Targeting the HER2 pathway for the therapy of lower esophageal and gastric adenocarcinoma

Disitamab vedotin: a novel antibody-drug conjugates for cancer therapy

Human epidermal growth factor receptor 2 (HER2) regulates cell mitosis, proliferation, and apoptosis. Trastuzumab is a HER2-targeted monoclonal antibody (mAB), which can prolong the overall survival rate of patients with HER2 overexpression in later periods of gastric cancer and breast cancer. Although anti-HER2 monoclonal antibody has a curative effect, adjuvant chemotherapy is still necessary to upgrade the curative effect maximumly. Antibody-drug conjugate (ADC) is a kind of therapeutic drug that contains antigen-specific antibody and cytotoxic payload, which can improve the survival time of tumor patients. To date, there are several HER2-ADC products on the market, for which two anti-HER2 ADC (trastuzumab emtansine and trastuzumab deruxtecan) have been authorized by the FDA for distinct types of HER2-positive carcinoma in the breast. Disitamab vedotin (RC48) is a newly developed ADC drug targeting HER2 that is comprised of hertuzumab coupling monomethyl auristatin E (MMAE) via a cleavable linker. This paper aims to offer a general insight and summary of the mechanism of action and the currently completed and ongoing clinical studies of RC-48 in HER-2 positive solid tumors.

Prevalence of HER2 Expression and Its Correlation with Clinicopathological Parameters in Gastric or Gastroesophageal Junction Adenocarcinoma in North-East Indian Population

Objective: Human epidermal growth factor receptor 2 (erbb2/HER2) overexpression, has now been implicated in advanced gastric and gastroesophageal junction cancers. The study was conducted to determine the rate of HER2 positivity in patients with locally advanced or metastatic gastric and gastroesophageal adenocarcinoma in North-East India and to assess the impact of various demographic and clinical parameters on HER2 positivity. Methods: A total of 68 patients of age >18 years of gastric and gastroesophageal adenocarcinoma diagnosed on histopathological examination from September 2016 to February 2018 at Dr B Borooah Cancer Institute, Assam were enrolled for the observational (epidemiological) study. All patients were subjected to the HER2 immunohistochemistry test using a FDA-approved, standardized test kit. HER2 expression was correlated with various demographic and clinicopathological parameters. Results: The overall rate of HER2 positivity in the population studied was 56% (n=38). The rate was non-significantly higher in male, older age group (>60 years) and Hindu population. Similarly, HER2 positivity rate was higher in patients with well differentiated histology and was more common in patients with stage II and III diseases, but neither of the associations is statistically significant. HER2 positivity rate was significantly higher in proximal and in GEJ tumours (56% versus 44%, P=0.002). Conclusion: HER2 overexpression was evident in 56% of the North-East Indian patients with locally advanced and metastatic gastric and gastroesophageal adenocarcinoma. The overexpression correlated significantly with primary tumour site. Routine testing of gastric and gastroesophageal tumours for HER2 expression is recommended to provide a therapeutic advantage in Indian patients.

Expression and prognostic value of HER-2/neu in primary breast cancer with sentinel lymph node metastasis

The present study explores the correlation of human epidermal growth factor receptor-2 (HER-2) protein expression with sentinel lymph node (SLN) metastasis and prognosis of breast cancer. The breast cancer tissues and adjacent tissues were obtained from patients with primary breast cancer. Quantitative real-time polymerase chain reaction (qRT-PCR) was performed to detect the mRNA level of HER-2. Spearman correlation analysis was used to analyze the correlation of HER-2 expression with SLN metastasis. The disease-free survival (DFS) and overall survival (OS) of breast cancer patients were investigated. Univariate and multivariate analyses were performed to explore factors influencing SLN metastasis and prognosis of breast cancer. Compared with adjacent tissues, HER-2 expression was significantly up-regulated in breast cancer tissues. HER-2 expression was correlated with the pathological type, tumor node metastasis (TNM) staging, histological grade, blood vessel invasion, SLN metastasis, estrogen receptor (ER), and progesterone receptor (PR). The expression level of HER-2 was positively related to the SLN metastasis (r=0.548). Median DFS and OS were longer in patients with negative HER-2 expression than in patients with positive HER-2 expression. TNM staging, SLN metastasis, and expression levels of HER-2 and ER were independent factors for DFS of breast cancer patients, while TNM staging, blood vessel invasion, histological grade, SLN metastasis, and expression levels of HER-2 and PR were independent factors for OS of breast cancer patients. Our study suggests that high expression of HER-2 promoted SLN metastasis. HER-2 expression and SLN metastasis were the independent factors for the prognosis of breast cancer.

Impact of HER2 expression on outcome in gastric cancer patients with liver metastasis

PURPOSE

We aim to investigate the correlation of HER2 expression with liver metastasis and the impact of HER2 status and trastuzumab therapy on the prognosis of gastric cancer with liver metastasis (GCLM) patients.

METHODS

This prospective observational study was carried out in Shanghai Zhongshan Hospital, Fudan University, from January 2012 to June 2015. HER2 status and baseline characteristics were collected from the patient record. GCLM patients were divided into three groups according to HER2 status and trastuzumab therapy.

RESULTS

A total of 290 patients were included, and94 patients were diagnosed with liver metastasis. The HER2 positivity was 37.2 % (35/94) in GCLM patients and 21 % (61/290) in the overall GC patients. Among 94 GCLM patients, 28 HER2-positive patients received trastuzumab-based therapy (group A), 7 HER2-positive patients received chemotherapy alone (group B) and the other 59 patients were HER2 negative (group C). The median progression-free survival (PFS) for groups A, B and C was 7.83, 6.30 and 5.33 months, respectively (P = 0.007). The median overall survival (OS) for groups A, B and C was 12.00, 10.47 and 8.67 months, respectively (P = 0.056). Further Cox analysis showed that there was no significant difference in OS (P = 0.917) and PFS (P = 0.456) between group B and C.

CONCLUSIONS

HER2 positivity was higher in GCLM patients. HER2 status itself was not an independent prognostic factor in GCLM patients. Trastuzumab-based therapy could significantly improve survival in HER2-positive GCLM patients.

Evaluation of Trastuzumab Anti-Tumor Efficacy and its Correlation with HER-2 Status in Patient-Derived Gastric Adenocarcinoma Xenograft Models

The aim of the study was to investigate trastuzumab anti-tumor efficacy and its correlation with HER-2 status in primary xenograft models derived from Chinese patients with gastric adenocarcinoma. Patient-derived gastric adenocarcinoma xenograft (PDGAX) mouse models were firstly generated by implanting gastric adenocarcinoma tissues from patients into immune deficient mice. A high degree of histological and molecular similarity between the PDGAX mouse models and their corresponding patients’ gastric adenocarcinoma tissues was shown by pathological observation, HER-2 expression, HER-2 gene copy number, and mutation detection. Based on Hoffmann’s criteria in gastric cancer, three models (PDGAX001, PDGAX003 and PDGAX005) were defined as HER-2 positive with fluorescence in situ hybridization (FISH) amplification or immunohistochemistry (IHC) 2+/ 3+, while two models (PDGAX002, PDGAX004) were defined as HER-2 negative. Upon trastuzumab treatment, significant tumor regression (105 % TGI) was observed in model PDGAX005 (TP53 wt), while moderate sensitivity (26 % TGI) was observed in PDGAX003, and resistance was observed in PDGAX001, 002 and 004. A significant increase in HER-2 gene copy number was only observed in PDGAX005 (TP53 wt). Interestingly, trastuzumab showed no efficacy in PDGAX001 (HER2 IHC 3+ and FISH amplification, but with mutant TP53). Consistent with this finding, phosphor-HER2 modulation by trastuzumab was observed in model PDGAX005, but not in PDGAX001.

Genetics of gastric cancer

Gastric cancer remains highly prevalent and accounts for a notable proportion of global cancer mortality. This cancer is also associated with poor survival rates. Understanding the genetic basis of gastric cancer will offer insights into its pathogenesis, help identify new biomarkers and novel treatment targets, aid prognostication and could be central to developing individualized treatment strategies in the future. An inherited component contributes to <3% of gastric cancers; the majority of genetic changes associated with gastric cancer are acquired. Over the past few decades, advances in technology and high-throughput analysis have improved understanding of the molecular aspects of the pathogenesis of gastric cancer. These aspects are multifaceted and heterogeneous and represent a wide spectrum of several key genetic influences, such as chromosomal instability, microsatellite instability, changes in microRNA profile, somatic gene mutations or functional single nucleotide polymorphisms. These genetic aspects of the pathogenesis of gastric cancer will be addressed in this Review.

Gallium-68: chemistry and radiolabeled peptides exploring different oncogenic pathways

Abstract Early and specific tumor detection and also therapy selection and response evaluation are some challenges of personalized medicine. This calls for high sensitive and specific molecular imaging such as positron emission tomography (PET). The use of peptides for PET molecular imaging has undeniable advantages: possibility of targeting through peptide-receptor interaction, small size and low-molecular weight conferring good penetration in the tissue or at cellular level, low toxicity, no antigenicity, and possibility of wide choice for radiolabeling. Among β(+)-emitter radioelements, Gallium-68 is a very attractive positron-emitter compared with carbon-11 or fluorine-18 taking into account its easy production via a (68)Ge/(68)Ga generator and well established radiochemistry. Gallium-68 chemistry is based on well-defined coordination complexes with macrocycle or chelates having strong binding properties, particularly suitable for linking peptides that allow resistance to in vivo transchelation of the metal ion. Understanding specific and nonspecific molecular mechanisms involved in oncogenesis is one major key to develop new molecular imaging tools. The present review focuses on peptide signaling involved in different oncogenic pathways. This peptide signalization might be common for tumoral and non-tumoral processes or could be specific of an oncological process. This review describes gallium chemistry and different (68)Ga-radiolabeled peptides already in use or under development aiming at developing molecular PET imaging of different oncological processes.

Correlation of human epidermal growth factor receptor 2 expression with clinicopathological characteristics and prognosis in gastric cancer

AIM: To investigate human epidermal growth factor receptor 2 (HER2) gene amplification and protein expression in Chinese patients with resectable gastric cancer and the association with clinicopathological characteristics and survival.

METHODS: One hundred and ninety-seven gastric cancer patients who underwent curative surgery procedures were enrolled into this study. HER2 gene amplification and protein expression were examined using fluorescence in-situ hybridization (FISH) and immunohistochemistry (IHC) analysis on formalin-fixed paraffin-embedded gastric cancer samples from all patients. For scoring, Hofmann’s HER2 gastric cancer scoring system was adopted. All cases showing IHC3+ or FISH positivity were defined as HER2 positive. Patient clinicopathological data and survival information were collected. Finally, χ² statistical analysis was performed to analyze the HER2 positivity rate amongst the subgroups with different clinicopathological characteristics including; gender, age, tumor location, Lauren classification, differentiation, TNM staging, depth of invasion, lymph node metastases and distant metastasis. The probability of survival for different subgroups with different clinicopathological characteristics was calculated using the Kaplan-Meier method and survival curves plotted using log rank inspection.

RESULTS: According to Hofmann’s HER2 gastric cancer scoring criteria, 31 cases (15.74%) were identified as HER2 gene amplified and 19 cases (9.64%) were scored as strongly positive for HER2 membrane staining (3+), 25 cases (12.69%) were moderately positive (2+) and 153 cases (77.66%) were HER2 negative (0/1+). The concordance rate between IHC and FISH analyses was 88.83% (175/197). Thirty-six cases were defined as positive for HER2 gene amplification and/or protein expression, with 24 of these cases being eligible for Herceptin treatment according to United States recommendations, and 29 of these cases eligible according to EU recommendations. Highly consistent results were detected between IHC3+, IHC0/1 and FISH (73.68% and 95.42%), but low consistency was observed between IHC2+ and FISH (40.00%). The positivity rates in intestinal type and well-differentiated gastric cancer were higher than those in diffuse/mixed type and poorly-differentiated gastric cancer respectively (28.57% vs 13.43%, P = 0.0103; 37.25% vs 11.64%, P < 0.0001), but were not correlated with gender, age, tumor location or TNM stage, depth of invasion, lymph node metastases and distant metastasis. In poorly-differentiated gastric cancer patients, those without lymph node metastasis showed a higher HER2 positivity rate than those with lymph node metastasis (26.47% vs 7.14%, P = 0.0021). This association was not present in those patients with well-differentiated gastric cancer (28.57% vs 43.33%, P = 0.2832). Within our patient cohort, 26 cases were lost to follow-up. The median survival time for the remaining 171 patients was 18 mo. The median survival times of the HER2 positive and negative groups were 17 and 18.5 mo respectively. Overall survival was not significantly different between HER2-positive and negative groups (χ² = 0.9157, P = 0.3386), but in patients presenting well-differentiated tumors, the overall survival of the HER2-positive group was significantly worse than that of the HER2-negative group (P = 0.0123). In contrast, patients with poorly differentiated and diffuse/mixed subtype gastric cancers showed no significant differences in overall survival associated with HER2. Furthermore, the median survival time of the HER2 positive group did not show any statistically significant differences when compared to the subgroups of gender, age, tumor location, TNM classification, lymph node metastases and distant metastasis.

CONCLUSION: Patients with intestinal type gastric cancer (GC), well-differentiated GC and poorly-differentiated GC without lymph node metastasis, may all represent suitable candidates for targeted therapy using Herceptin.

Whole exome sequencing of pediatric gastric adenocarcinoma reveals an atypical presentation of Li-Fraumeni syndrome

BACKGROUND

Gastric adenocarcinoma is a rare diagnosis in childhood. A 14-year-old male patient presented with metastatic gastric adenocarcinoma, and a strong family history of colon cancer. Clinical sequencing of CDH1 and APC were negative. Whole exome sequencing was therefore applied to capture the majority of protein-coding regions for the identification of single-nucleotide variants, small insertion/deletions, and copy number abnormalities in the patient's germline as well as primary tumor.

MATERIALS AND METHODS

DNA was extracted from the patient's blood, primary tumor, and the unaffected mother's blood. DNA libraries were constructed and sequenced on Illumina HiSeq2000. Data were post-processed using Picard and Samtools, then analyzed with the Genome Analysis Toolkit. Variants were annotated using an in-house Ensembl-based program. Copy number was assessed using ExomeCNV.

RESULTS

Each sample was sequenced to a mean depth of coverage of greater than 120×. A rare non-synonymous coding single-nucleotide variant (SNV) in TP53 was identified in the germline. There were 10 somatic cancer protein-damaging variants that were not observed in the unaffected mother genome. ExomeCNV comparing tumor to the patient's germline, identified abnormal copy number, spanning 6,946 genes.

CONCLUSION

We present an unusual case of Li-Fraumeni detected by whole exome sequencing. There were also likely driver somatic mutations in the gastric adenocarcinoma. These results highlight the need for more thorough and broad scale germline and cancer analyses to accurately inform patients of inherited risk to cancer and to identify somatic mutations.

The new era of staging as a key for an appropriate treatment for esophageal cancer

Fluorodeoxyglucose-positron emission tomography (FDG-PET) and computed tomography (CT) have become the gold standard for staging of esophageal cancer by detecting distant metastases, but metastatic lymph nodes are often difficult to diagnose from the size and standardized uptake value (SUV). If we compare the diagnostic performance of endoscopic ultrasonography (EUS), CT, and FDG-PET in staging of esophageal cancer, EUS is the most sensitive method to identify the detection of regional lymph node metastases, whereas CT and FDG-PET are more specific tests. Combination study with CT, EUS and PETCT cannot make a precise diagnosis after neoadjuvant therapy (NAT). A precise staging might be determined by the fine needle aspiration biopsy (FNAB) under EUS and US screening in the neck and the abdomen even after NAT. Indication of endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) for superficial cancer is sensitive because of difficulty in T1b cancer diagnosis. Detailed examination about vessel invasion and the possibility of residual tumor with dissected specimen will offer an appropriate additional therapy. New strategy like sentinel lymph node (SLN) navigation could supply more information about lymphatic routes and metastatic nodes. SLN navigation with ESD might become a new less invasive strategy for superficial esophageal cancer.

Metastatic gastric cancer treatment: a little slow but worthy progress

Metastatic gastric cancer is incurable and remains one of the leading causes of cancer-related deaths around the world. Despite the significant progress in its systemic treatment, metastatic gastric cancer is still a major therapeutic challenge for oncologists. Newer chemotherapy regimens and the addition of molecularly targeted agents to chemotherapy seem to provide better clinical outcomes for patients with metastatic gastric cancer. The objective of this article is to review the current treatment approach for this formidable disease.

Predicting the response to chemotherapy in gastric adenocarcinoma: who benefits from neoadjuvant chemotherapy?

Despite a decline in the overall incidence, gastric adenocarcinoma remains the second most common cause of cancer death worldwide and thus a significant global health problem. Even in early-stage locoregional confined disease the 5-year survival rarely exceeds 25-35 %. Randomized trials have demonstrated a benefit from neoadjuvant and perioperative chemotherapy. However the optimal approach in individual patients is not clear and remains controversial. A consistent finding is that patients who have a histopathological response to neoadjuvant therapy are more likely to receive a survival benefit. These clinical data provide a strong argument for the urgent development of methods to predict histopathological response to neoadjuvant therapies for gastric adenocarcinomas. Published data demonstrate that clinico-pathological features (tumour histology and location), imaging through metabolic response by FDG-PET and tissue/molecular biomarkers may all have a predictive value for neoadjuvant therapies. However it is still uncertain from published data whether or not they will be useful for clinical decision making in individual patients. Existing candidate biomarkers need to be properly qualified and validated and novel biomarkers are required and an optimal approach should involve the combination and integration of clinical, imaging, pathological and molecular biomarkers.