Purpose: Pancreatic ductal adenocarcinoma (PDA) is rarely cured, and single-agent immune checkpoint inhibition has not demonstrated clinical benefit despite the presence of large numbers of CD8+ T cells. We hypothesized that tumor-infiltrating CD8+ T cells harbor latent anti-tumor activity that can be reactivated using combination immunotherapy. Experimental Design: Preserved human PDA specimens were analyzed using multiplex immunohistochemistry (IHC) and T cell receptor (TCR) sequencing. Fresh tumor was treated in organotypic slice culture to test the effects of combination PD-1 and CXCR4 blockade. Slices were analyzed using IHC, flow cytometry and live fluorescent microscopy to assess tumor kill, in addition to T cell expansion and mobilization. Results: Multiplex IHC demonstrated fewer CD8+ T cells in juxtatumoral stroma containing carcinoma cells than in stroma devoid of them. Using TCR sequencing, we found clonal expansion in each tumor; high frequency clones had multiple DNA rearrangements coding for the same amino acid binding sequence, which suggests response to common tumor antigens. Treatment of fresh human PDA slices with combination PD-1 and CXCR4 blockade led to increased tumor cell death concomitant with lymphocyte expansion. Live microscopy after combination therapy demonstrated CD8+ T cell migration into the juxtatumoral compartment and rapid increase in tumor cell apoptosis. Conclusion: Endogenous tumor-reactive T cells are present within the human PDA tumor microenvironment and can be reactivated by combined blockade of PD-1 and CXCR4. This provides a new basis for the rational selection of combination immunotherapy for PDA.

Purpose This study examines cell-surface ROR1 expression in human tumors and normal tissues. ROR1 is considered a promising target for cancer therapy due to putative tumor-specific expression and multiple groups are developing antibodies and/or chimeric antigen receptor-modified T cells to target ROR1. On-target, off-tumor toxicity is a challenge for most non-mutated tumor antigens, however prior studies suggest that ROR1 is absent on most normal tissues. Experimental Design Our studies show that published antibodies lack sensitivity to detect endogenous levels of cell-surface ROR1 by immunohistochemistry (IHC) in FFPE tissues. We developed a ROR1-specific monoclonal antibody (mAb) targeting the carboxy-terminus of ROR1, and evaluated its specificity and sensitivity in IHC. Results The 6D4 mAb is a sensitive and specific reagent to detect cell-surface ROR1 by IHC. The data shows that ROR1 is homogenously expressed on a subset of ovarian cancer, triple negative breast cancer and lung adenocarcinomas. Contrary to previous findings, we found ROR1 is expressed on several normal tissues including parathyroid, pancreatic islets and regions of the esophagus, stomach and duodenum. The 6D4 mAb recognizes rhesus ROR1, and ROR1 expression was similar in human and macaque tissues suggesting that the macaque is a suitable model to evaluate safety of ROR1 targeted therapies. Conclusions ROR1 is a promising immunotherapeutic target in many epithelial tumors, however high cell-surface ROR1 expression in multiple normal tissues raises concerns for on-target off-tumor toxicities. Clinical translation of ROR1 targeted therapies warrants careful monitoring of toxicities to normal organs, and may require strategies to ensure patient safety.

Pancreatic ductal adenocarcinoma (PDA) remains a deadly disease that is rarely cured, despite many recent successes with immunotherapy for other malignancies. As the human disease is heavily infiltrated by effector T cells, we postulated that accurately modeling the PDA immune microenvironment would allow us to study mechanisms of immunosuppression that could be overcome for therapeutic benefit. Using viable precision-cut slices from fresh PDA, we developed an organotypic culture system for this purpose. We confirmed that cultured slices maintain their baseline morphology, surface area, and microenvironment after at least 6 d in culture, and demonstrated slice survival by MTT assay and by immunohistochemistry staining with Ki-67 and cleaved-Caspase-3 antibodies. Immune cells, including T cells (CD3+, CD8+, and FOXP3+) and macrophages (CD68+, CD163+ and HLA-DR+), as well as stromal myofibroblasts (αSMA+) were present throughout the culture period. Global profiling of the PDA proteome before and after 6 d slice culture indicated that the majority of the immunological proteins identified remain stable during the culture process. Cytotoxic effects of drug treatment (staurosporine, STS and cycloheximide, CHX) on PDA slices culture confirmed that this system can be used to assess functional response and cell survival following drug treatment in both a treatment time- and dose-dependent manner. Using multicolor immunofluorescence, we stained live slices for both cancer cells (EpCAM+) and immune cells (CD11b+ and CD8+). Finally, we confirmed that autologous CFSE-labeled splenocytes readily migrate into co-cultured tumor slices. Thus, our present study demonstrates the potential to use tumor slice cultures to study the immune microenvironment of PDA.

The 2013 CAP/ASCO HER2 Testing Guidelines Update modified HER2 FISH categories such that some cases with 'monosomy', 'co-amplification/polysomy', low-level increased HER2 signals or clustered heterogeneity now are considered amplified or equivocal. This study examines the frequency and clinico-pathologic characteristics of breast cancers with equivocal or 'non-classical' HER2 FISH results. Breast cancers (2001-2014) with HER2 FISH results, HER2 immunohistochemistry, ER, grade, and age from three institutions (Stanford, UCSF, UWMC) were collected. HER2 FISH was interpreted using the updated recommendations. Amplified cases with non-classical results were grouped into the following categories: (1) 'monosomy' (ratio ≥2.0, mean HER2/cell<4.0); (2) 'co-amplified' (ratio<2.0, mean HER2/cell ≥6.0); (3) 'low amplified' (ratio ≥2.0, mean HER2/cell 4.0-5.9). Heterogeneous cases with clustered HER2-positive cells were also included. Of 8068 cases, 5.2% were equivocal and 4.6% had a 'non-classical' HER2 amplified result; 1.4% 'monosomy', 0.8% 'co-amplified', 2.1% 'low amplified', and 0.3% clustered heterogeneity. These cancers had a high frequency of ER positive (80.4%), Nottingham grade 3 (52.1%) results. The highest percentage of grade 3 cancers (66.7%) and positive HER2 immunohistochemistry (31.7%) was in the 'co-amplified' group. The 'monosomy' group had the highest percent grade 1 cancers (13.3%) and was most frequently HER2 immunohistochemistry negative (30.1%). Equivocal cases had very similar characteristics to the 'low-amplified' category. Cases with non-classical HER2 amplification or equivocal results are typically ER positive, higher grade cancers. 'Co-amplified' cases have the highest frequencies of aggressive characteristics and 'monosomy' cases the highest frequencies of lower risk features. With little clinical outcomes data currently available on these non-classical HER2 results, these results support the current classification scheme for HER2 FISH, with case-by-case correlation with additional clinical-pathologic factors when evaluating whether to offer HER2-targeted therapies in these non-classical cases.

Congestive hepatopathy is a complication of right heart failure and chronically elevated right heart pressure. Histologic findings include sinusoidal dilatation, centrilobular hepatocellular plate atrophy, and fibrosis. We performed a validation study of a recently proposed scoring system (0 to 4 scale) for congestive hepatic fibrosis on 38 liver biopsies. Glutamine synthetase immunohistochemistry was also performed, and loss of centrizonal immunoreactivity correlated with increasing fibrosis score (P<0.01). Interobserver concordance for congestive hepatic fibrosis score based on Masson trichrome stain was initially fair (Fleiss κ=0.28, weighted concordance coefficient=0.60) and significantly improved (κ=0.40, weighted concordance coefficient=0.66) following a multiheaded microscope training session and inclusion of glutamine synthetase immunohistochemistry. Average congestive hepatic fibrosis score correlated with significantly higher right atrial pressure, severity of right atrial dilation, presence of right ventricular dilation, elevated serum alanine aminotransferase, platelet counts, prothrombin time, and model for end-stage liver disease score. In conclusion, the congestive hepatic fibrosis scoring system is reproducible among pathologists and correlates with clinical and laboratory markers of congestive hepatopathy.

Objective About a quarter of peripheral vein grafts fail due in part to intimal hyperplasia. The proliferative capacity and response to growth inhibitors of medial smooth muscle cells and adventitial fibroblasts in vitro were studied to test the hypothesis that intrinsic differences in cells of vein grafts are associated with graft failure. Methods Cells were grown from explants of the medial and adventitial layers of samples of vein grafts obtained at the time of implantation. Vein graft patency and function were monitored over the first 12 months using ankle pressures and Duplex ultrasound to determine vein graft status. Cells were obtained from veins from 11 patients whose grafts remained patent (non-stenotic) and from 7 patients whose grafts developed stenosis. Smooth muscle cells (SMCs) derived from media and fibroblasts derived from adventitia were growth arrested in serum-free medium and then stimulated with 1 μM sphingosine-1-phosphate (S1P), 10 nM thrombin, 10 ng/ml epidermal growth factor (EGF), 10 ng/ml platelet-derived growth factor-BB (PDGF-BB), PDGF-BB plus S1P, or PDGF-BB plus thrombin for determination of incorporation of [3H]-thymidine into DNA. Cells receiving PDGF-BB or thrombin were also treated with or without 100 μg/ml heparin, which is a growth inhibitor. Cells receiving thrombin were also treated with or without 100 nM AG1478, an EGF receptor kinase inhibitor. Results SMCs and fibroblasts from veins of patients that developed stenosis responded more to the growth factors, such as PDGF-BB alone or in combination with thrombin or S1P, than cells from veins of patients that remained patent (P=.012). In addition, while PDGF-BB-mediated proliferation of fibroblasts from grafts that remained patent was inhibited by heparin (P<.03), PDGF-BB-mediated proliferation of fibroblasts from veins that developed stenosis was not (P>.5). Conclusions Inherent differences in the proliferative response of vein graft cells to PDGF-BB and heparin may explain, in part, the variability among patients regarding long term patency of vein grafts.

4014 Background: PC is characterized by DNA Damage Repair (DDR) deficiencies, including in BRCA1/2, ATM, and FANC genes. Given preclinical synergism between veliparib with irinotecan, safety and preliminary efficacy, we designed a randomized phase II study of mFOLFIRI (no 5-FU bolus) + veliparib vs FOLFIRI alone for 2nd line mPC patients (pts). Methods: Eligible pts had mPC, adequate organ function, ECOG PS 0-1, and 1 prior non-irinotecan systemic therapy.143 pts were to be randomized (1:1) to veliparib vs control. Primary endpoint was overall survival (OS). All pts had blood and tumor biopsies at baseline to assess germline and somatic BRCA1/2 mutations (integrated), and homologous recombination (HR) or DDR biomarkers (exploratory). Results: 123 pts were accrued between 09/2016 to 12/2017, and 108 were included in this analysis. 117 pts were biomarker evaluable: 109 blood/106 tumors. 11 cancers (9%) had HR deficiency (HRD), including 4 germline ( BRCA1, BRCA2, ATM) and 7 somatic mutations ( BRCA2, PALB2, ATM, CDK12). Additional 24 cancers (20%) had germline (n = 11, e.g., FANC, BLM, SLX4, CHEK2) or somatic mutations (n = 13, e.g., FANC, BLM, POLD1, RIF1, MSH2, MSH6) in other DNA repair genes, not classified as HRD. A planned interim futility analysis at 35% of expected PFS events determined the veliparib arm was unlikely to be superior to control. Most common grade 3/4 treatment related toxicities were neutropenia (33% vs 20%), fatigue (19% vs 4%), and nausea (11% vs 4%), for veliparib vs control. Treatment exposure was similar for veliparib vs control: median 4 cycles (range 1-31 vs 1-32). Median OS was 5.1 vs 5.9 mos (HR 1.3, 95%CI 0.9-2.0, p = 0.21), and median PFS was 2.1 vs 2.9 mos (HR 1.5, 95%CI 1.0-2.2, p = 0.05) for veliparib vs control arms, respectively. Correlations of gene mutations and signatures with efficacy outcomes will be presented. Conclusions: Nearly 30% of mPC pts had DNA repair gene abnormalities, including 9% with HRD. Veliparib increased toxicity and did not improve OS when added to mFOLFIRI in biomarker unselected pts. BRCA1/2 and DDR biomarkers will be correlated with efficacy to inform patient selection for future PARP inhibitor clinical trials. Clinical trial information: NCT02890355.

The prevalence of clarithromycin resistance detected in this region exceeds 20%, indicating that standard triple therapy should not be the first-line antibiotic treatment for H. pylori infection. Culture-free assays for detecting clarithromycin resistance mutations can be performed on archived tissue samples and will aid in informing tailored treatment for effective H. pylori eradication.