Clinical significance of intratumoral HER2 heterogeneity on trastuzumab efficacy using endoscopic biopsy specimens in patients with advanced HER2 positive gastric cancer

Exploratory analysis of serum HER2 extracellular domain for HER2 positive gastric cancer treated with SOX plus trastuzumab

BACKGROUND

The aim of this study was to explore the clinical utility of serum HER2 extracellular domain (sHER2 ECD) using data from a clinical trial evaluating trastuzumab combined S-1 plus oxaliplatin (SOX) in HER2 positive gastric cancer.

METHODS

sHER2 ECD were prospectively measured at baseline and subsequent treatment courses. Based on each quantile point of baseline sHER2 ECD levels and its early changes, patients were divided into two groups and compared clinical outcomes.

RESULTS

43 patients were enrolled, and 17 patients (39.5%) were positive for baseline sHER2 ECD. Higher baseline sHER2 ECD levels tended to have lower hazard ratios (HRs). When divided into two groups by baseline sHER2 ECD of 19.1 ng/ml, median progression-free survival (PFS) and overall survival (OS) was longer in the higher group (mPFS: 16.8 vs 8.7 months, p = 0.359. mOS: 35.5 vs 20.6 months, p = 0.270), respectively. After initiation of treatment, sHER2 ECD significantly decreased up until the third cycle. Higher reduction rates of sHER2 ECD within 3 cycles also tended to have lower HRs. When divided into two groups by reduction rate of 42.5%, mPFS and mOS was longer in the higher reduced group (mPFS: 17.2 vs 8.7 months, p = 0.095. mOS: 65.0 vs 17.8 months, p = 0.047), respectively. Furthermore, higher reduction rates could surrogate higher objective response rates (ORR) (ORR: 90% vs 63.2% for 29.5%, p = 0.065. 100% vs 70% for 42.5%, p = 0.085), respectively.

CONCLUSIONS

Baseline sHER2 ECD levels and its early decline may be useful biomarkers for SOX plus trastuzumab efficacy in HER2 positive gastric cancer.

Molecular classification and intratumoral heterogeneity of gastric adenocarcinoma

Gastric cancers frequently harbor striking histological complexity and diversity between lesions as well as within single lesions, known as inter- and intratumoral heterogeneity, respectively. The latest World Health Organization Classification of Tumors designated more than 30 histological subtypes for gastric epithelial tumors, assigning 12 subtypes for gastric adenocarcinoma (GAD). Meanwhile, recent advances in genome-wide analyses have provided molecular aspects to the histological classification of GAD, and consequently revealed different molecular traits underlying these histological subtypes. Moreover, accumulating knowledge of comprehensive molecular profiles has led to establishing molecular classifications of GAD, which are often associated with clinical biomarkers for therapeutics and prognosis. However, most of our knowledge of GAD molecular profiles is based on inter-tumoral heterogeneity, and the molecular profiles underlying intratumoral heterogeneity are yet to be determined. In this review, recently established molecular classifications of GAD are introduced in the aspect of pathological diagnosis and are discussed in the context of intratumoral heterogeneity.

Metabolic heterogeneity affects trastuzumab response and survival in HER2-positive advanced gastric cancer

BACKGROUND

Trastuzumab is the only first-line treatment targeted against the human epidermal growth factor receptor 2 (HER2) approved for patients with HER2-positive advanced gastric cancer. The impact of metabolic heterogeneity on trastuzumab treatment efficacy remains unclear.

METHODS

Spatial metabolomics via high mass resolution imaging mass spectrometry was performed in pretherapeutic biopsies of patients with HER2-positive advanced gastric cancer in a prospective multicentre observational study. The mass spectra, representing the metabolic heterogeneity within tumour areas, were grouped by K-means clustering algorithm. Simpson's diversity index was applied to compare the metabolic heterogeneity level of individual patients.

RESULTS

Clustering analysis revealed metabolic heterogeneity in HER2-positive gastric cancer patients and uncovered nine tumour subpopulations. High metabolic heterogeneity was shown as a factor indicating sensitivity to trastuzumab (p = 0.008) and favourable prognosis at trend level. Two of the nine tumour subpopulations associated with favourable prognosis and trastuzumab sensitivity, and one subpopulation associated with poor prognosis and trastuzumab resistance.

CONCLUSIONS

This work revealed that tumour metabolic heterogeneity associated with prognosis and trastuzumab response based on tissue metabolomics of HER2-positive gastric cancer. Tumour metabolic subpopulations may provide an association with trastuzumab therapy efficacy.

CLINICAL TRIAL REGISTRATION

The patient cohort was conducted from a multicentre observational study (VARIANZ;NCT02305043).

Targeting HER2 in Gastroesophageal Adenocarcinoma: Molecular Features and Updates in Clinical Practice

Gastroesophageal adenocarcinoma (GEA) is one of the principal causes of death related to cancer globally. Human epidermal growth factor receptor 2 (HER2) is a tyrosine kinase receptor which is found to be overexpressed or amplified in approximately 20% of GEA cases. In GEA, the identification of HER2-positive status is crucial to activate a specific anti-HER2 targeted therapy. The landmark ToGA trial demonstrated the superiority of adding trastuzumab to platinum-based chemotherapy, becoming the first-line standard of treatment. However, unlike breast cancer, the efficacy of other anti-HER2 drugs, such as lapatinib, pertuzumab, and T-DM1, has failed to improve outcomes in advanced and locally advanced resectable GEA. Recently, the combination of trastuzumab with pembrolizumab, along with chemotherapy, and the development of trastuzumab deruxtecan, with its specific bystander activity, demonstrated improved outcomes, renewing attention in the treatment of this disease. This review will summarise historical and emerging therapies for the treatment of HER2-positive GEA, with a section dedicated to the HER2 molecular pathway and the use of novel blood biomarkers, such as circulating tumour DNA and circulating tumour cells, which may be helpful in the future to guide treatment decisions.

Deep learning model based on multi-lesion and time series CT images for predicting the benefits from anti-HER2 targeted therapy in stage IV gastric cancer

OBJECTIVE

To develop and validate a deep learning model based on multi-lesion and time series CT images in predicting overall survival (OS) in patients with stage IV gastric cancer (GC) receiving anti-HER2 targeted therapy.

METHODS

A total of 207 patients were enrolled in this multicenter study, with 137 patients for retrospective training and internal validation, 33 patients for prospective validation, and 37 patients for external validation. All patients received anti-HER2 targeted therapy and underwent pre- and post-treatment CT scans (baseline and at least one follow-up). The proposed deep learning model evaluated the multiple lesions in time series CT images to predict risk probabilities. We further evaluated and validated the risk score of the nomogram combining a two-follow-up lesion-based deep learning model (LDLM-2F), tumor markers, and clinical information for predicting the benefits from treatment (Nomo-LDLM-2F).

RESULTS

In the internal validation and prospective cohorts, the one-year AUCs for Nomo-LDLM-2F using the time series medical images and tumor markers were 0.894 (0.728-1.000) and 0.809 (0.561-1.000), respectively. In the external validation cohort, the one-year AUC of Nomo-LDLM-2F without tumor markers was 0.771 (0.510-1.000). Patients with a low Nomo-LDLM-2F score derived survival benefits from anti-HER2 targeted therapy significantly compared to those with a high Nomo-LDLM-2F score (all p < 0.05).

CONCLUSION

The Nomo-LDLM-2F score derived from multi-lesion and time series CT images holds promise for the effective readout of OS probability in patients with HER2-positive stage IV GC receiving anti-HER2 therapy.

CRITICAL RELEVANCE STATEMENT

The deep learning model using baseline and early follow-up CT images aims to predict OS in patients with stage IV gastric cancer receiving anti-HER2 targeted therapy. This model highlights the spatiotemporal heterogeneity of stage IV GC, assisting clinicians in the early evaluation of the efficacy of anti-HER2 therapy.

KEY POINTS

• Multi-lesion and time series model revealed the spatiotemporal heterogeneity in anti-HER2 therapy. • The Nomo-LDLM-2F score was a valuable prognostic marker for anti-HER2 therapy. • CT-based deep learning model incorporating time-series tumor markers improved performance.

Targeting HER2 heterogeneity in breast and gastrointestinal cancers

About 20% of breast and gastric cancers and 3% of colorectal carcinomas overexpress the human epidermal growth factor receptor 2 (HER2) and are sensitive to HER2-directed agents. The expression of HER2 may differ within the same tumoral lesion (spatial intralesional heterogeneity), from different tumor locations (spatial interlesional heterogeneity), and throughout treatments (temporal heterogeneity). Spatial and temporal heterogeneity may impact on response and resistance to HER2-targeting agents and its prevalence and predictive role changes across HER2-overexpressing solid tumors. Therefore, the definition and the characterization of HER2 heterogeneity pose many challenges and its implementation as a reproducible predictive biomarker would help in guiding treatment modulation.

GASTric Cancer HER2 Re-Assessment Study 2 (GASTHER2): HER2 Re-assessment for Initially HER2-Negative Advanced Gastric Cancer Patients after Progression on First-Line Treatment

PURPOSE

Heterogeneous human epidermal growth factor receptor 2 (HER2) overexpression in gastric cancer may lead to a misdiagnosis of HER2 status. Accurate assessment of HER2 status is essential for optimal treatment as novel HER2-directed agents are being investigated in various clinical settings. We evaluated the usefulness of HER2 re-assessment following progression on first-line treatment in initially HER2-negative advanced gastric cancer (AGC) patients.

MATERIALS AND METHODS

We enrolled 177 patients with baseline HER2-negative AGC and performed HER2 re-assessment after progression on first-line treatment from February 2012 to June 2016 at Asan Medical Center, Seoul, Korea. The re-assessed HER2 status was analyzed with baseline HER2 status and clinical characteristics.

RESULTS

The median age was 54 years (range, 24 to 80 years), and 123 patients (69.5%) were men. Seven patients (4.0%) were HER2-positive on the re-assessment. Patients with baseline HER2 negativity confirmed by a single test (n=100) had a higher HER2-positive re-assessment rate compared to those who had repeated baseline testing (n=77) (5.0% vs. 2.6%). Among the patients with single baseline HER2 testing, the rate was higher in patients with baseline HER2 immunohistochemistry (IHC) 1+ compared to those with IHC 0 (13.4% vs. 3.6%).

CONCLUSION

Overall, 4.0% of patients with baseline HER2-negative AGC were HER2-positive on re-assessment, and the HER2-positive re-assessment rate was higher among patients who had a single test at baseline. HER2 re assessment may be considered for initially HER2-negative patients to determine their eligibility for HER2-directed therapy, particularly if their HER2 negativity was determined by a single test, especially if they had a single baseline HER2 IHC 1+ test.

Down-regulation of stimulator of interferon genes (STING) expression and CD8+ T-cell infiltration depending on HER2 heterogeneity in HER2-positive gastric cancer

BACKGROUND

HER2 signaling might be involved in the regulation of immune cell activation in the tumor microenvironment (TME) of gastric cancer (GC). However, the relationship between HER2 status and immune cell condition in the HER2-positive GC TME is not clearly understood.

METHODS

To investigate the effect of HER2 signaling on the activation of the cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) pathway, which contributes to immune cell activation in the GC TME, we evaluated the associations among the expressions of HER2, cGAS-STING, and the number of CD8+ tumor-infiltrating lymphocytes (TIL) by considering HER2 heterogeneity in HER2-positive GC tissues. We also examined the effect of HER2 signaling on the activation of STING signaling in vitro using human HER2-positive GC cell lines.

RESULTS

The expression of HER2 is highly heterogeneous in HER2-positive GC tissues, and we found that the number of CD8+ TIL in HER2 high areas was significantly lower than that in HER2 low areas in HER2-positive GC tissues. Intriguingly, the tumor cell-intrinsic expression of STING, but not cGAS, was also significantly lower in the HER2 high areas than the HER2 low areas in HER2-positive GC tissues. Moreover, in vitro experiments, we demonstrated that the blockade of HER2 signaling increased the expression of STING and its target genes, including IFNB1, CXCL9/10/11, and CCL5, in HER2-positive GC cell lines.

CONCLUSIONS

Our results suggest that HER2 signaling might suppress immune cell activation in the GC TME by inhibiting STING signaling in tumor cells in HER2-positive GC.

A comprehensive appraisal of HER2 heterogeneity in HER2-amplified and HER2-low colorectal cancer

BACKGROUND

This study aimed to elucidate the clinicopathological and molecular features of HER2-amplified and HER2-low colorectal cancers (CRCs). We also characterised HER2 expression statuses in CRCs focusing on their intratumoral heterogeneity and alterations in metastatic lesions to establish practical HER2 status assessment.

METHODS

We evaluated 1009 CRCs for HER2 expression and HER2 amplification by immunohistochemistry and FISH, respectively, and correlated the results to clinicopathological and molecular data. For HER2-positive tumours, HER2 expression in metastatic lesions was also assessed.

RESULTS

Twenty-five HER2-amplified (2.5%) and 46 HER2-low tumours (4.6%) were identified. HER2-amplified tumours consistently lacked a mucinous component and HER2-low tumours tended to be in the right colon, but no other clinicopathological features were noted. KRAS, NRAS or BRAF mutations were detected in only two HER2-amplified tumours (8%), whereas 23 HER2-low tumours (50%) had one of these mutations. Most HER2-amplified and HER2-low tumours showed a homogeneous or mosaic HER2 expression pattern and a clustered heterogeneous expression pattern was rather rare. HER2 expression was maintained in most metastatic lesions in both HER2-amplified (93%) and HER2-low tumours (81%).

CONCLUSIONS

These results suggest that biopsy-based assessment of primary lesions is appropriate for the identification of CRC patients eligible for systemic HER2-targeted therapy.

Trastuzumab Combined With Ramucirumab and Paclitaxel in Patients With Previously Treated Human Epidermal Growth Factor Receptor 2-Positive Advanced Gastric or Gastroesophageal Junction Cancer

PURPOSE

Trastuzumab-containing chemotherapy is the recommended first-line regimen for human epidermal growth factor receptor 2 (HER2)-positive advanced gastric or gastroesophageal junction (G/GEJ) cancer. We evaluated the safety and efficacy of trastuzumab combined with ramucirumab and paclitaxel as second-line treatment for HER2-positive G/GEJ cancer.

PATIENTS AND METHODS

Patients with HER2-positive advanced G/GEJ cancer who progressed after first-line treatment with trastuzumab-containing chemotherapy were enrolled from five centers in the Republic of Korea. Patients were administered a 28-day cycle of trastuzumab (once on days 1, 8, 15, and 22: 2 mg/kg followed by 4 mg/kg loading dose), ramucirumab (once on days 1 and 15: 8 mg/kg), and paclitaxel (once on days 1, 8, and 15: dose level 1, 80 mg/m2; or dose level -1, 70 mg/m2). Phase II was conducted with the recommended phase II dose (RP2D). Primary end points were determination of RP2D during phase Ib and investigator-assessed progression-free survival (PFS) in patients treated with RP2D.

RESULTS

Dose-limiting toxicity at dose level 1 was not documented during phase Ib, and a full dose combination was selected as the RP2D. Among 50 patients with a median follow-up duration of 27.5 months (95% CI, 17.4 to 37.6), median PFS and overall survival were 7.1 months (95% CI, 4.8 to 9.4) and 13.6 months (95% CI, 9.4 to 17.7), respectively. Objective response rate was 54% (27 of 50, including one complete response), and disease control rate was 96% (48 of 50). Loss of HER2 expression was observed in 34.8% (8 of 23) patients after first-line treatment, and no definite association between HER2 expression and the outcome was revealed. Safety profiles were consistent with previous reports.

CONCLUSION

Trastuzumab combined with ramucirumab and paclitaxel showed appreciable efficacy with manageable safety profiles in patients with previously treated HER2-positive G/GEJ cancer.

Targeted and Immunotherapy Approaches in HER2-Positive Gastric and Gastroesophageal Junction Adenocarcinoma: A New Era

HER2-targeted therapy with the HER2 monoclonal antibody trastuzumab has achieved impressive outcomes in the first-line settings of patients with advanced gastric and gastroesophageal junction (GEJ) adenocarcinoma overexpressing HER2. However, considering that a substantial proportion of those patients eventually relapses, as well as the relatively limited performance of those agents in second-line settings, a deeper understanding of resistance mechanisms is needed for enhanced guidance for patients' therapeutic selection in the second-line setting and beyond. In this review, we highlight trastuzumab's (HER2-targeting agent) performance in patients with gastric or GEJ cancer, with insight into mechanisms of resistance. We also discuss the new integration of PD-1 inhibitor pembrolizumab into the trastuzumab for gastric cancer frontline regimen, the latest addition of trastuzumab deruxtecan to the treatment armamentarium, and the potential of pipeline HER2-targeting approaches and combinations in patients with gastric or GEJ adenocarcinoma.

Prognostic Model of D2 Radical Gastrectomy Combined with Neoadjuvant Chemotherapy for Gastric Cancer

Purpose

The AJCC (the American Joint Committee on Cancer) ypTNM (post-neoadjuvant pathologic stage group) staging was established based on patients with lymphadenectomy scope less than D2 and did not include ypT0N0 patients with pathologically complete response (PCR). The purpose of this study was to construct a survival predictive model for gastric cancer patients after neoadjuvant chemotherapy and gastrectomy combined with D2 lymphadenectomy.

Patients and Methods

The multicenter data of 838 gastric cancer patients who received neoadjuvant chemotherapy and gastrectomy combined with D2 lymphadenectomy were analyzed retrospectively. These dual center patients were divided into training (n = 671, the Affiliated Hospital of Qingdao University) and validation (n = 167, Qingdao West Coast New Area Central Hospital) cohorts. Based on training cohort, univariate and multivariable COX regression analyses were performed to select the clinicopathological characteristics significantly correlating with overall survival and construct a nomogram. Based on training and validation cohorts, the distinguishing and calibrating capabilities of nomogram was evaluated by the receiver operating characteristic (ROC) curve, Harrell's concordance index (C-index), decision curve analysis (DCA) curve and calibration curve.

Results

Platelet-to-lymphocyte ratio (PLR), pathologic stage after neoadjuvant treatment: ypT and ypN stage, tumor regression grade (TRG) became independent variables intimately related to the prognosis and was used to construct nomograms of 3/5-year prognosis. The nomograms showed an accuracy in predicting OS (overall survival) rate, with area under the ROC curve (AUC) of 0.818 (95% CI = 0.753~0.883) and C-index of 0.801 (95% CI = 0.744~0.858) in validation cohort. Calibration curves showed satisfactory agreement between nomogram prediction and actual result, and DCA curves indicated the large positive net benefit and excellent clinical usefulness of nomogram.

Conclusion

This study successfully developed a nomogram to predict overall survival of gastric cancer patients after neoadjuvant chemotherapy and gastrectomy combined with D2 lymphadenectomy, which might have excellent predictive performance and clinical application value.

Gastric cancer treatment: recent progress and future perspectives

Gastric cancer (GC) is one of the most common malignancies worldwide. Most patients are diagnosed at advanced stages due to the subtle symptoms of earlier disease and the low rate of regular screening. Systemic therapies for GC, including chemotherapy, targeted therapy and immunotherapy, have evolved significantly in the past few years. For resectable GC, perioperative chemotherapy has become the standard treatment. Ongoing investigations are exploring the potential benefits of targeted therapy or immunotherapy in the perioperative or adjuvant setting. For metastatic disease, there have been notable advancements in immunotherapy and biomarker-directed therapies recently. Classification based on molecular biomarkers, such as programmed cell death ligand 1 (PD-L1), microsatellite instability (MSI), and human epidermal growth factor receptor 2 (HER2), provides an opportunity to differentiate patients who may benefit from immunotherapy or targeted therapy. Molecular diagnostic techniques have facilitated the characterization of GC genetic profiles and the identification of new potential molecular targets. This review systematically summarizes the main research progress in systemic treatment for GC, discusses current individualized strategies and presents future perspectives.

HER2 Intratumoral Heterogeneity in Breast Cancer, an Evolving Concept

Amplification and/or overexpression of human epidermal growth factor receptor 2 (HER2) in breast cancer is associated with an adverse prognosis. The introduction of anti-HER2 targeted therapy has dramatically improved the clinical outcomes of patients with HER2-positive breast cancer. Unfortunately, a significant number of patients eventually relapse and develop distant metastasis. HER2 intratumoral heterogeneity (ITH) has been reported to be associated with poor prognosis in patients with anti-HER2 targeted therapies and was proposed to be a potential mechanism for anti-HER2 resistance. In this review, we described the current definition, common types of HER2 ITH in breast cancer, the challenge in interpretation of HER2 status in cases showing ITH and the clinical applications of anti-HER2 agents in breast cancer showing heterogeneous HER2 expression. Digital image analysis has emerged as an objective and reproducible scoring method and its role in the assessment of HER2 status with ITH remains to be demonstrated.

Comprehensive biomarker analysis of long-term response to trastuzumab in patients with HER2-positive advanced gastric or gastroesophageal adenocarcinoma

BACKGROUND

A subgroup of patients with HER2-positive metastatic gastric and gastroesophageal junction cancers shows long-term response under trastuzumab maintenance monotherapy. Obviously, HER2 status alone is not able to identify these patients. We performed this study to identify potential new prognostic biomarkers for this long-term responding patient group.

PATIENTS AND METHODS

Tumour samples of 19 patients with HER2-positive metastatic gastric and gastroesophageal junction cancer who underwent trastuzumab treatment were retrospectively collected from multiple centres. Patients were divided into long-term responding (n = 7) or short-term responding group (n = 12) according to progression-free survival (PFS≥12 months vs. PFS < 12 months). Next-generation sequencing and microarray-based gene expression analysis were performed along with HER2 and PD-L1 immunohistochemistry.

RESULTS

Long-term responding patients had significantly higher PD-L1 combined positive scores (CPS) and CPS correlated with longer progression-free survival. PD-L1 positivity (CPS ≥ 1) was further associated with an increased CD4+ memory T-cell score. The ERBB2 copy number as well as the tumour mutational burden could not discriminate between short-term and long-term responding patients. Genetic alterations and coamplifications in HER2 pathway associated genes such as EGFR, which were connected to trastuzumab resistance, were present in 10% of the patients and equally distributed between the groups.

CONCLUSION

The study highlights the clinical relevance of PD-L1 testing also in the context of trastuzumab treatment and offers a biological rational by demonstrating elevated CD4+ memory T-cells scores in the PD-L1-positive group.

Deviating HER2 test results in gastric cancer: analysis from the prospective multicenter VARIANZ study

PURPOSE

The prospective multicenter VARIANZ study aimed to identify resistance biomarkers for HER2-targeted treatment in advanced gastric and esophago-gastric junction cancer (GC, EGJC). HER2 test deviations were found in 90 (22.3%) of 404 cases (central versus local testing) and were associated with negative impact on survival for trastuzumab-treated patients. Here, we investigated methodological and biological variables that may promote deviating HER2 test results.

METHODS

We analyzed HER2 testing procedures and participation in quality assurance programs of 105 participating local pathology laboratories. Furthermore, tumor localization and histological subtypes were compared between patients with centrally confirmed (central HER2 + /local HER2 + , n = 68) and unconfirmed HER2 status (central HER2 -/local HER2 + , n = 68).

RESULTS

For central HER2 testing, concordance between in situ hybridization (ISH) and immunohistochemistry (IHC) was 98.3%, with IHC sensitivity of 93.3% (84 IHC + of 90 ISH +), specificity of 99.5% (389 IHC- of 391 ISH-), and a positive diagnosis rate of 97.7%. Central confirmation of the local HER2 IHC scores were seen for the majority of locally HER2- IHC 0/1 (172/178; 96.6%), but less frequently for locally IHC3 + (57/124; 46.0%) cases. Deviation rate was not associated with IHC antibody platform used in the local pathology institute neither with participation in quality-assuring tests. Regarding tumor characteristics, deviating test results were more frequently found in GC vs. EGJC (69.1% vs. 39.7%; p = 0.001) and in Laurén diffuse vs. intestinal subtype (23.5% vs. 5.9%, p = 0.004).

CONCLUSION

Tumor localization and histological subtype have an impact on HER2 test deviation rates. Assessment of HER2 remains challenging for GC and EGJC.

Predictive biomarkers in gastric cancer

Predictive biomarkers are the mainstay of precision medicine. This review summarizes the advancements in tissue-based diagnostic biomarkers for gastric cancer, which is considered the leading cause of cancer-related deaths worldwide. A disease seen in the elderly, it is often diagnosed at an advanced stage, thereby limiting therapeutic options. In Western countries, neoadjuvant/perioperative (radio-)chemotherapy is administered, and adjuvant chemotherapy is administered in the East. The morpho-molecular classification of gastric cancer has opened novel avenues identifying Epstein-Barr-Virus (EBV)-positive, microsatellite instable, genomically stable and chromosomal instable gastric cancers. In chromosomal instable tumors, receptor tyrosine kinases (RKTs) (e.g., EGFR, FGFR2, HER2, and MET) are frequently overexpressed. Gastric cancers such as microsatellite instable and EBV-positive types often express immune checkpoint molecules, such as PD-L1 and VISTA. Genomically stable tumors show alterations in claudin 18.2. Next-generation sequencing is increasingly being used to search for druggable targets in advanced palliative settings. However, most tissue-based biomarkers of gastric cancer carry the risk of a sampling error due to intratumoral heterogeneity, and adequate tissue sampling is of paramount importance.

Current molecular biomarkers evaluation in gastric/gastroesophageal junction adenocarcinoma: pathologist does matter

The comprehensive molecular characterization of gastric and gastroesophageal junction adenocarcinomas has led to the improvement of targeted and more effective treatments. As a result, several biomarkers have been introduced into clinical practice and the implementation of innovative diagnostic tools is under study. Such assessments are mainly based on the evaluation of limited biopsy material in clinical practice. In this setting, the pathologist represents a key player in the selection of patients facilitating precision medicine approaches.

A CT-based radiomics signature for prediction of HER2 overexpression and treatment efficacy of trastuzumab in advanced gastric cancer

Background

Accurate evaluation of human epidermal growth factor receptor 2 (HER2) status is very important for appropriate management of advanced gastric cancer (AGC) patients. In this study, we aimed to develop and validate a computed tomography (CT)-based radiomics signature for preoperative prediction of HER2 overexpression and treatment efficacy of trastuzumab in AGC.

Methods

We retrospectively enrolled 536 consecutive AGC patients (median age, 59 years; interquartile range, 52-65 years; 377 male, 159 female) and separated them into a training set (n=357) and a testing set (n=179). Radiomic features were extracted from 3 different phase images of contrast-enhanced CT scans, and a radiomics signature was built based on highly reproducible features using the least absolute shrinkage and selection operator (LASSO) method. The predictive performance of the radiomics signature was assessed in the training and testing sets. Univariable and multivariable logistical regression analyses were used to identify independent risk factors of HER2 overexpression. Univariable and multivariable Cox regression analyses were used to identify the risk factors of overall survival (OS) and progression-free survival (PFS). The predictive value of the radiomics signature for treatment efficacy of trastuzumab was also evaluated.

Results

The radiomics signature comprised eight robust features that demonstrated good discrimination ability for HER2 overexpression in the training set [area under the curve (AUC) =0.85] and the testing set (AUC =0.81). Multivariable Cox regression analysis revealed that the radiomics signature was an independent risk factor for OS [hazard ratio (HR) =2.01, P=0.001] and PFS (HR =1.32, P=0.01). The radiomics score of patients who achieved disease control was significantly lower than that of patients with progressive disease (P=0.023).

Conclusions

The proposed radiomics signature showed favorable accuracy for prediction of HER2 overexpression and prognosis in AGC. It has promising potential as a noninvasive approach for selecting patients for target therapy.

A multiphase contrast-enhanced CT radiomics model for prediction of human epidermal growth factor receptor 2 status in advanced gastric cancer

Background: Accurate evaluation of human epidermal growth factor receptor 2 (HER2) status is of great importance for appropriate management of advanced gastric cancer (AGC) patients. This study aims to develop and validate a CT-based radiomics model for prediction of HER2 overexpression in AGC.

Materials and Methods: Seven hundred and forty-five consecutive AGC patients (median age, 59 years; interquartile range, 52–66 years; 515 male and 230 female) were enrolled and separated into training set (n = 521) and testing set (n = 224) in this retrospective study. Radiomics features were extracted from three phases images of contrast-enhanced CT scans. A radiomics signature was built based on highly reproducible features using the least absolute shrinkage and selection operator method. Univariable and multivariable logistical regression analysis were used to establish predictive model with independent risk factors of HER2 overexpression. The predictive performance of radiomics model was assessed in the training and testing sets.

Results: The positive rate of HER2 was 15.9% and 13.8% in the training set and testing set, respectively. The positive rate of HER2 in intestinal-type GC was significantly higher than that in diffuse-type GC. The radiomics signature comprised eight robust features demonstrated good discrimination ability for HER2 overexpression in the training set (AUC = 0.84) and the testing set (AUC = 0.78). A radiomics-based model that incorporated radiomics signature and pathological type showed good discrimination and calibration in the training (AUC = 0.85) and testing (AUC = 0.84) sets.

Conclusion: The proposed radiomics model showed favorable accuracy for prediction of HER2 overexpression in AGC.

Targeting HER2 in metastatic gastroesophageal adenocarcinomas: What is new?

Gastric and esophageal adenocarcinomas represent a biologically heterogeneous disease. The identification, in early eighties, of human epidermal growth factor receptor 2 (HER2) overexpression, being present in 12 to 20% of the cases, marked a major milestone in the efforts of unraveling the molecular complexity of this disease. This led to the development of anti-HER2-therapies, trastuzumab being the first to demonstrate, in combination with cisplatin and 5FU/capecitabine chemotherapy, an improvement in response rate and survival in the first-line setting of patients with metastatic, HER2-positive gastroesophageal adenocarcinomas. Afterwards, during a decade, several studies have tried new strategies either to block HER2 pathway differently or to combine different anti-HER2, without efficacy. Everything changed with studies demonstrating additive effect between anti-HER2 and immune checkpoint inhibitors and leading to phase III clinical trials combining anti-HER2 and anti-PD-L1/PD1 therapies. Pembrolizumab, a PD-1 inhibitor, was recently granted by FDA an accelerated approval, in patients with HER2-positive gastro-oesophageal adenocarcinomas, in combination with trastuzumab and platinum-based chemotherapy following meaningful improvement in overall response rate over standard treatment. Progression-free and overall-survival results are still awaited to change our first-line standard treatment. Furthermore, new HER2 inhibitors have been developed, blocking HER2-mediated pathway signaling via different mechanisms from pan-HER inhibition to anti-HER2 antibody drug conjugates with promising results in pretreated patients. Trastuzumab-deruxtecan has in particular showed interesting results in pretreated patients. We present here a review of the recent data and perspectives in HER2-positive metastatic gastroesophageal adenocarcinomas.

Molecular Pathology of Gastric Cancer

Gastric cancer (GC) is one of the most common lethal malignant neoplasms worldwide, with limited treatment options for both locally advanced and/or metastatic conditions, resulting in a dismal prognosis. Although the widely used morphological classifications may be helpful for endoscopic or surgical treatment choices, they are still insufficient to guide precise and/or personalized therapy for individual patients. Recent advances in genomic technology and high-throughput analysis may improve the understanding of molecular pathways associated with GC pathogenesis and aid in the classification of GC at the molecular level. Advances in next-generation sequencing have enabled the identification of several genetic alterations through single experiments. Thus, understanding the driver alterations involved in gastric carcinogenesis has become increasingly important because it can aid in the discovery of potential biomarkers and therapeutic targets. In this article, we review the molecular classifications of GC, focusing on The Cancer Genome Atlas (TCGA) classification. We further describe the currently available biomarker-targeted therapies and potential biomarker-guided therapies. This review will help clinicians by providing an inclusive understanding of the molecular pathology of GC and may assist in selecting the best treatment approaches for patients with GC.

HER2-targeted advanced metastatic gastric/gastroesophageal junction adenocarcinoma: treatment landscape and future perspectives

Recently, the global incidence of gastric/gastroesophageal junction (G/GEJ) cancer has remained high. China is also a large country with a high gastric cancer (GC) incidence rate, where the cases of GC account for 40% of all cases worldwide. More than 90% of GEJ cancers are the adenocarcinoma pathological type. Patients with early-stage G/GEJ adenocarcinoma may have a better prognosis after surgery. In contrast, patients with advanced metastatic G/GEJ adenocarcinoma usually choose comprehensive treatment based on systemic pharmacotherapy, but the subsequent long-term survival is not optimistic. The discovery of various biomarkers, especially microsatellite instability (MSI), programmed cell death-ligand 1 (PD-L1), human epidermal growth factor receptor 2 (HER2), tumor mutational burden (TMB) and Epstein-Barr virus (EBV), has led to the identification of an increasing number of targeted populations and has greatly improved the clinical efficacy of treatments for G/GEJ adenocarcinoma. The ToGA trial added trastuzumab to standard chemotherapy, showed improved survival of patients with HER2-positive advanced G/GEJ adenocarcinoma and brought these patients into a new era of HER2-targeted therapy. Moreover, many HER2-targeted agents have been developed and studied in patients with advanced HER2-positive G/GEJ adenocarcinoma who have demonstrated excellent clinical outcomes. However, many patients experience disease progression with HER2-targeted therapy; hence, new anti-HER2 drugs keep being developed, significantly reducing HER2 resistance. This paper reviews HER2-targeted drugs for advanced metastatic G/GEJ adenocarcinoma, potential resistance mechanisms and future directions.

HER2 Inhibition in Gastric Cancer-Novel Therapeutic Approaches for an Established Target

Gastric cancer is a leading cause of cancer-related deaths globally. Human epidermal growth receptor 2 (HER2) overexpression of HER2 gene amplification is present in 20% of gastric cancers and defines a subset amenable to HER2-directed therapeutics. The seminal ToGA study led to routine use of the monoclonal antibody trastuzumab in conjunction to platinum-fluoropyridimine first-line chemotherapy for HER2-positive gastric cancers as standard-of-care. Although limited progress was made in the decade following ToGA, there is now an abundance of novel therapeutic approaches undergoing investigation in parallel. Additionally, new data from randomised trials have indicated efficacy of the antibody-drug conjugate trastuzumab deruxtecan in chemorefractory patients and increased responses with the addition of first-line immune checkpoint blockade to trastuzumab and chemotherapy. This review will outline the data supporting HER2 targeting in gastric cancers, discuss mechanisms of response and resistance to HER2-directed therapies and summarise the emerging therapies under clinical evaluation that may evolve the way we manage this subset of gastric cancers in the future.

Association between HER2 heterogeneity and clinical outcomes of HER2-positive gastric cancer patients treated with trastuzumab

BACKGROUND

The GASTHER1 study showed that re-evaluation of HER2 status rescued 8% of HER2-positive gastric cancer (GC) patients with initially HER2-negative GC. Since rescued HER2 positivity represents HER2 heterogeneity, we aimed to investigate this in a larger cohort with longer follow-up duration.

METHODS

Data of 153 HER2-positive advanced GC patients who received first-line trastuzumab-based chemotherapy were analyzed. Repeat endoscopic biopsy was performed in patients with initially HER2-negative GC. Survival outcomes were analyzed according to the immunohistochemistry (IHC) score (IHC 2+ /in situ hybridization [ISH] + vs IHC 3+), HER2 status (initially vs rescued HER2 positive), and H-score.

RESULTS

IHC 2+ /ISH + patients showed worse progression-free survival (PFS) and overall survival (OS) than those with IHC 3+ (p < 0.05). Rescued HER2-positive patients showed worse PFS and OS than initially HER2-positive patients (p < 0.05). Although survival outcomes were comparable according to HER2 status in IHC 2+ /ISH + patients, initially HER2-positive patients showed more favorable PFS and OS than rescued HER2-positive patients (p < 0.05) among those with IHC 3+ . Among the subgroups determined by HER2 status and IHC score, the initially IHC 3+ subgroup had the highest H-score. The low H-score group (H-score ≤ 210) had significantly worse survival outcomes than the high H-score group (H-score > 210) (p < 0.05). An H-score of ≤ 210 was independently associated with shorter OS (HR = 1.54, 95% CI 1.02-2.31, p = 0.04).

CONCLUSIONS

Rescued HER2-positive patients showed worse clinical outcomes than initially HER2-positive patients, especially those with IHC 3+ . This finding highlights the impact of HER2 heterogeneity, which can be quantified indirectly as an H-score.

Dual block HER2 assessment increased HER2 immunohistochemistry positive rate in resected specimens of gastric cancer: a prospective multicenter clinical trial from China

Background

Former single center studies indicated that HER2 assessment with two primary tumor blocks (dual block HER2 assessment) could be an efficient and practical approach to overcome the adverse impact of heterogeneity and acquire a HER2 positive rate in gastric cancer (GC). This multicenter prospective clinical trial (NCT 02843412) was launched to verify its value and generality.

Methods

A total of 3806 participants with primary GCs have been enrolled from 8 hospitals in China. Two primary tumor blocks were selected and recorded as block 1 and block 2 after histological evaluation. An HER2 (4B5) rabbit monoclonal antibody was used for the immunohistochemistry (IHC) analysis.

Results

In total patients, HER2 IHC positive (3+) rate with dual block assessment (9.4%) was higher than that with single block assessment (block 1: 7.8%, block 2: 7.8%) (P < 0.001). Compared with single-block assessment, dual-block assessment increased the positive rate by approximate 20%. Similarly, HER2 equivocal (2+) rate was increased in dual block assessment (25.8%), which was higher than that in single block assessment (block 1: 20.3%, block 2: 20.9%) (P < 0.001). Conversely, dual block assessment demonstrated a lower HER2 negative (0/1+) rate (64.8%) than single block assessment (block1: 71.9%, block 2: 71.3%) (P < 0.001). These findings were also confirmed in individual hospitals.

Conclusions

Dual block HER2 assessment effectively increased HER2 IHC positive rate in resected specimens of GC. We recommended dual block HER2 assessment be promoted in routine clinical practice in GC.

Trial registration

ClinicalTrials.gov, NCT 02843412. Registered 1 July 2016 - Retrospectively registered.

CD44v6 High Membranous Expression Is a Predictive Marker of Therapy Response in Gastric Cancer Patients

In gastric cancer (GC), biomarkers that define prognosis and predict treatment response remain scarce. We hypothesized that the extent of CD44v6 membranous tumor expression could predict prognosis and therapy response in GC patients. Two GC surgical cohorts, from Portugal and South Korea (n = 964), were characterized for the extension of CD44v6 membranous immuno-expression, clinicopathological features, patient survival, and therapy response. The value of CD44v6 expression in predicting response to treatment and its impact on prognosis was determined. High CD44v6 expression was associated with invasive features (perineural invasion and depth of invasion) in both cohorts and with worse survival in the Portuguese GC cohort (HR 1.461; 95% confidence interval 1.002–2.131). Patients with high CD44v6 tumor expression benefited from conventional chemotherapy in addition to surgery (p < 0.05), particularly those with heterogeneous CD44v6-positive and -negative populations (CD44v6_3+) (p < 0.007 and p < 0.009). Our study is the first to identify CD44v6 high membranous expression as a potential predictive marker of response to conventional treatment, but it does not clarify CD44v6 prognostic value in GC. Importantly, our data support selection of GC patients with high CD44v6-expressing tumors for conventional chemotherapy in addition to surgery. These findings will allow better stratification of GC patients for treatment, potentially improving their overall survival.

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.

Consensus recommendations for the standardized histopathological evaluation and reporting after radical oesophago-gastrectomy (HERO consensus)

BACKGROUND

Variation in the approach, radicality, and quality of gastroesophageal surgery impacts patient outcomes. Pathological outcomes such as lymph node yield are routinely used as surrogate markers of surgical quality, but are subject to significant variations in histopathological evaluation and reporting. A multi-society consensus group was convened to develop evidence-based recommendations for the standardized assessment of gastroesophageal cancer specimens.

METHODS

A consensus group comprised of surgeons, pathologists, and oncologists was convened on behalf of the Association of Upper Gastrointestinal Surgery of Great Britain & Ireland. Literature was reviewed for 17 key questions. Draft recommendations were voted upon via an anonymous Delphi process. Consensus was considered achieved where >70% of participants were in agreement.

RESULTS

Consensus was achieved on 18 statements for all 17 questions. Twelve strong recommendations regarding preparation and assessment of lymph nodes, margins, and reporting methods were made. Importantly, there was 100% agreement that the all specimens should be reported using the Royal College of Pathologists Guidelines as the minimum acceptable dataset. In addition, two weak recommendations regarding method and duration of specimen fixation were made. Four topics lacked sufficient evidence and no recommendation was made.

CONCLUSIONS

These consensus recommendations provide explicit guidance for gastroesophageal cancer specimen preparation and assessment, to provide maximum benefit for patient care and standardize reporting to allow benchmarking and improvement of surgical quality.

Biomarker-targeted therapies for advanced-stage gastric and gastro-oesophageal junction cancers: an emerging paradigm

Advances in cancer biology and sequencing technology have enabled the selection of targeted and more effective treatments for individual patients with various types of solid tumour. However, only three molecular biomarkers have thus far been demonstrated to predict a response to targeted therapies in patients with gastric and/or gastro-oesophageal junction (G/GEJ) cancers: HER2 positivity for trastuzumab and trastuzumab deruxtecan, and microsatellite instability (MSI) status and PD-L1 expression for pembrolizumab. Despite this lack of clinically relevant biomarkers, distinct molecular subtypes of G/GEJ cancers have been identified and have informed the development of novel agents, including receptor tyrosine kinase inhibitors and monoclonal antibodies, several of which are currently being tested in ongoing trials. Many of these trials include biomarker stratification, and some include analysis of circulating tumour DNA (ctDNA), which both enables the noninvasive assessment of biomarker expression and provides an indication of the contributions of intratumoural heterogeneity to response and resistance. The results of these studies might help to optimize the selection of patients to receive targeted therapies, thus facilitating precision medicine approaches for patients with G/GEJ cancers. In this Review, we describe the current evidence supporting the use of targeted therapies in patients with G/GEJ cancers and provide guidance on future research directions.

HER2-targeted therapies in gastric cancer

Molecular targeted therapy of cancer has always been the focus of clinicians. Among those therapeutic targets, the human epidermal growth factor receptor-2 (HER-2) signaling pathway is one of the most popular targets for translational research in cancer. However, unlike prospect in breast cancer, HER-2 inhibitor trastuzumab is the only molecular targeted drug approved by US Food and Drug Administration (FDA) for the first-line treatment of HER-2 positive advanced gastric cancer. On this basis, a variety of novel HER2- targeted drugs for gastric cancer are under development, and related clinical researches are in full swing, including small molecular kinase inhibitors (e.g., afatinib, neratinib, pyrotinib), antibody-drug conjugates (e.g., DS-8201a, RC48-ADC) and other novel therapies (e.g., ZW25, CAR-T, BVAC-B). In this study, we will summarize the recent advances in anti-HER-2 agents, potential mechanisms of resistance to HER2-targeted therapy in HER2-positive gastric cancer. We will also discuss the future prospects of potential strategies to overcome anti-HER-2 resistance and development of novel anti-HER-2 approaches for the treatment of HER2-positive gastric cancer patients.

HER2 Expression, Test Deviations, and Their Impact on Survival in Metastatic Gastric Cancer: Results From the Prospective Multicenter VARIANZ Study

Trastuzumab is the only approved targeted drug for first-line treatment of human epidermal growth factor receptor 2–positive (HER2+) metastatic gastric cancer (mGC). However, not all patients respond and most eventually progress. The multicenter VARIANZ study aimed to investigate the background of response and resistance to trastuzumab in mGC.

Beyond the Guidelines: The Grey Zones of the Management of Gastric Cancer. Consensus Statements from the Gastric Cancer Italian Network (GAIN)

BACKGROUND

Management of gastric and gastroesophageal junction (GEJ) adenocarcinoma remains challenging, because of the heterogeneity in tumor biology within the upper gastrointestinal tract. Daily clinical practice is full of grey areas regarding the complexity of diagnostic, staging, and therapeutic procedures. The aim of this paper is to provide a guide for clinicians facing challenging situations in routine practice, taking a multidisciplinary consensus approach based on available literature.

METHODS

The GAIN (GAstric cancer Italian Network) group was established with the aims of reviewing literature evidence, discussing key issues in prevention, diagnosis, and management of gastric and GEJ adenocarcinoma, and offering a summary of statements. A Delphi consensus method was used to obtain opinions from the expert panel of specialists.

RESULTS

Forty-nine clinical questions were identified in six areas of interest: role of multidisciplinary team; risk factors; diagnosis; management of early gastric cancer and multimodal approach to localized gastric cancer; treatment of elderly patients with locally advanced resectable disease; and treatment of locally advanced and metastatic cancer.

CONCLUSIONS

The statements presented may guide clinicians in practical management of this disease.

The impact of recent next generation sequencing and the need for a new classification in gastric cancer

The phenotypical and molecular heterogeneity of gastric cancer has hampered the introduction in clinical practice of a unifying classification of the disease. However, as next generation sequencing (NGS) technologies enhanced the comprehension of the molecular landscape of gastric cancer, novel molecular classification systems have been proposed, allowing the dissection of molecular tumor heterogeneity and paving the way for the development of new targeted therapies. Moreover, the use of NGS analyses in the molecular profiling of formalin-fixed paraffin-embedded (FFPE) specimens will improve patient selection for the enrolment in novel clinical trials. In conclusion, the application of NGS in precision oncology will revolutionize the diagnosis and clinical management in gastric cancer patients.

Human epidermal growth factor receptor 2 overexpression is frequently discordant between primary and metastatic urothelial carcinoma and is associated with intratumoral human epidermal growth factor receptor 2 heterogeneity

Human epidermal growth factor receptor 2 (HER2) overexpression occurs in 5-10% of primary urothelial carcinomas (UCs) but has not reliably predicted benefit from HER2-targeted agents in the metastatic setting. HER2 testing of primary tumors may not reflect the HER2 status of distant metastases. We assessed the concordance of HER2 expression in paired primary and distant metastatic UC lesions. Specimens from 149 patients with metastatic UC underwent immunohistochemical staining for HER2, including 79 paired primary and distant metastatic tumors. HER2 status was defined using 2018 ASCO/CAP guidelines. HER2 intratumoral heterogeneity (ITH) was defined as HER2 3+ expression in 5-50% of tumor cells. The HER2-positive, -equivocal, and -negative rates observed were 10.6%, 24.7%, and 64.7% for primary tumors and 9.8%, 12.6%, and 77.6% for metastatic tumors, respectively. HER2 ITH occurred in 44% of HER2-positive primary tumors. Low agreement of HER2-positive status between primary and metastatic tumors was observed (к = 0.193, P = 0.079). Loss of HER2 overexpression in the metastatic lesion was observed in 55% (5 of 9 cases) of HER2-positive primary cases and was associated with the presence of HER2 ITH in the primary tumor (Fisher's exact P = 0.048). Change from negative primary to positive metastasis was seen in 2% (1 of 50) of cases. No differences in metastasis-free survival or overall survival were observed in accordance with HER2 status defined by either the primary or metastatic lesion. These findings are likely to impact patient selection for HER2 targeted therapies in UC. Confirmation and evaluation of the clinical significance of HER2 discordance is warranted, preferably in the context of a clinical trial.

Clinical outcomes of radical gastrectomy following trastuzumab-based chemotherapy for stage IV HER2-positive gastric or gastroesophageal junction cancer

PURPOSE

Patients who receive trastuzumab (T-mab) plus chemotherapy for stage IV HER2-positive gastric or gastroesophageal junction cancer sometimes respond remarkably well and can undergo radical surgery. However, the clinical outcomes of preoperative T-mab combined chemotherapy with radical gastrectomy remain unclear. We conducted this study to investigate the clinical outcomes of this multimodal treatment.

METHODS

From among a total of 199 patients who received T-mab-based chemotherapy for stage IV HER2-positive gastric or gastroesophageal junction cancer between 2011 and 2018, the subjects of this retrospective analysis were 20 patients who subsequently underwent radical gastrectomy.

RESULTS

Seven patients had gastroesophageal junction cancer and 13 had gastric cancer. Eleven patients had unresectable stage IV cancer and 9 had resectable metastatic disease. Chemotherapy regimens included capecitabine, cisplatin + T-mab (11 patients), and S-1, oxaliplatin + T-mab (nine patients). The median number of chemotherapy cycles before surgery was three (range, 2-62). During preoperative chemotherapy, grade 3/4 adverse events developed in six patients. None suffered grade ≥ 3b postoperative complications. The 3-year relapse-free survival (RFS) and overall survival (OS) rates were 58.9% and 89.5%, respectively.

CONCLUSION

Combined preoperative T-mab-based chemotherapy and surgery appears to be safe and effective for stage IV HER2-positive gastric or gastroesophageal junction cancer, with a clinically meaningful impact on RFS and OS.

Effectiveness of Trastuzumab in Routine Clinical Practice: A Population-based Study of Patients with HER-2-positive Oesophageal, Gastroesophageal and Gastric Cancer

AIMS

In the pivotal Trastuzumab for Gastric Cancer (ToGA) trial, trastuzumab improved median survival in patients with advanced HER-2-positive gastric and gastroesophageal cancer from 11.1 to 13.8 months; however, its effectiveness in routine clinical practice has not been evaluated. Our objective was to evaluate the uptake and outcomes of trastuzumab in a population-based cohort of patients with oesophageal, gastroesophageal and gastric cancer in Ontario, Canada.

MATERIALS AND METHODS

The Ontario Cancer Registry and linked treatment records were used to identify all patients with oesophageal, gastroesophageal and gastric cancer treated with trastuzumab during 2012-2017. Outcomes were analysed from the time of first trastuzumab cycle and included a primary outcome (survival) and secondary outcomes (uptake, delivery, 30-day hospital admission and 30-day mortality). Trends over the study period and survival were evaluated.

RESULTS

In total, 476 patients with oesophageal, gastroesophageal and gastric cancer received trastuzumab during the study period. The mean age was 62 years, 78% (370/476) were male, and 65% (312/476) had gastric cancer. The annual number of patients receiving trastuzumab increased over the study period (53 in 2012 and 101 in 2017). The median number of cycles of trastuzumab delivered was six. Thirty-day hospital admission and mortality rates were 17% and 4%, respectively. The median overall survival was 282 days (9.3 months).

CONCLUSIONS

The median survival of patients treated with trastuzumab for advanced oesophageal, gastroesophageal and gastric cancer in routine practice is substantially less than that observed in the pivotal clinical trial. Studies of comparative effectiveness using real-world data offer insight into outcomes achieved in routine practice.

HER2 Heterogeneity in Personalized Therapy of Gastro-Oesophageal Malignancies: An Overview by Different Methodologies

Human epidermal growth factor receptor-2 (HER2)-expression gastro-oesophageal adenocarcinomas (GEA) gained interest as an important target for therapy with trastuzumab. In the current review, we focused the current knowledge on HER2 status in dysplastic and neoplastic gastric conditions, analyzing the methodological procedures to identify HER2 expression/amplification, as well as the proposed scoring recommendations. One of the most relevant questions to evaluate the useful impact of HER2 status on therapeutic choice in GEAs is represented by the significant heterogeneity of HER2 protein and gene expression that may affect the targeted treatment selection. Future development of biotechnology will continue to evolve in order to offer more powerful detection systems for the assessment of HER2 status. Finally, liquid biopsy as well as mutation/amplification of several additional genes may furnish an early detection of secondary HER2 resistance mechanisms in GEAs with a better monitoring of the treatment response.

De novo discovery of metabolic heterogeneity with immunophenotype-guided imaging mass spectrometry

Imaging mass spectrometry enables in situ label-free detection of thousands of metabolites from intact tissue samples. However, automated steps for multi-omics analyses and interpretation of histological images have not yet been implemented in mass spectrometry data analysis workflows. The characterization of molecular properties within cellular and histological features is done via time-consuming, non-objective, and irreproducible definitions of regions of interest, which are often accompanied by a loss of spatial resolution due to mass spectra averaging.

Methods: We developed a new imaging pipeline called Spatial Correlation Image Analysis (SPACiAL), which is a computational multimodal workflow designed to combine molecular imaging data with multiplex immunohistochemistry (IHC). SPACiAL allows comprehensive and spatially resolved in situ correlation analyses on a cellular resolution. To demonstrate the method, matrix-assisted laser desorption-ionization (MALDI) Fourier-transform ion cyclotron resonance (FTICR) imaging mass spectrometry of metabolites and multiplex IHC staining were performed on the very same tissue section of mouse pancreatic islets and on human gastric cancer tissue specimens. The SPACiAL pipeline was used to perform an automatic, semantic-based, functional tissue annotation of histological and cellular features to identify metabolic profiles. Spatial correlation networks were generated to analyze metabolic heterogeneity associated with cellular features.

Results: To demonstrate the new method, the SPACiAL pipeline was used to identify metabolic signatures of alpha and beta cells within islets of Langerhans, which are cell types that are not distinguishable via morphology alone. The semantic-based, functional tissue annotation allows an unprecedented analysis of metabolic heterogeneity via the generation of spatial correlation networks. Additionally, we demonstrated intra- and intertumoral metabolic heterogeneity within HER2/neu-positive and -negative gastric tumor cells.

Conclusions: We developed the SPACiAL workflow to provide IHC-guided in situ metabolomics on intact tissue sections. Diminishing the workload by automated recognition of histological and functional features, the pipeline allows comprehensive analyses of metabolic heterogeneity. The multimodality of immunohistochemical staining and extensive molecular information from imaging mass spectrometry has the advantage of increasing both the efficiency and precision for spatially resolved analyses of specific cell types. The SPACiAL method is a stepping stone for the objective analysis of high-throughput, multi-omics data from clinical research and practice that is required for diagnostics, biomarker discovery, or therapy response prediction.

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Novel method enables phenotype-guided in situ metabolomics on intact tissue sections.

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Metabolic heterogeneity can be objectified under (patho-)physiological conditions.

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Innovative approach for tissue-based, preclinical, and clinical research.

Emerging Targeted Therapies for HER2 Positive Gastric Cancer That Can Overcome Trastuzumab Resistance

Trastuzumab, a monoclonal antibody to human epidermal growth factor receptor 2 (HER2), has improved survival in patients with HER2-positive advanced gastric or gastroesophageal junction cancer (AGC). The inevitable development of resistance to trastuzumab remains a problem, however, with several treatment strategies that have proven effective in breast cancer having failed to show clinical benefit in AGC. In this review, we summarize the mechanisms underlying resistance to HER2-targeted therapy and outline past and current challenges in the treatment of HER2-positive AGC refractory to trastuzumab. We further describe novel agents such as HER2 antibody-drug conjugates that are under development and have shown promising antitumor activity in early studies.

Late stage gastric cancer patients with extra gained HER2 positivity by dual block assessment may not show compromised efficacy to trastuzumab treatment

Dual block HER2 assessment can effectively increase the HER2 positive rate in resected specimens of gastric cancer (GC). The aim of this study is to explore whether GC patients with extra gained HER2 positivity by dual block assessment can benefit from trastuzumab therapy. Twenty-eight GC patients receiving gastrectomy prior to trastuzumab treatment were retrospectively analyzed. All the cases routinely accepted dual block HER2 assessment. The cases were divided into 2 cohorts based on HER2 status: cohort A with concordant HER2 results and cohort B with discordant HER2 results between the two blocks (cases with extra gained HER2 positivity). Response rate (RR), progress free survival (PFS) and overall survival (OS) were compared between the two cohorts. The results showed that no significant differences were found between the two cohorts in main clinicopathologic characteristics. No statistical difference was found in response rate (47.6% vs 57.1%) (P=1.0), either. The two cohorts did not demonstrate statistical differences in the PFS (10.5 months (95%CI 6.4-14.6) vs 8.0 months (95%CI 3.2-12.8), P=0.686) and the OS (23.3 months (95%CI 12.1-34.5) vs 20.0 months (95%CI 10.1-29.9), P=0.776). In conclusion, our study suggests that patients with extra gained HER2 positivity may not show compromised efficacy to trastuzumab treatment.

Multicenter phase II study of trastuzumab with S-1 plus oxaliplatin for chemotherapy-naïve, HER2-positive advanced gastric cancer

BACKGROUND

Trastuzumab with cisplatin and fluoropyrimidines improves overall survival (OS) in patients with HER2-positive advanced gastric cancer (AGC). S-1 plus oxaliplatin (SOX) is one of the standard regimens for HER2-negative AGC in Japan. However, few studies have evaluated trastuzumab combined with SOX in patients with HER2-positive AGC.

METHODS

This was a multicenter, phase II study conducted at 10 institutions in Japan. Patients with HER2-positive AGC received S-1 twice a day on days 1-14 and oxaliplatin and trastuzumab on day 1 of a 21-day cycle. The primary endpoint was the confirmed overall response rate (ORR), and the secondary endpoints were OS, progression-free survival (PFS), and safety. The sample size was 75 to have 90% power with an alpha error of 0.1 (one-sided), expecting an ORR of 65% and threshold of 50%.

RESULTS

From June 2015 to January 2018, 75 patients were enrolled. The ORR was 70.7% [95% confidence interval (CI) 59.0-80.6]. The median OS and PFS were estimated as 18.1 months (95% CI 15.6-26.5) and 8.8 months (95% CI 7.4-12.2), respectively. The major grade 3 or 4 adverse events were sensory neuropathy (16.0%) and neutropenia (10.7%).

CONCLUSIONS

Trastuzumab with SOX had promising activity with well-tolerated toxicities for patients with HER2-positive AGC.

CLINICAL TRIAL REGISTRATION

UMIN000017602.

HER2 heterogeneity is a poor prognosticator for HER2-positive gastric cancer

BACKGROUND

The clinical significance of intratumoral human epidermal growth factor receptor 2 (HER2) heterogeneity is unclear for HER2-positive gastric cancer, although it has been reported to be a significant prognosticator for HER2-positive breast cancer, which has received trastuzumab-based chemotherapy.

AIM

To clarify the clinical significance of intratumoral HER2 heterogeneity for HER2-positive gastric cancer, which has received trastuzumab-based chemotherapy.

METHODS

Patients with HER2-positive unresectable or metastatic gastric cancer who received trastuzumab-based chemotherapy as a first line treatment were included. The patients were classified into two groups according to their intratumoral HER2 heterogeneity status examined by immunohistochemistry (IHC) on endoscopic biopsy specimens before treatment, and their clinical response to chemotherapy and survival were compared.

RESULTS

A total of 88 patients were included in this study, and HER2 heterogeneity was observed in 23 (26%) patients (Hetero group). The overall response rate was significantly better in patients without HER2 heterogeneity (Homo group) (Homo vs Hetero: 79.5% vs 35.7%, P = 0.002). Progression-free survival of trastuzumab-based chemotherapy was significantly better in the Homo group (median, 7.9 vs 2.5 mo, HR: 1.905, 95%CI: 1.109-3.268). Overall survival was also significantly better in the Homo group (median survival time, 25.7 vs 12.5 mo, HR: 2.430, 95%CI: 1.389-4.273). Multivariate analysis revealed IHC HER2 heterogeneity as one of the independent poor prognostic factors (HR: 3.115, 95%CI: 1.610-6.024).

CONCLUSION

IHC of HER2 heterogeneity is the pivotal predictor for trastuzumab-based chemotherapy. Thus, HER2 heterogeneity should be considered during the assessment of HER2 expression.