HER2 Heterogeneity in Gastroesophageal Cancer Detected by Testing Biopsy and Resection Specimens

HER2 expression and relevant clinicopathological features in esophageal squamous cell carcinoma in a Chinese population

Background

Despite great progress in surgery and other treatments, the prognosis of patients with esophageal squamous cell carcinoma (ESCC) is still very poor. HER2 has strong therapeutic implications in certain cancers, such as breast cancer and gastric cancer. However, literature on the frequency of HER2 expression in ESCC is scarce. In the present study, HER2 protein expression, HER2 gene amplification and the relationship between HER2 status and clinicopathological characteristics were evaluated in a large cohort of Chinese ESCC patients.

Methods

A total of 857 consecutive ESCC patients who received radical esophagectomy without neoadjuvant therapy between January 2014 and October 2015 were included in this retrospective study. HER2 protein expression was analyzed by immunohistochemistry (IHC), and its correlation with clinicopathological parameters was assessed. In addition, 65 cases, including 13 HER2 overexpression (3+) cases and 52 HER2 equivocal (2+) cases from the 857-case cohort, and another 104 ESCC cases, including 1 HER2 overexpression (3+) case, 3 HER2 equivocal (2+) cases and 100 HER2 negative (1+/0) cases, were selected to construct tissue microarrays (TMAs). Dual-color in situ hybridization (DISH) was performed on the TMAs to assess HER2 gene amplification and the relationship with clinicopathological parameters.

Results

We found HER2 overexpression (3+) status in 1.5% (13/857) of cases and HER2 equivocal (2+) status in 6.1% (52/857) of cases. HER2 IHC expression was significantly associated with gender (P = 0.028). However, there were no significant correlations between HER2 IHC expression and age, tumor differentiation, pT stage, pN stage, pM stage and pTNM stage (P > 0.05). Regarding the 169 cases analyzed by DISH, 14 (of 14, 100%) HER2 overexpression (3+) cases, 10 (of 55, 18.2%) HER2 equivocal (2+) cases, and 0 (of 100, 0%) HER2 negative (1+/0) cases showed HER2 gene amplification. HER2 gene amplification was not significantly associated with clinicopathological characteristics such as age, gender, tumor differentiation, pT stage, pN stage, pM stage and pTNM stage (P > 0.05).

Conclusions

Approximately 1.5% of the Chinese ESCC patients had HER2 overexpression based on IHC. IHC and DISH had a high concordance rate. These results provide valuable insight for the future treatment of ESCC.

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.

Increased assessment of HER2 in metastatic gastroesophageal cancer patients: a nationwide population-based cohort study

BACKGROUND

Addition of trastuzumab to first-line palliative chemotherapy in gastroesophageal cancer patients with HER2 overexpression has shown to improve survival. Real-world data on HER2 assessment and administration of trastuzumab are lacking. The aim of this study was to assess HER2 testing, trastuzumab administration, and overall survival (OS) in a nationwide cohort of metastatic gastroesophageal cancer patients.

METHODS

Data of patients with synchronous metastatic gastroesophageal adenocarcinoma diagnosed in 2010-2016 that received palliative systemic treatment (n = 2846) were collected from the Netherlands Cancer Registry and Dutch Pathology Registry. The ToGA trial criteria were used to determine HER2 overexpression. Proportions of HER2 tested patients were analyzed between hospital volume categories using Chi-square tests, and over time using trend analysis. OS was tested using the Kaplan Meier method with log rank test.

RESULTS

HER2 assessment increased annually, from 18% in 2010 to 88% in 2016 (P < 0.01). Median OS increased from 6.9 (2010-2013) to 7.9 months (2014-2016; P < 0.05). Between the hospitals, the proportion of tested patients varied between 29-100%, and was higher in high-volume hospitals (P < 0.01). Overall, 77% of the HER2 positive patients received trastuzumab. Median OS was higher in patients with positive (8.8 months) and negative (7.4 months) HER2 status, compared to non-tested patients (5.6 months; P < 0.05).

CONCLUSION

Increased determination of HER2 and administration of trastuzumab have changed daily practice management of metastatic gastroesophageal cancer patients receiving palliative systemic therapy, and possibly contributed to their improved survival. Further increase in awareness of HER2 testing and trastuzumab administration may improve quality of care and patient outcomes.

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.

Impact of Specimen Type and Specimen Number on HER2 Status in Gastroesophageal Junction and Gastric Adenocarcinoma

OBJECTIVES

Human epidermal growth factor receptor 2 (HER2) is expressed in some gastric and gastroesophageal junction adenocarcinomas. There were two goals: assess the impact of specimen type on HER2 status and evaluate HER2 concordance with multiple specimens.

METHODS

All cases were evaluated by immunohistochemistry (IHC) for HER2 and interpreted using established criteria. Fluorescence in situ hybridization (FISH) was performed on a subset.

RESULTS

Of 460 specimens, 83.9% were IHC negative, 5.4% were equivocal, and 10.7% were IHC positive. Of those with FISH testing, 78.5% were FISH negative, and 21.5% were FISH positive. IHC-FISH concordance for biopsy specimens, resections, and metastases was 82%, 84%, and 86%, respectively. With one vs two vs three or more specimens, the HER2-positive rate increased from 10.5% to 18.1% to 24.1%, respectively.

CONCLUSIONS

HER2 testing may be performed on biopsy specimens with a relatively high concordance rate with resection specimens, and if multiple samples are analyzed from a single patient, the HER2-positive rate increases over twofold.

HER2/neu (ERBB2) expression and gene amplification correlates with better survival in esophageal adenocarcinoma

BACKGROUND

HER2 (ERBB2 or HER2/neu) is a tyrosine-kinase increasing cell proliferation. Overexpression/amplification of HER2 is correlated with worse prognosis in solid malignancies. Consequently, HER2 targeting is established in breast and upper gastrointestinal tract cancer. There are conflicting data concerning the impact of HER2 overexpression on esophageal adenocarcinoma (EAC), as most studies do not differ between cancers of the esophagus/gastroesophageal junction and the stomach. The aim of this study was to analyze the expression/amplification of HER2 in EAC in correlation to clinicopathological data to verify its prognostic impact.

METHODS

We analyzed 428 EAC patients that underwent transthoracic thoraco-abdominal esophagectomy between 1997 and 2014. We performed HER2 immunohistochemistry (IHC) according to the guidelines and fluorescence-in-situ-hybridization (FISH) for IHC score2+, using tissue micro arrays (TMA) with up to eight biopsies from the surface and infiltration area of a single tumor for evaluating HER2-heterogeneity and single-spot TMA. The HER2-status was correlated with clinicopathological data.

RESULTS

HER2-positivity was found in up to 14.9% in our cohort (IHC score 3+ or IHC score 2+ with gene amplification) and demonstrated a significantly better overall survival (OS) in correlation to HER2-negative tumors (median OS 70.1 vs. 24.6 months, p = 0.006). HER2-overexpression was more frequently seen in lower tumor stages (pT1/pT2, p = 0.038), in the absence of lymphatic metastases (pN0/pN+, p = 0.020), and was significantly associated with better histological grading (G1/G2) (p = 0.041).

CONCLUSION

We demonstrated a positive prognostic impact of HER2 overexpression in a large cohort of EAC, contrary to other solid malignancies including gastric cancer and breast cancer, but consistent to the results of a large study on EAC from 2012.

Molecular biomarkers in gastro-esophageal cancer: recent developments, current trends and future directions

Gastro-esophageal adenocarcinomas (GEA) represent a severe global health burden and despite improvements in the multimodality treatment of these malignancies the prognosis of patients remains poor. HER2 overexpression/amplification has been the first predictive biomarker approved in clinical practice to guide patient selection for targeted treatment with trastuzumab in advanced gastric and gastro-esophageal junction cancers. More recently, immunotherapy has been approved for the treatment of GEA and PD-L1 expression is now a biomarker required for the administration of pembrolizumab in these diseases. Significant progress has been made in recent years in dissecting the genomic makeup of GEA in order to identify distinct molecular subtypes linked to distinct patterns of molecular alterations. GEA have been found to be highly heterogeneous malignances, representing a challenge for biomarkers discovery and targeted treatment development. The current review focuses on an overview of established and novel promising biomarkers in GEA, covering recent molecular classifications from TCGA and ACRG. Main elements of molecular heterogeneity are discussed, as well as emerging mechanisms of primary and secondary resistance to HER2 targeted treatment and recent biomarker-driven trials. Future perspectives on the role of epigenetics, miRNA/lncRNA and liquid biopsy, and patient-derived xenograft models as a new platform for molecular-targeted drug discovery in GEA are presented. Our knowledge on the genomic landscape of GEA continues to evolve, uncovering the high heterogeneity and deep complexity of these tumors. The availability of new technologies and the identification of promising novel biomarker will be critical to optimize targeted treatment development in a setting where therapeutic options are currently lacking. Nevertheless, clinical validation of novel biomarkers and treatment strategies still represents an issue.

HER2 is frequently overexpressed in hepatoid adenocarcinoma and gastric carcinoma with enteroblastic differentiation: a comparison of 35 cases to 334 gastric carcinomas of other histological types

AIMS

α-Fetoprotein (AFP)-producing gastric carcinoma (AFPGC) is one of the most aggressive GC subtypes. Frequent expression of human epidermal growth factor receptor 2 (HER2) has previously been reported in hepatoid adenocarcinoma (HAC), a major histological subtype of AFPGC originating from common-type GC (CGC). However, HER2 expression levels in other AFPGC histological subtypes are unknown. In this study, we analysed HER2 expression in GCs with primitive phenotypes in addition to HAC.

METHODS

HER2 expression was evaluated in representative complete sections from 16 HACs, 19 GCs with enteroblastic differentiation (GCEDs) and 334 GCs of other histological types as controls. The Ruschoff/Hofmann method was used to score HER2 immunohistochemistry. Samples with a HER2 score of 2+ were further assessed using fluorescence in situ hybridisation. Oncofetal protein (OFP) expression in HAC and GCED was tested via immunohistochemical staining for AFP, glypican 3 and Sal-like protein 4.

RESULTS

Thirty of 35 HAC/GCED cases comprised more than two histological patterns. The HER2 positivity rates of each histological component in the HACs/GCEDs were 25.0% for HAC (n=16), 34.6% for GCED (n=26) and 48.1% for CGC (n=27), which were higher than those of the control group (13.8%). Additionally, the majority of CGC components in HACs/GCEDs were positive for OFP (88.9%).

CONCLUSIONS

HER2 is frequently overexpressed not only in HAC but also in GCED and CGC components of HACs/GCEDs, which suggests an association between HER2 and OFP expression. Moreover, our findings suggest that HER2-positive CGC has a higher risk of progression to HAC/GCED than HER2-negative GC.