HER2 expression in oesophageal carcinoma and Barrett's oesophagus associated adenocarcinoma: An Australian study

C5b-9 Membrane Attack Complex Formation and Extracellular Vesicle Shedding in Barrett's Esophagus and Esophageal Adenocarcinoma

The early complement components have emerged as mediators of pro-oncogenic inflammation, classically inferred to cause terminal complement activation, but there are limited data on the activity of terminal complement in cancer. We previously reported elevated serum and tissue C9, the terminal complement component, in esophageal adenocarcinoma (EAC) compared to the precursor condition Barrett’s Esophagus (BE) and healthy controls. Here, we investigate the level and cellular fates of the terminal complement complex C5b-9, also known as the membrane attack complex. Punctate C5b-9 staining and diffuse C9 staining was detected in BE and EAC by multiplex immunohistofluorescence without corresponding increase of C9 mRNA transcript. Increased C9 and C5b-9 staining were observed in the sequence normal squamous epithelium, BE, low- and high-grade dysplasia, EAC. C5b-9 positive esophageal cells were morphologically intact, indicative of sublytic or complement-evasion mechanisms. To investigate this at a cellular level, we exposed non-dysplastic BE (BAR-T and CP-A), high-grade dysplastic BE (CP-B and CP-D) and EAC (FLO-1 and OE-33) cell lines to the same sublytic dose of immunopurified human C9 (3 µg/ml) in the presence of C9-depleted human serum. Cellular C5b-9 was visualized by immunofluorescence confocal microscopy. Shed C5b-9 in the form of extracellular vesicles (EV) was measured in collected conditioned medium using recently described microfluidic immunoassay with capture by a mixture of three tetraspanin antibodies (CD9/CD63/CD81) and detection by surface-enhanced Raman scattering (SERS) after EV labelling with C5b-9 or C9 antibody conjugated SERS nanotags. Following C9 exposure, all examined cell lines formed C5b-9, internalized C5b-9, and shed C5b-9⁺ and C9⁺ EVs, albeit at varying levels despite receiving the same C9 dose. In conclusion, these results confirm increased esophageal C5b-9 formation during EAC development and demonstrate capability and heterogeneity in C5b-9 formation and shedding in BE and EAC cell lines following sublytic C9 exposure. Future work may explore the molecular mechanisms and pathogenic implications of the shed C5b-9⁺ EV.

Clinical Relevance of Tissue and Serum Human Epidermal Growth Factor Receptor 2 Expression in Patients With Esophageal Squamous Cell Carcinoma

BACKGROUND

Serum and tissue human epidermal growth factor receptor 2 (HER2) levels were evaluated in resected esophageal squamous cell carcinoma (SCC) specimens to assess the relationship between HER2 expression and long-term prognosis.

METHODS

We included 95 patients who underwent esophagectomy for esophageal SCC. The serum HER2-extracellular domain (sHER2-ECD) levels were measured using an ELISA kit. A time-dependent receiver operating characteristics curve for censored survival outcomes was constructed to estimate the optimal cut-off value of sHER2-ECD (set at 4211 pg/mL). Immunohistochemical (IHC) staining was performed for HER2, and specimens were classified based on low (0 or 1+) or high HER2-IHC expression (2+ or 3+).

RESULTS

Patients with low sHER2-ECD levels showed poorly differentiated tumors, nodal involvement, and larger tumor size more frequently compared to patients with high sHER2-ECD levels. There were no differences in clinicopathological features based on HER2-IHC expression. Between patients with high and low HER2-IHC expression, the former group showed significantly higher sHER2-ECD levels. Patients with high sHER2-ECD levels had significantly favorable relapse-free survival (RFS) and overall survival (OS) compared to those with low sHER2-ECD levels. Conversely, patients with high HER2-IHC expression had significantly poorer RFS than did patients with low HER2-IHC expression, although no difference was observed in OS. Additionally, patients with high sHER2-ECD levels and low HER2-IHC expression had the highest OS and RFS among the patients studied.

CONCLUSIONS

The correlation among sHER2-ECD levels, HER2-IHC expression, and prognosis was demonstrated. Prospective studies are required to validate the impact of serum and tissue HER2 expression in esophageal SCC prognosis.

HER2-Directed Therapy in Advanced Gastric and Gastroesophageal Adenocarcinoma: Triumphs and Troubles

OPINION STATEMENT

Gastric and gastroesophageal junction (GEJ) cancers represent the third leading cause of malignancy-associated death worldwide. Approximately 15-20% of these adenocarcinomas overexpress the human epidermal growth factor receptor 2 (HER2), a pro-proliferative receptor tyrosine kinase that has been therapeutically exploited in other disease contexts. The landmark ToGA trial demonstrated that trastuzumab, an anti-HER2 antibody, could improve overall survival for patients with HER2 overexpressing advanced gastric and GEJ adenocarcinomas. In the ensuing decade, great effort has been made to refine and expand this therapeutic strategy through a variety of avenues including optimization of chemotherapy backbones, identifying potential synergy with immune checkpoint inhibition, deployment of alternative HER2-targeted antibodies, use of small molecule inhibitors, and development of HER2-directed antibody drug conjugates. While the results of these efforts have had variable success, they have led to a greater understanding of the mechanisms of both primary and acquired resistance to HER2-directed therapies, laying the groundwork for future investigations. Recently, KEYNOTE-811 and DESTINY-Gastric01 have led to the FDA approvals of pembrolizumab in combination with trastuzumab and chemotherapy in the 1st-line advanced setting and trastuzumab deruxtecan (fam-trastuzumab deruxtecan-nxki) in the 2nd-line setting, respectively. Herein, we review these significant works as well as discuss the ongoing investigations they have inspired, which aim to find and utilize additional means for targeting HER2 in gastric and GEJ cancers.

Prognostic features of the tumour microenvironment in oesophageal adenocarcinoma

Oesophageal adenocarcinoma (OAC) is a disease with an incredibly poor survival rate and a complex makeup. The growth and spread of OAC tumours are profoundly influenced by their surrounding microenvironment and the properties of the tumour itself. Constant crosstalk between the tumour and its microenvironment is key to the survival of the tumour and ultimately the death of the patient. The tumour microenvironment (TME) is composed of a complex milieu of cell types including cancer associated fibroblasts (CAFs) which make up the tumour stroma, endothelial cells which line blood and lymphatic vessels and infiltrating immune cell populations. These various cell types and the tumour constantly communicate through environmental cues including fluctuations in pH, hypoxia and the release of mitogens such as cytokines, chemokines and growth factors, many of which help promote malignant progression. Eventually clusters of tumour cells such as tumour buds break away and spread through the lymphatic system to nearby lymph nodes or enter the circulation forming secondary metastasis. Collectively, these factors need to be considered when assessing and treating patients clinically. This review aims to summarise the ways in which these various factors are currently assessed and how they relate to patient treatment and outcome at an individual level.

Prevalence of HER2 overexpression and amplification in squamous cell carcinoma of the esophagus: A systematic review and meta-analysis

Accurate data on HER2 positivity in esophageal squamous cell carcinoma patients (ESCC) is lacking. We conducted a systematic review and meta-analysis (Single Incidence Rates; metarate package, R) to examine the prevalence of HER2 in ESCC. Data on in situ hybridization (ISH) and immunohistochemistry (IHC) were extracted to derive pooled prevalence estimates, characteristics of the studies were extracted for subgroup analysis. Eighteen studies with 1505 patients were identified. HER2 gene amplification by ISH were prevalent in 10 % (95 % CI 6.9 %-15 %). Prevalence of HER2 overexpression (IHC3+) and borderline HER2 expression (IHC2+) were 6 % (95 % CI: 3.5 %-8.7 %) and 10 % (95 % CI: 6.0 %-17 %), respectively. An estimated 8.6 % (95 % CI: 5.5 %-13 %) of ESCC were HER2 positive using initial IHC followed by reflex ISH confirmation of borderline HER2 expression. In conclusion: Estimated prevalence of HER 2 positivity in ESCC were 10 % assessed by ISH and 8.6 % assessed by initial IHC followed by ISH.

GRB7 is an oncogenic driver and potential therapeutic target in oesophageal adenocarcinoma

Efficacious therapeutic approaches are urgently needed to improve outcomes in patients with oesophageal adenocarcinoma (OAC). However, oncogenic drivers amenable to targeted therapy are limited and their functional characterisation is essential. Among few targeted therapies available, anti‐human epidermal growth factor receptor 2 (HER2) therapy showed only modest benefit for patients with OAC. Herein, we investigated the potential oncogenic role of growth factor receptor bound protein 7 (GRB7), which is reported to be co‐amplified with HER2 (ERBB2) in OAC. GRB7 was highly expressed in 15% of OAC tumours, not all of which could be explained by co‐amplification with HER2, and was associated with a trend for poorer overall survival. Knockdown of GRB7 decreased proliferation and clonogenic survival, and induced apoptosis. Reverse phase protein array (RPPA) analyses revealed a role for PI3K, mammalian target of rapamycin (mTOR), MAPK, and receptor tyrosine kinase signalling in the oncogenic action of GRB7. Furthermore, the GRB7 and HER2 high‐expressing OAC cell line Eso26 showed reduced cell proliferation upon GRB7 knockdown but was insensitive to HER2 inhibition by trastuzumab. Consistent with this, GRB7 knockdown in vivo with an inducible shRNA significantly inhibited tumour growth in cell line xenografts. HER2 expression did not predict sensitivity to trastuzumab, with Eso26 xenografts remaining refractory to trastuzumab treatment. Taken together, our study provides strong evidence for an oncogenic role for GRB7 in OAC and suggests that targeting GRB7 may be a potential therapeutic strategy for this cancer. © 2020 The Authors. The Journal of Pathology published by John Wiley & Sons, Ltd. on behalf of The Pathological Society of Great Britain and Ireland.

Nephrotoxicity in cancer treatment: An overview

Anticancer drug nephrotoxicity is an important and increasing adverse drug event that limits the efficacy of cancer treatment. The kidney is an important elimination pathway for many antineoplastic drugs and their metabolites, which occurs by glomerular filtration and tubular secretion. Chemotherapeutic agents, both conventional cytotoxic agents and molecularly targeted agents, can affect any segment of the nephron including its microvasculature, leading to many clinical manifestations such as proteinuria, hypertension, electrolyte disturbances, glomerulopathy, acute and chronic interstitial nephritis, acute kidney injury and at times chronic kidney disease. The clinician should be alert to recognize several factors that may maximize renal dysfunction and contribute to the increased incidence of nephrotoxicity associated with these drugs, such as intravascular volume depletion, the associated use of nonchemotherapeutic nephrotoxic drugs (analgesics, antibiotics, proton pump inhibitors, and bone-targeted therapies), radiographic ionic contrast media or radiation therapy, urinary tract obstruction, and intrinsic renal disease. Identification of patients at higher risk for nephrotoxicity may allow the prevention or at least reduction in the development and severity of this adverse effect. Therefore, the aim of this brief review is to provide currently available evidences on oncologic drug-related nephrotoxicity.

Prognostic and therapeutic molecular markers in the clinical management of esophageal cancer

Introduction: Esophageal cancer is a deadly disease with high mortality. Treatment with chemotherapy, radiation, and surgery continues to leave many patients with disease progression and recurrence. Novel treatments are needed for this patient population. The development of molecular markers are important for identifying therapeutic targets, as well as prognosis.Areas covered: This review evaluates three molecular markers in esophageal cancer: HER2, PD-L1, and MSI. The fundamentals of these markers, diagnosis, and rates of occurrence in esophageal cancer are explored. The prognostic potential of these markers is based on existing literature as well as application in clinical trials. Key trial findings pertaining to the therapeutic targets for HER2 and PD-1 as well as the role of MSI are discussed.Expert commentary: Molecular markers are changing the practice for esophageal cancer. Therapeutic targeting for HER2 and PD-L1 have shown positive results in recent clinical trials. Trials evaluating immunotherapy as first-line agents are currently underway.

Current Development of Monoclonal Antibodies in Cancer Therapy

Exploiting the unique specificity of monoclonal antibodies has revolutionized the treatment and diagnosis of haematological and solid organ malignancies; bringing benefit to millions of patients over the past decades. Recent achievements include conjugating antibodies with toxic payloads resulting in superior efficacy and/or reduced toxicity, development of molecular imaging techniques targeting specific antigens for use as predictive and prognostic biomarkers, the development of novel bi- and tri-specific antibodies to enhance therapeutic benefit and abrogate resistance and the success of immunotherapy agents. In this chapter, we review an overview of antibody structure and function relevant to cancer therapy and provide an overview of pivotal clinical trials which have led to regulatory approval of monoclonal antibodies in cancer treatment. We further discuss resistance mechanisms and the unique side effects of each class of antibody and provide an overview of emerging therapeutic agents.

A systematic review and meta-analysis of prognostic biomarkers in resectable esophageal adenocarcinomas

Targeted therapy is lagging behind in esophageal adenocarcinoma (EAC). To guide the development of new treatment strategies, we provide an overview of the prognostic biomarkers in resectable EAC treated with curative intent. The Medline, Cochrane and EMBASE databases were systematically searched, focusing on overall survival (OS). The quality of the studies was assessed using a scoring system ranging from 0-7 points based on modified REMARK criteria. To evaluate all identified prognostic biomarkers, the hallmarks of cancer were adapted to fit all biomarkers based on their biological function in EAC, resulting in the features angiogenesis, cell adhesion and extra-cellular matrix remodeling, cell cycle, immune, invasion and metastasis, proliferation, and self-renewal. Pooled hazard ratios (HR) and 95% confidence intervals (CI) were derived by random effects meta-analyses performed on each hallmarks of cancer feature. Of the 3298 unique articles identified, 84 were included, with a mean quality of 5.9 points (range 3.5-7). The hallmarks of cancer feature 'immune' was most significantly associated with worse OS (HR 1.88, (95%CI 1.20-2.93)). Of the 82 unique prognostic biomarkers identified, meta-analyses showed prominent biomarkers, including COX-2, PAK-1, p14ARF, PD-L1, MET, LC3B, IGFBP7 and LGR5, associated to each hallmark of cancer.

Hyperinsulinemia Promotes Esophageal Cancer Development in a Surgically-Induced Duodeno-Esophageal Reflux Murine Model

Hyperinsulinemia could have a role in the growing incidence of esophageal adenocarcinoma (EAC) and its pre-cancerous lesion, Barrett's Esophagus, a possible consequence of Gastro-Esophageal Reflux Disease. Obesity is known to mediate esophageal carcinogenesis through different mechanisms including insulin-resistance leading to hyperinsulinemia, which may mediate cancer progression via the insulin/insulin-like growth factor axis. We used the hyperinsulinemic non-obese FVB/N (Friend leukemia virus B strain) MKR (muscle (M)-IGF1R-lysine (K)-arginine (R) mouse model to evaluate the exclusive role of hyperinsulinemia in the pathogenesis of EAC related to duodeno-esophageal reflux. FVB/N wild-type (WT) and MKR mice underwent jejunum-esophageal anastomosis side-to end with the exclusion of the stomach. Thirty weeks after surgery, the esophagus was processed for histological, immunological and insulin/Insulin-like growth factor 1 (IGF1) signal transduction analyses. Most of the WT mice (63.1%) developed dysplasia, whereas most of the MKR mice (74.3%) developed squamous cell and adenosquamous carcinomas, both expressing Human Epidermal growth factor receptor 2 (HER2). Hyperinsulinemia significantly increased esophageal cancer incidence in the presence of duodenal-reflux. Insulin receptor (IR) and IGF1 receptor (IGF1R) were overexpressed in the hyperinsulinemic condition. IGF1R, through ERK1/2 mitogenic pattern activation, seems to be involved in cancer onset. Hyperinsulinemia-induced IGF1R and HER2 up-regulation could also increase the possibility of forming of IGF1R/HER2 heterodimers to support cell growth/proliferation/progression in esophageal carcinogenesis.

Evolution of anti-HER2 therapies for cancer treatment

The development of HER2-directed monoclonal antibodies and tyrosine kinase inhibitors have provided benefits to cancer patients, as well as produced many insights into the biology of the ErbB receptor family. Current therapies based on ErbB family members have resulted in improved overall survival with associated improvements in quality of life for the cancer patients that respond to treatment. Compared to monotherapy using either two antibodies to block the HER2 receptor blockade or combinatorial approaches with HER2 antibodies and standard therapies has provided additional benefits. Despite the therapeutic success of existing HER2 therapies, personalising treatment and overcoming resistance to these therapies remains a significant challenge. The heterogeneous intra-tumoural HER2 expression and lack of fully predictive and prognostic biomarkers remain significant barriers to improving the use of HER2 antibodies. Imaging modalities using radiolabelled pertuzumab and trastuzumab allow quantitative assessment of intra-tumoural HER2 expression, HER2 antibody saturation and the success of different drug delivery systems to be assessed. Molecular imaging with HER2 antibodies has the potential to be a non-invasive, predictive and prognostic technique capable of influencing therapeutic decisions, predicting response and failure of treatments as well as providing insights into receptor recycling and signalling. Similarly, conjugating HER2 antibodies with novel toxic payloads or combining HER2 antibodies with cellular immunotherapy provide exciting new opportunities for the management of tumours overexpressing HER2. Future research will lead to higher therapeutic responses, lower toxicities and providing insight into the mechanisms of resistance to HER2-targeted treatments.