jeremy Hoog, Chanpheng Phommaly, Rodrigo Goncalves, Susana Romalho, Wei-Chu Lai, Oliver Hampton, Anna Rogers, Ethan Tobias, Poojan Parikh, Sherri Davies, Cynthia Ma, Vera Suman, Kelly Hunt, Mark Watson, Katherine A. Hoadley, Aubrey Thompson, Charles Perou, Chad J. Creighton, Chris Maher, Matthew J. Ellis. Estrogen receptor gene fusions drive endocrine therapy resistance in estrogen receptor positive breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1033. doi:10.1158/1538-7445.AM2017-1033

Aims Routine application of PD-L1 immunohistochemistry (IHC) in colorectal cancer (CRC) is limited due to lack of standardized scoring criteria, antibody clones, and intratumoral staining heterogeneity. We assessed PD-L1 protein expression on full face CRC tissue sections and applied two algorithms based on the published clinical trials that support the recent FDA approval for immune checkpoint inhibitors (ICPI) therapy in non-small cell lung cancer (NSCLC). Methods PD-L1/CD274 IHC (Roche/Ventana, clone SP142) was performed on representative tumour blocks from 52 mismatch repair-deficient (MMR-D) and 52 MMR-proficient (MMR-P) CRCs. Membranous PD-L1 expression was scored for the tumour cell (TC) and tumour-infiltrating immune cell (IC) components. PD-L1 positivity status was determined based on the published NSCLC clinical trials that utilized the Ventana SP142 assay. Hybrid capture-based comprehensive genomic profiling (CGP) was performed on a separate set of 2268 clinically advanced CRCs and the frequency of PD-L1/PD-L2 amplification was determined. Results PD-L1 expression in the TC and IC correlated with MMR-D (p=0.013, p<0.0001), T stage (p=0.036, p=0.0036) and clinical stage (p=0.022, p=0.0037). PD-L1 positivity status correlated with MMR-D by two algorithms. Five of 2268 (<1%) advansced CRCs demonstrated amplification of either the PD-L1 or PD-L2 genes by CGP. Conclusions PD-L1 expression in TC and IC is associated with advanced stage and MMR-D. PD-L1 positivity status by the published algorithm is associated with MMR-D. PD-L1 amplification is extremely uncommon in CRC. Evaluation of whole tissue section and incorporation of IC staining enhance the sensitivity to screen patients who may benefit from ICPI therapy.

Staff from the Mayo Clinic in the US and the Karolinska Institute in Sweden describe a joint transatlantic course intended to broaden the horizons of the next generation of researchers in the field of regenerative medicine.

Background Following pressure overload, compensatory concentric left ventricular remodeling ( CR ) variably transitions to eccentric remodeling ( ER ) and systolic dysfunction. Mechanisms responsible for this transition are incompletely understood. Here we leverage phenotypic variability in pressure overload–induced cardiac remodeling to test the hypothesis that altered mitochondrial homeostasis and calcium handling occur early in the transition from CR to ER , before overt systolic dysfunction. Methods and Results Sprague Dawley rats were subjected to ascending aortic banding, (n=68) or sham procedure (n=5). At 3 weeks post–ascending aortic banding, all rats showed CR (left ventricular volumes < sham). At 8 weeks post–ascending aortic banding, ejection fraction was increased or preserved but 3 geometric phenotypes were evident despite similar pressure overload severity: persistent CR , mild ER , and moderate ER with left ventricular volumes lower than, similar to, and higher than sham, respectively. Relative to sham, CR and mild ER phenotypes displayed increased phospholamban, S16 phosphorylation, reduced sodium‐calcium exchanger expression, and increased mitochondrial biogenesis/content and normal oxidative capacity, whereas moderate ER phenotype displayed decreased p‐phospholamban, S16, increased sodium‐calcium exchanger expression, similar degree of mitochondrial biogenesis/content, and impaired oxidative capacity with unique activation of mitochondrial autophagy and apoptosis markers ( BNIP 3 and Bax/Bcl‐2). Conclusions After pressure overload, mitochondrial biogenesis and function and calcium handling are enhanced in compensatory CR . The transition to mild ER is associated with decrease in mitochondrial biogenesis and content; however, the progression to moderate ER is associated with enhanced mitochondrial autophagy/apoptosis and impaired mitochondrial function and calcium handling, which precede the onset of overt systolic dysfunction.

Abstract Germline and somatic mutations in BRCA1 and BRCA2 (BRCA) confer PARP inhibitor sensitivity. Promoter hypermethylation is an alternate mechanism of gene down-regulation, and BRCA1 promoter methylation is relatively common in sporadic ovarian cancer. The clinical significance of BRCA1 methylation is less clear than for mutations, as the Cancer Genome Atlas (TCGA) and others have failed to show improved survival in ovarian carcinomas with BRCA1 methylation. No one has previously tested whether BRCA1 methylation confers in vivo sensitivity to PARP inhibitors in patients with ovarian cancer. ARIEL2 is a phase 2 study of the PARP inhibitor rucaparib in patients with recurrent platinum sensitive high-grade ovarian, peritoneal or fallopian tube carcinoma. At enrollment, ARIEL2 required pre-treatment tumor biopsies with the goal of developing tissue predictors of PARP inhibitor sensitivity other than BRCA mutations. The number of women with known germline mutations was capped at 15 patients in order to predominantly enroll BRCA wildtype cases. As presented at ASCO 2016, in cases with no BRCA mutations, a high fraction of genomic loss of heterozygosity (LOH) significantly predicted a better progression-free survival (the primary endpoint), longer duration of response, and a higher fraction of responders compared to cases with low LOH. We assessed BRCA1 and RAD51C promoter hypermethylation using methylation-sensitive polymerase chain reaction in paired archival and pre-treatment biopsies from patients on ARIEL2. Of 165 cases for which methylation analyses were completed, 21 (12.7%) were methylated at the BRCA1 promoter and four (2.4%) at the RAD51C promoter. Methylation of BRCA1 and RAD51C was mutually exclusive with mutation in BRCA or other homologous recombination genes. All four cases with RAD51C methylation and 15/19 (78.9%) with BRCA1 methylation were associated with high LOH. In 90 paired samples archival and pre-treatment tissues, RAD51C methylation was 100% concordant and BRCA1 methylation was highly concordant (p&lt;0·001). For 13 cases with BRCA1 methylation in the archival specimen, 4 (30·8%) were unmethylated in the paired pretreatment tumor, but for 77 unmethylated archival specimens, gain of methylation in the pretreatment biopsy was observed just once. Confirmed RECIST responses were seen in 52.4% (11/21) BRCA1 methylated and 75.0% (3/4) RAD51C methylated cases. In conclusion, BRCA1 and RAD51C methylation in ovarian carcinomas correlates with a high response rate to PARP inhibitors. If methylation was to be used as a predictor of PARP inhibitor sensitivity, it would need to be assessed in a pre-treatment (not archival) specimen. The loss of BRCA1 methylation in recurrent ovarian carcinoma, which was common even in these platinum sensitive cases, could explain why BRCA1 methylation is associated with similar survival to methylated cases, despite initial improved therapeutic sensitivity. Citation Format: Elizabeth Swisher, Maria Harrell, Kevin K. Lin, Clare Scott, Sandra Goble, Amit Oza, Robert L. Coleman, Gottfried Konecny, Anna V. Tinker, David M. O'Malley, Rebecca Kristeleit, Ling Ma, James Brenton, Katherine Bell-McGuinn, Ana Oaknin, Alexandra Leary, Elaina Mann, Heidi Giordano, Mitch Rapon, Iain McNeish, Scott H. Kaufmann. BRCA1 and RAD51C Promoter Hypermethylation Confer Sensitivity to PARP Inhibitors in Patients with Platinum Sensitive Ovarian Carcinoma [abstract]. In: Proceedings of the 11th Biennial Ovarian Cancer Research Symposium; Sep 12-13, 2016; Seattle, WA. Philadelphia (PA): AACR; Clin Cancer Res 2017;23(11 Suppl):Abstract nr AP28.

Summary Objective To validate predictive models for neural antibody positivity and immunotherapy response in epilepsy. Methods We conducted a retrospective study of epilepsy cases at Mayo Clinic (Rochester‐ MN ; Scottsdale‐ AZ , and Jacksonville‐ FL ) in whom autoimmune encephalopathy/epilepsy/dementia autoantibody testing profiles were requested (06/30/2014‐06/30/2016). An Antibody Prevalence in Epilepsy ( APE ) score, based on clinical characteristics, was assigned to each patient. Among patients who received immunotherapy, a Response to Immunotherapy in Epilepsy ( RITE ) score was assigned. Favorable seizure outcome was defined as >50% reduction of seizure frequency at the first follow‐up . Results Serum and cerebrospinal fluid (CSF) from 1,736 patients were sent to the Mayo Clinic Neuroimmunology Laboratory for neural autoantibody evaluation. Three hundred eighty‐seven of these patients met the diagnostic criteria for epilepsy. Central nervous system (CNS)–specific antibodies were detected in 44 patients. Certain clinical features such as new‐onset epilepsy, autonomic dysfunction, viral prodrome, faciobrachial dystonic seizures/oral dyskinesia, inflammatory CSF profile, and mesial temporal magnetic resonance imaging (MRI) abnormalities had a significant association with positive antibody results. A significantly higher proportion of antibody‐positive patients had an APE score ≥4 (97.7% vs. 21.6%, p < 0.01). Sensitivity and specificity of an APE score ≥4 to predict presence of specific neural auto‐antibody were 97.7% and 77.9%, respectively. In the subset of patients who received immunotherapy (77), autonomic dysfunction, faciobrachial dystonic seizures/oral dyskinesia, early initiation of immunotherapy, and presence of antibodies targeting plasma membrane proteins (cell‐surface antigens) were associated with favorable seizure outcome. Sensitivity and specificity of a RITE score ≥7 to predict favorable seizure outcome were 87.5% and 83.8%, respectively. Significance APE and RITE scores can aid diagnosis, treatment, and prognostication of autoimmune epilepsy. A PowerPoint slide summarizing this article is available for download in the Supporting Information section here .

Objective: High GATA2 expression has been associated with an increased risk of poor clinical outcomes after radical prostatectomy; however, this has not been studied in relation to risk of biochemical recurrence (BCR) after salvage radiation therapy (SRT) for recurrent prostate cancer after radical prostatectomy. Our aim was to evaluate the association between protein expression levels of GATA2 in primary prostate cancer tumour samples and the risk of BCR after SRT. Methods: 109 males who were treated with SRT were included. The percentage of cells with nuclear staining and GATA2 staining intensity were both measured. These two measures were multiplied together to obtain a GATA2 H-score (range 0–12) which was our primary GATA2 staining measure. Results: In unadjusted analysis, the risk of BCR was higher for patients with a GATA2 H-score &gt;4 (hazard ratio = 2.04, p = 0.033). In multivariable analysis adjusting for SRT dose, pre-SRT PSA, pathological tumour stage and Gleason score, this association weakened substantially (hazard ratio = 1.45, p = 0.31). This lack of an independent association with BCR appears to be the result of correlations between GATA2 H-score &gt;4 and higher pre-SRT PSA (p = 0.021), higher Gleason score (p = 0.044) and more severe pathological tumour stage (p = 0.068). Conclusion: Higher levels of GATA2 expression appear to be a marker of prostate cancer severity; however, these do not provide independent prognostic information regarding BCR beyond that of validated clinicopathological risk factors. Advances in knowledge: A higher GATA2 expression level appears to be correlated with known measures of prostate cancer severity and therefore is likely not an independent marker of outcome after SRT.