Maria Toki

A Quantitative Comparison of Antibodies to Programmed Cell Death 1 Ligand 1

Importance Assessment of PD-L1 (programmed cell death 1 ligand 1) expression by immunohistochemical analysis has been used as a predictive diagnostic test to identify responders and guide treatment in trials of the PD-1 (programmed cell death 1) axis inhibitors. The definition of PD-L1 positive lacks standardization, and prediction of response by immunohistochemical analysis is additionally limited by the subjective nature of this technique. Objective To examine whether PD-L1 antibody reagents are interchangeable by quantitatively comparing the expression of the PD-L1 protein. Design, Setting, and Participants In this immunohistochemistry standardization study, 30 randomly selected cases of lung cancer resected from January 1, 2008, through December 31, 2009, were obtained from Yale Pathology Archives with a range of expression of PD-L1. To test for protein measurement, rather than clinical utility, a PD-L1 index tissue microarray, including cell line and tissue controls, was used. The results were then validated on a commercially available, genetically defined PD-L1 engineered cell line array with a range of controlled protein-expressing cell lines using 6 monoclonal antibodies (SP142, E1L3N, 9A11, SP263, 22c3, and 28-8). Protein levels were measured by quantitative immunofluorescence and quantitative chromogenic assessment. Data analysis was performed from September 2015 through May 2016. Results Concordance between 4 antibodies revealed regression for tumor tissue cores (R2 = 0.42-0.91) and cell line cores (R2 = 0.83-0.97) by quantitative immunofluorescence in the PD-L1 index tissue microarray. All 6 antibodies had high levels of concordance (R2 = 0.76-0.99) when using chromogenic staining in isogenic cell lines. Conclusions and Relevance Because the antibodies are highly concordant, these results suggest that assays based on the use of these antibodies could yield concordant results. They further suggest that previously described differences in PD-L1 expression in tissue are independent of the antibody used and likely attributable to tumor heterogeneity, assay- or platform-specific variables, or other factors.

B7-H3 expression in NSCLC and its association with B7-H4, PD-L1 and Tumor Infiltrating Lymphocytes

Purpose: The immune checkpoint PD-1 and its receptor B7-H1 (PD-L1) are successful therapeutic targets in cancer but less is known about other B7 family members. Here, we determined the expression level of B7-H3 protein in non–small cell lung cancer (NSCLC) and evaluated its association with tumor-infiltrating lymphocytes (TIL), PD-L1, B7-H4, and major clinicopathologic characteristics is in 3 NSCLC cohorts. Experimental design: We used multiplexed automated quantitative immunofluorescence (QIF) to assess the levels of B7-H3, PD-L1, B7-H4, and TILs in 634 NSCLC cases with validated antibodies. Associations between the marker levels, major clinicopathologic variables and survival were analyzed. Results: Expression of B7-H3 protein was found in 80.4% (510/634) of the cases. High B7-H3 protein level (top 10 percentile) was associated with poor overall survival (P < 0.05). Elevated B7-H3 was consistently associated with smoking history across the 3 cohorts, but not with sex, age, clinical stage, and histology. Coexpression of B7-H3 and PD-L1 was found in 17.6% of the cases (112/634) and with B7-H4 in 10% (63/634). B7-H4 and PD-L1 were simultaneously detected only in 1.8% of NSCLCs (12/634). The expression of B7-H3 was not associated with the levels of CD3-, CD8-, and CD20-positive TILs. Conclusions: B7-H3 protein is expressed in the majority of NSCLCs and is associated with smoking history. High levels of B7-H3 protein have a negative prognostic impact in lung carcinomas. Coexpression of B7-H3 with PD-L1 and B7-H4 is relatively low, suggesting a nonredundant biological role of these targets. Clin Cancer Res; 23(17); 5202–9. ©2017 AACR.

Oncogenic EGFR Represses the TET1 DNA Demethylase to Induce Silencing of Tumor Suppressors in Cancer Cells

Oncogene-induced DNA methylation-mediated transcriptional silencing of tumor suppressors frequently occurs in cancer, but the mechanism and functional role of this silencing in oncogenesis are not fully understood. Here, we show that oncogenic epidermal growth factor receptor (EGFR) induces silencing of multiple unrelated tumor suppressors in lung adenocarcinomas and glioblastomas by inhibiting the DNA demethylase TET oncogene family member 1 (TET1) via the C/EBPα transcription factor. After oncogenic EGFR inhibition, TET1 binds to tumor suppressor promoters and induces their re-expression through active DNA demethylation. Ectopic expression of TET1 potently inhibits lung and glioblastoma tumor growth, and TET1 knockdown confers resistance to EGFR inhibitors in lung cancer cells. Lung cancer samples exhibited reduced TET1 expression or TET1 cytoplasmic localization in the majority of cases. Collectively, these results identify a conserved pathway of oncogenic EGFR-induced DNA methylation-mediated transcriptional silencing of tumor suppressors that may have therapeutic benefits for oncogenic EGFR-mediated lung cancers and glioblastomas.

Proof of the quantitative potential of immunofluorescence by mass spectrometry

Protein expression in formalin-fixed, paraffin-embedded patient tissue is routinely measured by Immunohistochemistry (IHC). However, IHC has been shown to be subject to variability in sensitivity, specificity and reproducibility, and is generally, at best, considered semi-quantitative. Mass spectrometry (MS) is considered by many to be the criterion standard for protein measurement, offering high sensitivity, specificity, and objective molecular quantification. Here, we seek to show that quantitative immunofluorescence (QIF) with standardization can achieve quantitative results comparable to MS. Epidermal growth factor receptor (EGFR) was measured by quantitative immunofluorescence in 15 cell lines with a wide range of EGFR expression, using different primary antibody concentrations, including the optimal signal-to-noise concentration after quantitative titration. QIF target measurement was then compared to the absolute EGFR concentration measured by Liquid Tissue-selected reaction monitoring mass spectrometry. The best agreement between the two assays was found when the EGFR primary antibody was used at the optimal signal-to-noise concentration, revealing a strong linear regression (R2=0.88). This demonstrates that quantitative optimization of titration by calculation of signal-to-noise ratio allows QIF to be standardized to MS and can therefore be used to assess absolute protein concentration in a linear and reproducible manner.

Spatially resolved and quantitative analysis of VISTA/PD-1H as a novel immunotherapy target in human non-small cell lung cancer

Purpose: Determine the localized expression pattern and clinical significance of VISTA/PD-1H in human non–small cell lung cancer (NSCLC). Experimental Design: Using multiplex quantitative immunofluorescence (QIF), we performed localized measurements of VISTA, PD-1, and PD-L1 protein in 758 stage I–IV NSCLCs from 3 independent cohorts represented in tissue microarray format. The targets were selectively measured in cytokeratin+ tumor epithelial cells, CD3+ T cells, CD4+ T-helper cells, CD8+ cytotoxic T cells, CD20+ B lymphocytes and CD68+ tumor-associated macrophages. We determined the association between the targets, clinicopathological/molecular variables and survival. Genomic analyses of lung cancer cases from TCGA were also performed. Results: VISTA protein was detected in 99% of NSCLCs with a predominant membranous/cytoplasmic staining pattern. Expression in tumor and stromal cells was seen in 21% and 98% of cases, respectively. The levels of VISTA were positively associated with PD-L1, PD-1, CD8+ T cells and CD68+ macrophages. VISTA expression was higher in T-lymphocytes than in macrophages; and in cytotoxic T cells than in T-helper cells. Elevated VISTA was associated with absence of EGFR mutations and lower mutational burden in lung adenocarcinomas. Presence of VISTA in tumor compartment predicted longer 5-year survival. Conclusions: VISTA is frequently expressed in human NSCLC and shows association with increased tumor-infiltrating lymphocytes, PD-1 axis markers, specific genomic alterations and outcome. These results support the immunomodulatory role of VISTA in human NSCLC and suggests its potential as therapeutic target. Clin Cancer Res; 24(7); 1562–73. ©2017 AACR.

EGFR-GRB2 Protein Colocalization Is a Prognostic Factor Unrelated to Overall EGFR Expression or EGFR Mutation in Lung Adenocarcinoma

Introduction EGFR is a therapeutic target in NSCLC for EGFR‐mutant patients. Proximity ligation assay (PLA) is a method to detect functional signaling associated protein complexes. Growth factor receptor bound protein 2 (GRB2) is an adaptor protein that binds to the phosphorylated residues of active EGFR. Interaction of EGFR and GRB2 correlates with active EGFR signaling and leads to activation of the MAPK/ERK pathway. Methods A PLA developed to detect EGFR‐GRB2 interaction was measured by quantitative immunofluorescence using Automated Quantitative Analysis technology. EGFR pathway activation was assessed in patients with NSCLC with different mutation status along with overall EGFR expression. Additionally, the PLA to detect EGFR‐GRB2 interaction was evaluated as a prognostic marker in two cohorts of patients with lung adenocarcinoma. Results The PLA to detect EGFR‐GRB2 interaction was unrelated to overall EGFR expression or mutation in a series of patients with NSCLC with known mutation status. EGFR‐mutant (p = 0.04) and EGFR/KRAS wild‐type tumors (p = 0.0049) had significantly higher EGFR pathway activation compared with KRAS‐mutant cases, with no significant difference shown between mutation sites. In two series of patients with lung adenocarcinoma, the PLA to detect EGFR‐GRB2 interaction was independently associated with longer survival (hazard ratio = 0.46, 95% confidence interval: 0.2–0.78, p = 0.0085 and hazard ratio = 0.48, 95% confidence interval: 0.2–0.85, p = 0.017). Total EGFR protein expression alone was not correlated with outcome. Conclusions EGFR colocalization with GRB2 as assessed by PLA is not correlated with EGFR expression levels or mutation status, defining a patient group that may show EGFR pathway activation, as illustrated by its prognostic value. Future studies may determine whether this group is more likely to respond to EGFR‐targeted therapies.

The Role of Biliary Drainage in Patients with Pancreatic Adenocarcinoma

Pancreatic cancer is one of the leading causes of cancer deaths worldwide and constitutes a major public health problem. One of the most common symptoms associated with pancreatic adenocarcinoma is jaundice, caused by the obstruction of common bile duct. Endobiliary stenting is used to relief these patients either preoperatively or merely for palliation and plastic or metal stents are usually endoscopically or percutaneously placed. Two interesting studies were presented at the 2014 ASCO Gastrointestinal Cancers Symposium. Strom et al. sought to investigate the effect of preoperative biliary drainage on recurrence and survival and they concluded that percutaneous biliary decompression was an independent predictor of worse overall survival and was associated with non-significant increase in hepatic recurrence (Abstract #314). Montero et al. presented the results of their study regarding the cost-effectiveness of metal stents in patients with inoperable pancreatic cancer and they concluded that placement of metal biliary stents is cost saving, improves overall survival and quality-adjusted survival compared with plastic stents (Abstract #260). Both studies concluded to useful results that along with the existing literature and formulated guidelines may help the provision of more effective, higher quality management of these patients.

Hypersensitivity reactions associated with oxaliplatin and their clinical management.

Introduction: Oxaliplatin, has become an integral part of the medical treatment of colorectal cancer and other malignancies. Increased use of the drug during the last decade, has led to increased occurrence of oxaliplatin-induced hypersensitivity reactions (HSRs), posing a significant challenge for clinicians. This article aims to review the existing literature regarding the incidence, clinical presentation, pathophysiology, risk factors and current management of oxaliplatin-induced HSRs. Areas covered: A systematic review of the English literature published in PubMed and Medline was undertaken. The clinical manifestations of HSRs were found to be variable and unpredictable. These reactions should be an important concern, as their potential life-threatening risks can force doctors to stop treatment and seek alternatives, which may be less effective, not as well tolerated and/or more expensive. There are a few strategies to prevent these reactions so that patients can still benefit from oxaliplatin. Such strategies include the use of premedication (steroid and antagonists of type I and II histamine receptors), prolonged infusion time and desensitization. Expert opinion: The presented management strategies as well as novel diagnostic tools including skin/intradermal tests and specific IgE have shown promising results. However, future research and validation are warranted in bigger clinical trials.

An assessment of neuronal calcium sensor-1 and response to neoadjuvant chemotherapy in breast cancer patients

Neuronal calcium sensor-1 (NCS-1) has been identified as a binding partner of the taxane, paclitaxel. Our previous study showed that overexpression of NCS-1 increased the efficacy of paclitaxel in vitro, but was associated with poor clinical outcome. Here, we determine if NCS-1 expression is associated with pathological complete response (pCR) to taxane-based neoadjuvant chemotherapy in 105 pre-treatment breast cancer biopsies. Elevated expression of NCS-1 was found to be positively associated with pCR. These results suggest that NCS-1 may be a predictive biomarker for response to taxane-based neoadjuvant chemotherapy in breast cancer.

Ki67 reproducibility using digital image analysis: an inter-platform and inter-operator study

Ki67 expression has been a valuable prognostic variable in breast cancer, but has not seen broad adoption due to lack of standardization between institutions. Automation could represent a solution. Here we investigate the reproducibility of Ki67 measurement between three image analysis platforms with supervised classifiers performed by the same operator, by multiple operators, and finally we compare their accuracy in prognostic potential. Two breast cancer patient cohorts were used for this study. The standardization was done with the 30 cases of ER+ breast cancer that were used in phase 3 of International Ki67 in Breast Cancer Working Group initiatives where blocks were centrally cut and stained for Ki67. The outcome cohort was from 149 breast cancer cases from the Yale Pathology archives. A tissue microarray was built from representative tissue blocks with median follow-up of 120 months. The Mib-1 antibody (Dako) was used to detect Ki67 (dilution 1:100). HALO (IndicaLab), QuantCenter (3DHistech), and QuPath (open source software) digital image analysis (DIA) platforms were used to evaluate Ki67 expression. Intraclass correlation coefficient (ICC) was used to measure reproducibility. Between-DIA platform reproducibility was excellent (ICC: 0.933, CI: 0.879–0.966). Excellent reproducibility was found between all DIA platforms and the reference standard Ki67 values of Spectrum Webscope (QuPath-Spectrum Webscope ICC: 0.970, CI: 0.936–0.986; HALO-Spectrum Webscope ICC: 0.968, CI: 0.933–0.985; QuantCenter-Spectrum Webscope ICC: 0.964, CI: 0.919–0.983). All platforms showed excellent intra-DIA reproducibility (QuPath ICC: 0.992, CI: 0.986–0.996; HALO ICC: 0.972, CI: 0.924–0.988; QuantCenter ICC: 0.978, CI: 0.932–0.991). Comparing each DIA against outcome, the hazard ratios were similar. The inter-operator reproducibility was particularly high (ICC: 0.962–0.995). Our results showed outstanding reproducibility both within and between-DIA platforms, including one freely available DIA platform (QuPath). We also found the platforms essentially indistinguishable with respect to prediction of breast cancer patient outcome. Results justify multi-institutional DIA studies to assess clinical utility.This study shows excellent reproducibility among 3 different digital image (DIA) analysis platforms in Ki67 scoring. An outstanding concordance was found among four operators using the same calibrated DIA platform suggesting a highly reproducible Ki67 scoring method. Finally, the authors also found that all three DIA platforms were essentially indistinguishable with respect to prediction of breast cancer patient outcome.