Comparative study on overexpression of HER2/neu and HER3 in gastric cancer

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

INTRODUCTION

The mysteries of complex molecular pathways of tumorigenesis are only beginning to be unraveled. Overexpression of HER2 receptors has been associated with adverse outcomes in certain malignant solid tumors.

AREAS COVERED

The authors give a focused review of the HER2 pathway and its importance for cancer cell survival. Similar to the situation in breast cancer, HER2 overexpression is seen in up to one-quarter of all gastric and gastroesophageal junction adenocarcinomas. The audience will also be familiarized with the existing HER2 targeted agents (both at the bench and at the bedside) for the therapy of gastric and gastroesophageal cancers.

EXPERT OPINION

Despite recent advances, treatment of upper gastrointestinal malignancies remains a significant challenge. Trastuzumab in combination with chemotherapy is the current standard of therapy for patients with metastatic HER2-overexpressing esophageal and gastric cancers. The activity of lapatinib, an active agent in advanced HER2-positive breast cancer, is now being tested in HER2-overexpressing esophageal and gastric adenocarcinomas. A variety of monoclonal antibodies and tyrosine kinase inhibitors with affinity for HER2 are in development and may improve further the outcomes of these malignancies.

How will human epidermal growth factor receptor 2-neu data impact clinical management of gastric cancer?

PURPOSE OF REVIEW

Human epidermal growth factor receptor 2 (HER2) amplification and overexpression play a central role in initiation, progression and metastasis of some common cancers, including breast and gastric cancer. About 20% of gastric and esophagogastric junction (EGJ) tumors overexpress HER2, providing a rationale to investigate trastuzumab, a monoclonal antibody directed against HER2, in this setting. This review focuses on the current role of HER2 inhibition as a new treatment option for gastric and EGJ cancer and discusses the optimization of gastric cancer-specific HER2 testing and analysis.

RECENT FINDINGS

In the phase III ToGA trial, the addition of trastuzumab to chemotherapy significantly improved overall survival without compromising safety in patients with HER2-positive metastatic gastric or EGJ cancer. This improvement was mainly the result of the survival advantage conferred to patients with high expression of the HER2 protein, defined as immunohistochemistry (IHC) 3+ or IHC 2+/fluorescent in-situ hybridization (FISH) +.

SUMMARY

On the basis of the results of the ToGA trial, HER2 status should now be included in the diagnostic workup of patients presenting with advanced gastric and EGJ cancer. The addition of trastuzumab to chemotherapy is a new standard treatment for patients with locally advanced and irresectable, recurrent or metastatic HER2-positive disease.

Fluorescence in situ hybridization versus immunohistochemistry in the detection of Her-2 gene amplification and protein expression in gastric cancer

AIM: To compare the difference and correlation between immunohistochemistry (IHC) to detect Her-2 protein expression and fluorescent in situ hybridization (FISH) to detect Her-2 gene amplification in gastric cancer and to assess their clinical value.

METHODS: Immunohistochemistry and FISH were used to detect Her-2 protein expression and Her-2 gene amplification in 118 cases of gastric carcinoma, respectively. A comparative analysis was then performed.

RESULTS: Of 118 cases of gastric carcinoma, 40 showed no Her-2 protein expression (0), 33 showed mild expression (+), 16 had moderate expression (++), and 29 had strong expression (+++). The rate of Her-2 protein overexpression was 24.6%. Her-2 gene amplification was detected in 38 cases, and 80 cases had no amplification. The rate of Her-2 gene amplification was 32.2%. Of 40 cases of gastric carcinoma showing no Her-2 protein expression, 38 (95%) had no Her-2 gene amplification (95%). Of 33 patients showing Her-2 protein mild expression, 30 (90.9%) had no Her-2 gene amplification. Of 16 patients showing moderate Her-2 protein expression, 9 had no gene amplification. Of 29 patients showing strong Her-2 protein expression, 26 (89.7%) had Her-2 gene amplification.

CONCLUSION: The total coincidence rate between IHC and FISH was 85.6%. IHC can be used for initial screening of Her-2 expression status in gastric cancer. When moderate or strong Her-2 protein expression is detected, it is necessary to conduct FISH assay to confirm the result.

Phase II trial of modified FOLFOX6 and erlotinib in patients with metastatic or advanced adenocarcinoma of the oesophagus and gastro-oesophageal junction

BACKGROUND

There is increased recognition that cancers of the upper GI tract comprise distinct epidemiological and molecular entities. Erlotinib has shown activity in patients with adenocarcinoma of the oesophagus/gastro-oesophageal junction (GEJ), but not in distal gastric cancer. mFOLFOX6 is one of several active regimens used to treat adenocarcinoma of the Eso/GEJ. This study evaluates the efficacy and safety of mFOLFOX6 and erlotinib in patients with metastatic or advanced Eso/GEJ cancers.

METHODS

Patients with previously untreated advanced or metastatic Eso/GEJ adenocarcinoma are treated with oxaliplatin 85 mg m(-2), 5-FU 400 mg m(-2), LV 400 mg m(-2) on day 1, 5-FU 2400 mg m(-2) over 48 h and erlotinib 150 mg PO daily. Treatment was repeated every 14 days. The primary objective was response rate (RR), secondary objectives include toxicity, progression-free survival (PFS), overall survival (OS) and to correlate clinical outcome with expression patterns and molecular alterations in the epidermal growth factor receptor-dependent pathways.

RESULTS

A total of 33 patients were treated and evaluable: there were two complete responses, 15 partial responses for an objective RR of 51.5% (95% CI, 34.5-68.6%). Median PFS was 5.5 months (95% CI, 3.1-7.5 months) and median OS was 11.0 months (95% CI, 8.0-17.4 months). The most common grade 3-4 toxicities were: diarrhoea (24%), nausea/vomiting (11%), skin rash (8%) and peripheral neuropathy (8%). The frequency of alterations was KRAS mutations (8%), EGFR mutations (0%) and HER2 amplification (19%).

CONCLUSION

In patients with Eso/GEJ adenocarcinoma, mFOLFOX6 and erlotinib is active, has an acceptable toxicity profile and FOLFOX ± erlotinib could be considered for further development.

Her-2/neu gene amplification and over-expression in stomach and esophageal adenocarcinoma: from pathology to treatment

Discovery of the over-expression of Her-2/neu or the amplification of its regulatory gene in stomach and esophageal cancer has resulted in targeted treatment directed at this protein. The fact itself and its consequences have been the topic of an abundance of studies and clinical trials. In the present report we review the current state of the art as regards diagnosis of the over-expression and amplification of Her-2/neu, its inhibition as a new therapeutic concept, treatment toxicity, and the development of resistance to Her-2/neu as a limiting factor in stomach and esophageal adenocarcinoma.

Prognostic significance of HER2/neu expression in gastric cancer

BACKGROUND

Gastric cancer is still the most prevalent neoplasia in many countries. Therefore, besides the clinicopathological factors known to be prognostic markers, new independent parameters are being investigated. There is mounting evidence of the role of HER2/neu expression in patients with this type of cancer, and it has been solidly correlated to poor outcomes and a more aggressive disease.

PATIENTS AND METHODS

Fifty gastric cancer tissue specimens were examined for the presence of HER2/neu by immunohistochemistry. The correlation between HER2/neu expression and patient clinicopathological parameters was evaluated and the prognostic significance of HER2/neu expression was assessed.

RESULTS

HER2/neu membrane staining was detectable in 7 (14.0%) cases. The patients with HER2/neu overexpression had worse prognosis after surgical therapy compared with those without expression of HER2/neu (p = 0.001, Log-rank test). No relationship was found between HER2/neu expression and other clinicopathological parameters.

CONCLUSIONS

Using immunohistochemistry, our data showed that the association between HER2/neu overexpression and patient survival provides a good indirect validation for quality of this investigation and it may act as a prognostic parameter in gastric cancer.

[HER2 and gastric cancer. Recommendations for clinical practice in 2011]

Trastuzumab in combination with capecitabine or 5-fluorouracil and cisplatin has been approved by the European Medicines Agency (EMEA) for the treatment of patients with human epidermal growth factor receptor 2 (HER2)-positive (immunohistochemistry [IHC] 3+ or IHC 2+/ fluorescence in situ hybridization [FISH]-positive or IHC 2+/ silver in situ hybridization [SISH]-positive) metastatic adenocarcinoma of the stomach or gastro-esophageal (GE) junction. HER2 testing in gastric cancer (GC) differs from testing in breast cancer (BC) due to major differences in the tumor biology; as the disease is progressing rapidely, we recommend to test every GC at diagnosis and to offer a rapid testing (less than five days) in the metastatic setting. IHC should be the initial testing methodology and FISH or SISH should be used to retest IHC 2+ samples. As GC more frequently shows incomplete membrane staining and focal staining for HER2, HER2 testing guidelines have been adapted from BC protocols. The scoring system is slightly different in respect to the characteristics of GC. For in situ hybridization, SISH should be used in order to identify heterogeneous staining with a higher accuracy than FISH. Enrollment in training and quality assurance programs is highly recommended. In case of negativity on biopsy, it is recommended to retest for HER2, when possible, on surgical specimens and/or metastasis. This will ensure accurate and consistent HER2 testing results, which will allow the appropriate selection of patients eligible for treatment with trastuzumab.

New developments in the treatment of metastatic gastric cancer: focus on trastuzumab

Patients with metastatic gastric cancer have a poor outcome. The development of new combinations of chemotherapy has led to steady but only modest gains in overall survival with largest effects reported with two- and three-drug regimens. Trastuzumab, a fully humanized monoclonal antibody directed at the human epidermal growth factor receptor-2 (HER2), has been found to improve response rate and survival in patients with advanced gastric cancer. This update will review the role of HER2 and summarize therapeutic advances in the use of trastuzumab in advanced gastric cancer.

Interaction between adipose tissue stromal cells and gastric cancer cells in vitro

Adipose tissue exists in the gastric submucosa and subserosa. Thus, adipose tissue stromal cells (ATSCs), which include mesenchymal stem cells (MSCs), seem critical for the progression of gastric cancer but their interaction with the cancer cells is unknown. We demonstrated an interaction between these cells, using immunohistochemistry, Western blot and the collagen gel invasion assay system, in which the adenocarcinoma cells (well and poorly differentiated types, MKN28 and MKN45, respectively) were cultured on a ATSC-embedded or ATSC-non-embedded gel. ATSCs promoted the expression of the growth marker, proliferation cell nuclear antigen but inhibited that of the apoptosis marker, single-stranded DNA, in the cancer cell types. ATSCs accelerated the invasion of only MKN28 into the gel and promoted the expression of mitogen-activated protein kinase (MAPK, pERK-1/2) but decreased that of the molecularly targeted protein, HER2, in the cancer cells. ATSCs did not affect the expression of the prostaglandin biosynthetic enzyme cyclooxgenase-2 (COX-2) in the cancer cells. The COX-2 inhibitor celecoxib did not affect the morphology or invasion of the cancer cells. The cancer cell types in turn promoted the display of the myofibroblast marker, α-smooth muscle actin, whereas they decreased that of some MSC markers, e.g., CD44 and CD105, in ATSCs. The data suggest that (1) ATSCs influence the progression of gastric cancer by increasing their growth/invasion and decreasing their apoptosis through MAPK activation in a COX-2-independent way; (2) ATSCs adversely affect HER2-targeted therapy; (3) the cancer cells induce the cancer-associated myofibroblast phenotype in ATSCs.

Genomic and genetic alterations influence the progression of gastric cancer

Gastric cancer is one of the leading causes of cancer-related deaths worldwide, although the incidence has gradually decreased in many Western countries. Two main gastric cancer histotypes, intestinal and diffuse, are recognised. Although most of the described genetic alterations have been observed in both types, different genetic pathways have been hypothesized. Genetic and epigenetic events, including 1q loss of heterozygosity (LOH), microsatellite instability and hypermethylation, have mostly been reported in intestinal-type gastric carcinoma and its precursor lesions, whereas 17p LOH, mutation or loss of E-cadherin are more often implicated in the development of diffuse-type gastric cancer. In this review, we summarize the sometimes contradictory findings regarding those markers which influence the progression of gastric adenocarcinoma.

Human epidermal growth factor receptor 2 (HER2) in gastric cancer: a new therapeutic target

Surgery is the only curative therapy for gastric cancer. In the metastatic setting the objective of treatment is to manage symptoms, improve quality of life and prolong survival, but current treatment options have limited efficacy and some of them exhibit unfavourable toxicity profiles. Fluoropyrimidine, taxanes and platinum-based regimens are used most frequently and offer a response rate of 30-50% with a median overall survival of =1 year. These discouraging data support the need for new therapeutic strategies based on targeted drugs. Trastuzumab, a monoclonal antibody against HER2, has shown survival benefits when given with chemotherapy in all setting of HER2-positive breast cancer patients. The ToGA trial, the first study evaluating the efficacy and safety of adding trastuzumab to chemotherapy in HER-2 positive advanced gastric cancer, showed a significant superiority of combination over chemotherapy alone. Based on these results trastuzumab combined with a cisplatin and fluoropyrimidine regimen appear the new reference treatment for HER-2 positive metastatic gastric cancer.

Capecitabine in Combination with Oxaliplatin as First-Line Therapy for Advanced Gastric Cancer: A Case Report

Gastric cancer is one of the most common cancers worldwilde. The five-year survival for stage IV gastric cancer is around 5–10% in Western countries. Advanced gastric cancer is sensitive to numerous agents, but there is no generally accepted standard regimen. Here we report on a case of advanced gastric cancer occurring in a 72-year-old man who underwent treatment with capecitabine plus oxaliplatin, achieving a complete response. Free full text available at www.tumorionline.it

Lack of HER2 overexpression and amplification in small intestinal adenocarcinoma

HER2 overexpression and amplification have been studied as a therapeutic and prognostic target in a number of human cancers, including esophageal, gastric, and colorectal adenocarcinomas. However, HER2 status has not been well investigated in primary small intestinal adenocarcinoma, probably because of its rarity. In this study, we conducted immunohistochemical analysis and fluorescence in situ hybridization (FISH) for HER2 on 49 primary nonampullar small intestinal adenocarcinomas. The results showed a complete lack of HER2 protein expression in 47 cases (96%) by immunohistochemical analysis. Only 2 cases (4%) showed a 1+ staining pattern. No tumors exhibited 2+ or 3+ HER2 immunoreactivity. By FISH, none of the tumors, including those with 1+ HER2 immunoreactivity, exhibited HER2 gene amplification. These observations demonstrate that HER2 protein overexpression and gene amplification are infrequent events, if they occur at all, in small intestinal adenocarcinoma. Thus, routine immunohistochemical and/or FISH testing for HER2 for potential targeted anti-HER2 therapy may not be beneficial for patients with primary small intestinal adenocarcinoma.

Clinical aspects of gastric cancer and Helicobacter pylori--screening, prevention, and treatment

Gastric cancer still represents a global health care burden, and in the absence of strategies implemented for early detection, the disease continues to have a dismal prognosis. Patients presenting with clinical manifestations of gastric cancer have limited options for cure. Thus, early detection and prevention play a key role in the fight against gastric cancer. Serologic-based test methods have the potential to detect a subset of patients at high risk of gastric cancer that require a close clinical and endoscopic follow-up. More data have been produced to support Helicobacter pylori eradication as an efficient strategy to prevent gastric cancer. Treatment options for patients with an advanced disease are still limited, but the introduction of new agents opens a more optimistic perspective for the future.

HER2 diagnostics in gastric cancer-guideline validation and development of standardized immunohistochemical testing

Trastuzumab-based therapy has been shown to confer overall survival benefit in HER2-positive patients with advanced gastric cancer in a large multicentric trial (ToGA study). Subgroup analysis identified adenocarcinomas of the stomach and gastroesophageal (GE) junction with overexpression of HER2 according to immunohistochemistry (IHC) as potential responders. Due to recent approval of trastuzumab for HER2 positive metastatic gastric and GE-junction cancer in Europe (EMEA) HER2 diagnostics is now mandatory with IHC being the primary test followed by fluorescence in situ hybridization (FISH) in IHC2+ cases. However, in order to not miss patients potentially responding to targeted therapy determination of a HER2-positive status for gastric cancer required modification of scoring as had been proposed in a pre-ToGA study. To validate this new HER2 status testing procedure in terms of inter-laboratory and inter-observer consensus for IHC scoring a series of 547 gastric cancer tissue samples on a tissue microarray (TMA) was used. In the first step, 30 representative cores were used to identify specific IHC HER2 scoring issues among eight French and German laboratories, while in the second step the full set of 547 cores was used to determine IHC HER2 intensity and area score concordance between six German pathologists. Specific issues relating to discordance were identified and recommendations formulated which proved to be effective to reliably determine HER2 status in a prospective test series of 447 diagnostic gastric cancer specimens.

Clinical significance of Her-2 protein expression in gastric cancer

AIM: To investigate the correlation between Her-2 protein expression and clinicopathological characteristics of gastric carcinoma.

METHODS: Her-2 protein expression was examined by immunohistochemistry (EliVisionTM plus) in 778 gastric adenocarcinoma specimens.

RESULTS: The positive rate of Her-2 protein overexpression (+++) was 11.35% (68/576). Her-2 protein overexpression was associated with tumor histotype, differentiation, TNM stage, and distant metastasis (all P < 0.05), but not with sex, age, tumor site, and lymph node metastasis (all P > 0.05). Multivariate analysis demonstrated that tumor histotype, differentiation, TNM stage, and distant metastasis were significant predictors of Her-2 protein overexpression in gastric carcinoma (all P > 0.05). Moderate Her-2 protein expression (++) was detected in 5.68% of gastric carcinoma specimens.

CONCLUSION: Detection of Her-2 protein expression may be used to assess the malignant biological behavior and prognosis of gastric cancer. Gastric cancer patients exhibiting Her-2 protein overexpression might constitute potential candidates for new adjuvant therapies that involve the use of humanized monoclonal antibodies.

HER3 comes of age: new insights into its functions and role in signaling, tumor biology, and cancer therapy

The human epidermal growth family (HER) of tyrosine kinase receptors underlies the pathogenesis of many types of human cancer. The oncogenic functions of three of the HER proteins can be unleashed through amplification, overexpression, or mutational activation. This has formed the basis for the development of clinically active targeted therapies. However, the third member HER3 is catalytically inactive, not found to be mutated or amplified in cancers, and its role and functions have remained shrouded in mystery. Recent evidence derived primarily from experimental models now seems to implicate HER3 in the pathogenesis of several types of cancer. Furthermore, the failure to recognize the central role of HER3 seems to underlie resistance to epidermal growth factor receptor (EGFR)- or HER2-targeted therapies in some cancers. Structural and biochemical studies have now greatly enhanced our understanding of signaling in the HER family and revealed the previously unrecognized activating functions embodied in the catalytically impaired kinase domain of HER3. This renewed interest and mechanistic basis has fueled the development of new classes of HER3-targeting agents for cancer therapy. However, identifying HER3-dependent tumors presents a formidable challenge and the success of HER3-targeting approaches depends entirely on the development and power of predictive tools.