Citations

Background and Purpose— Nearly 30% of large vessel occlusion acute ischemic stroke clots are from an unknown source. We assessed histological clot composition in a series of patients with large vessel occlusion and investigated correlations between clot composition and stroke pathogenesis. Methods— As part of the multi-institutional STRIP registry (Stroke Thromboembolism Registry of Imaging and Pathology), consecutive emboli retrieved during mechanical thrombectomy were stained using Martius Scarlett Blue and analyzed using machine learning software. We assessed proportions of red blood cells, fibrin, platelets, and white blood cells. Correlations between clot components and stroke pathogenesis (large artery atherosclerosis, cardioembolism, and stroke of undetermined pathogenesis) were assessed using SPSS22. Results— One hundred five patients were included. The proportion of platelet-rich clots (55.0% versus 21.2%; P =0.005) and percentage of platelet content (22.1±4.2% versus 13.9±14.2%; P =0.03) was significantly higher in the large artery atherosclerosis group compared with the cardioembolic group. The proportion of platelet-rich clots (50.0% versus 21.2%; P =0.024) was also significantly higher in the cryptogenic group compared with cardioembolic cases. Large artery atherosclerosis and cryptogenic cases had a similar proportion of platelet-rich clots (55.0% versus 50.0%; P =0.636). There was no significant difference between stroke pathogenesis and the other major clot components. Conclusions— High platelet content of emboli is associated with a large artery atherosclerosis etiology of large vessel occlusion.

5518 Background: Platinum resistant ovarian cancer (OC) remains a therapeutic challenge. High grade serous OC (HGSOC) harbors TP53 mutations leading to increased dependency on S- and G2-phase checkpoints. Wee1 inhibition with Adavosertib (AZD 1775) (A) induces G2 checkpoint escape. Gemcitabine (G) is an antimetabolite therapy and blocks the progression of cells through the G1/S phase. We hypothesized that combining G+A would be synergistic and overcome resistance. Methods: We conducted a multicentre double-blind 2:1 randomized phase 2 trial to assess the progression free survival (PFS) in women with recurrent platinum-resistant/refractory HGSOC receiving G+A or G+placebo (P) (NCT02151292). Eligibility required measurable disease and feasibility of paired tumor biopsies; no limitation in prior lines of therapy. Non HGSOC histologic subtypes were enrolled in a separate non-randomized exploratory cohort. A/P was given orally at 175mg QD on D1-2, D8-9 and D15-16 with G 1000mg/m² IV D1, D8 and D15 in a 28-day cycle until progression or unacceptable AE. Tumor staging was scheduled every 8 weeks. TP53 mutations were analyzed on archival tissue with Sanger sequencing, TAm-Seq and IHC. TP53 mutation will be also assessed in circulating tumor DNA (ctDNA). Whole exome and RNA sequencing were performed on paired tumor tissues. Results: 124 patients (pts) with median of 3 prior lines of therapy (range 1-10) from 12 centres across Canada and US were enrolled between Sep 2014 to May 2018, with 99 pts randomized (65 in Arm G+A and 34 in G+P). 5 pts were ineligible; 64 pts have died. The median follow-up was 14.3 months. Main related AE was hematologic toxicity (Anemia G≥3: 31% in G+A vs 18% in G+P; Thrombocytopenia G≥3: 31% vs 6%; Neutropenia G≥3: 62% vs 30%). PFS was significantly improved from 3.0 to 4.6 months (HR 0.56 (95%CI: 0.35-0.90, p=0.015 Log rank). There was a significant improvement in overall survival (OS) from 7.2 to 11.5 months (HR 0.56 (95%CI: 0.34-0.92, P=0.022). Partial response by RECIST 1.1 was observed in 13 (21%) and 1 (3%) pts for Arms G+A and G+P, respectively (p=0.02). From the 25 pts in the exploratory cohort, 3 (12%) partial responses were observed. Final results will be reported at the meeting. Conclusion: Addition of adavosertib to gemcitabine in women with platinum resistant/refractory OC improved response rate, PFS and OS with manageable toxicity. Clinical trial information: NCT02151292.

3599 Background: Existing tools for post-treatment CRC surveillance and monitoring are insensitive and expensive. MDMs are broadly informative for early detection of CRC but have not been extensively studied for disease monitoring. As a first step, we sought to assess the concordance of novel CRC-associated MDMs in pCRC and mCRC. Methods: A panel of 14 MDMs previously identified to be highly discriminant for pCRC was selected on the basis of high median fold-change of MDM levels relative to buffy coat (682 (IQR: 132-19347)). Surgically resected pCRC and paired mCRC were identified from institutional pathology databases. Quantitative methylation-specific PCR was used to assay MDMs. 30 paired samples per metastatic subtype were calculated to be sufficient. MDM levels were compared using two-sample and paired Wilcoxon rank sum tests. Results: 87 patients with paired pCRC and mCRC including 57 synchronous and 30 metachronous metastases were included. 41/87 (47%) had neoadjuvant and 59/87 (68%) had adjuvant chemotherapy. All synchronous metastases were to liver. Metachronous metastases were to liver in 19/30 (63%) and to lung in 11/30 (37%). The levels of 14 selected MDMs were remarkably similar between paired pCRC and mCRC (Table). Individual MDM levels and the average level of all MDMs combined were not significantly different ( p> 0.0018 by Bonferroni correction). Conclusions: MDM levels are highly concordant in pCRC and mCRC. Thus, MDMs discovered from pCRC should be further studied for non-invasive surveillance after surgical resection and monitoring of treatment response in mCRC. [Table: see text]

529 Background: The effect of metformin on sex hormones (SHs) levels that may impact breast cancer (BC) outcome, is unclear. We evaluated the effect of metformin on SHs in a subgroup of women enrolled in the placebo-controlled MA.32 trial, a phase III randomized study of nondiabetic subjects with T1-3, N0-3 BC randomized to receive metformin 850 mg po bid or placebo for 5 years. Methods: Our substudy was conducted on the group of post-menopausal women with estrogen receptor (ER) and progesterone receptor (PR) negative BC and not receiving endocrine treatment enrolled in the trial. Post-menopausal was defined as prior bilateral oophorectomy or > 12 months since last menses without prior hysterectomy. Fasting blood and adherence to study drug at baseline and 6 months was required. Sex hormone binding globulin (SHBG), free testosterone and estradiol serum levels were evaluated using Roche Modular competitive ECLIA (electrochemiluminescense immunoassay). We compared change from baseline to 6 months in estradiol, SHBG and free testosterone between study arms using Wilcoxon sum rank tests and regression models to adjust for baseline BMI and weight change. Results: 304 women were eligible, 135 metformin vs 169 placebo; tumor stage and prior (neo)adjuvant chemotherapy (98% in both arms) and HER2 targeted treatment were well balanced between arms. At baseline mean age was 58.2±6.9 vs 57.6±7.9 years, mean BMI 26.9±4.9 vs 28.6±6.2 Kg/m2, median estradiol 29.82 vs 31.01 pmol/L, SHBG 80.6 vs 73.7 nmol/L and free testosterone 0.02 vs 0.03 nmol/L in metformin vs placebo patients, respectively. In univariable analysis, median estradiol decreased significantly between baseline and 6 months on the metformin vs placebo arm (-4.81 vs 0 pmol/L, p = < 0.0001); this difference remained significant after controlling for baseline BMI (p = 0.0001) and weight change (mean weight change -1.8±3.5 vs 0.4±3.5 Kg, p = < 0.0001 for metformin vs placebo respectively) between baseline and 6 months (p = 0.0007). In contrast, there was no significant change in SHBG or free testosterone (median change SHBG -5.5 vs -5.9 nmol/L, p = 0.33; median change free testosterone 0 vs 0 nmol/L, p = 0.33 for metformin vs placebo respectively). Conclusions: Metformin lowered estradiol levels, independent of weight change in non-diabetic post-menopausal women with ER and PR negative BC enrolled onto MA.32 trial. This observation suggests a new metformin action that has potential relevance to BC management.

A reduction in intestinal barrier function is currently believed to play an important role in pathogenesis of many diseases, as it facilitates passage of injurious factors such as lipopolysaccharide, peptidoglycan, whole bacteria, and other toxins to traverse the barrier to damage the intestine or enter the portal circulation. Currently available evidence in animal models and in vitro systems has shown that certain dietary interventions can be used to reinforce the intestinal barrier to prevent the development of disease. The relevance of these studies to human health is unknown. Herein, we define the components of the intestinal barrier, review available modalities to assess its structure and function in humans, and review the available evidence in model systems or perturbations in humans that diet can be used to fortify intestinal barrier function. Acknowledging the technical challenges and the present gaps in knowledge, we provide a conceptual framework by which evidence could be developed to support the notion that diet can reinforce human intestinal barrier function to restore normal function and potentially reduce the risk for disease. Such evidence would provide information on the development of healthier diets and serve to provide a framework by which federal agencies such as the US Food and Drug Administration can evaluate evidence linking diet with normal human structure/function claims focused on reducing risk of disease in the general public.

AbstractAnaplastic large cell lymphomas (ALCLs) represent a relatively common group of T-cell non-Hodgkin lymphomas (T-NHLs) that are unified by similar pathologic features but demonstrate marked genetic heterogeneity. ALCLs are broadly classified as being anaplastic lymphoma kinase (ALK)+ or ALK−, based on the presence or absence of ALK rearrangements. Exome sequencing of 62 T-NHLs identified a previously unreported recurrent mutation in the musculin gene, MSCE116K, exclusively in ALK− ALCLs. Additional sequencing for a total of 238 T-NHLs confirmed the specificity of MSCE116K for ALK− ALCL and further demonstrated that 14 of 15 mutated cases (93%) had coexisting DUSP22 rearrangements. Musculin is a basic helix-loop-helix (bHLH) transcription factor that heterodimerizes with other bHLH proteins to regulate lymphocyte development. The E116K mutation localized to the DNA binding domain of musculin and permitted formation of musculin–bHLH heterodimers but prevented their binding to authentic target sequence. Functional analysis showed MSCE116K acted in a dominant-negative fashion, reversing wild-type musculin-induced repression of MYC and cell cycle inhibition. Chromatin immunoprecipitation–sequencing and transcriptome analysis identified the cell cycle regulatory gene E2F2 as a direct transcriptional target of musculin. MSCE116K reversed E2F2-induced cell cycle arrest and promoted expression of the CD30–IRF4–MYC axis, whereas its expression was reciprocally induced by binding of IRF4 to the MSC promoter. Finally, ALCL cells expressing MSCE116K were preferentially targeted by the BET inhibitor JQ1. These findings identify a novel recurrent MSC mutation as a key driver of the CD30–IRF4–MYC axis and cell cycle progression in a unique subset of ALCLs.

Abstract Soft tissue sarcomas are a rare and heterogeneous group of malignancies that present significant diagnostic and therapeutic challenges. Patient stratification based on tumor aggressiveness and early therapeutic response based on quantitative imaging may improve prediction of treatment response and the evaluation of new treatment strategies in clinical trials. The purpose of this pilot study was to determine the technical feasibility of magnetic resonance elastography (MRE) and dynamic contrast-enhanced (DCE) MRI for the evaluation of sarcoma stiffness and perfusion in 9 patients with histologically confirmed sarcoma. Additionally, we assessed the feasibility of utilizing MRE and DCE-MRI for the early evaluation of response to radiation therapy in 4 patients to determine the utility of further evaluation in a larger cohort study. Tumor size, stiffness, and perfusion parameters all decreased from baseline at the time of the pre-surgery or follow-up MRI, and results were compared to pathology or conventional imaging. MRE and DCE-MRI may be useful for the quantitative evaluation of tumor stiffness and perfusion, and therapy response assessment in soft tissue sarcomas.