Overexpression of c-ErbB-2 protein in gastric cancer by immunohistochemical stain

Human epidermal growth factor 2 overexpressed alpha-fetoprotein-producing-gastric cancer

PURPOSE

This study aimed to elucidate the clinicopathological characteristics of α-fetoprotein (AFP)-producing gastric carcinoma (AFP-GC) with human epidermal growth factor receptor (HER)2 overexpression to extend the treatment strategy for AFP-GC.

METHODS

We analyzed 41 patients with AFP-GC who underwent surgical resection or chemotherapy from 1989 to 2019, and who had over 20ng/mL of serum AFP or positive immunohistochemical AFP expression. HER2 expression status was investigated by immunohistochemistry (IHC) for all patients and by fluorescence in situ hybridization (FISH) for cases with an IHC score of 2+. AFP-GC with an IHC score of 3 + or 2 + and FISH positivity was defined as HER2 overexpressed AFP-GC. The correlation between HER2 status and clinicopathological characteristics and prognosis in AFP-GC was analyzed.

RESULTS

HER2 overexpression was detected in 17.1% of AFP-GC patients. The prognosis of the patients with HER2 overexpressed AFP-GC was not significantly different compared to HER2 non-overexpressed AFP-GC. HER2 overexpressed AFP-GC consisted of heterogeneous histology with a higher proportion of mixed-type tumors (p = 0.002). The clinical outcome of AFP-GC with mixed-type of histology tended to be better than other intestinal or diffuse types (p = 0.05).

CONCLUSION

HER2 overexpressed AFP-GC consisted of a mixed type of histology, which showed a better prognosis. The results presented that HER2 status in AFP-GC is one of the molecular candidates to improve the prognosis.

C-erbB-2 Oncoprotein in Gastric Carcinoma: Correlation with Clinical Stage and Prognosis

The aim of this study was to investigate the expression of the oncogene c-erbB-2 in gastric tumors. Immunohistochemical study of the expression of c-erbB-2 was performed in formalin-fixed, paraffin-embedded sections from 82 gastric adenocarcinomas using polyclonal antibody. c-erbB-2-positive immunostaining was observed in 37 (45%) tumors. Positive staining was detected in 63% of well differentiated, 46% of moderately differentiated and 80% of papillary adenocarcinomas. In poorly differentiated adenocarcinomas, positivity for c-erbB-2 was observed in 21%. According to the Lauren classification, a higher frequency of c-erbB-2 positive staining was observed in intestinal type tumors (70%). During the follow-up period 43% of the patients with c-erbB-2 oncoprotein-negative tumors and 45% of the patients with c-erbB-2 oncoprotein-positive tumors died. There was no significant association between c-erbB-2 staining and sex, age, clinical stage, tumor grade, histological type or survival rates. In conclusion, almost half of the gastric cancers were positive for c-erbB-2. Nonetheless, the expression of c-erbB-2 oncoprotein did not play a role in prognosis.

Impact of c-erbB-2 protein on 5-year survival rate of gastric cancer patients after surgery: a cohort study and meta-analysis

OBJECTIVE

To explore the association of c-erbB-2 protein expression with clinicopathological characteristics and prognosis of gastric cancer (GC) after surgery.

METHODS

A total of 133 patients undergoing surgical resection for GC between March 2006 and January 2009 in the Second Affiliated Hospital of Wenzhou Medical University were included in this study. c-erbB-2 protein expression was determined by immunohistochemistry. Afterwards, a meta-analysis was performed to further confirm the association between c-erbB-2 protein expression and GC by employing stringent inclusion and exclusion criteria. All data analyses were conducted with STATA 12.0 and SPSS 19.0.

RESULTS

There was no significant difference in c-erbB-2 expression among patients with various parameters including age, gender and histological types (all p>0.05). Among 133 GC patients, 32 patients presented c-erbB-2-positive expression and 101 presented c-erbB-2-negative expression (24.1% vs. 75.9%). The c-erbB-2-positive expression rate was significantly higher in GC tissues of patients with lymph node metastasis than those without. Similarly, a significant increase in c-erbB-2 expression was observed in well/moderately differentiated GC tissues compared with poorly differentiated GC. Patients with negative c-erbB-2 expression had a higher 5-year survival rate than those with positive c-erbB-2 expression, which was consistent with the results of the meta-analysis (OR = 0.54, 95% CI 0.37-0.80, p = 0.002).

CONCLUSIONS

Our study demonstrated that high expression of c-erbB-2 protein was strongly associated with lymph node metastasis, histological differentiation and 5-year survival rate in GC patients after surgery.

Clinical Significance of HER2 Overexpression in Gastric and Gastroesophageal Junction Cancers

BACKGROUND

In this study, we investigated the rate of human epidermal growth factor receptor 2 (HER2) overexpression in gastric (GC) and gastroesophageal junction cancers (GEJCs) and the relationship with HER2 expression and clinical, pathological parameters and prognosis.

METHODS

Surgery or biopsy specimen of 598 (436 males, 162 females) patients with GC or GEJC was evaluated for the presence of HER2 overexpression by immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) methods.

RESULTS

HER2 IHC scores were as follows: 418 (69.9%) IHC 0, 58 (9.7%) IHC 1+, 50 (8.4%) IHC 2+, 72 (12%) IHC 3+. Among 50 patients with IHC 2+, 18 (38.2%) were FISH positive, and 29 (61.7%) were FISH negative for HER2 amplification. Patients were regarded as HER2 positive in case of IHC 3+ disease or IHC 2+ disease with a positive FISH test result for HER2 amplification. In the primary analysis population, 90 (15%) were considered HER2 positive. HER2 positivity was higher in intestinal GC compared to diffuse GC (16.9 vs 6.6%, p = 0.014). HER2 positivity was significantly higher in well and moderately differentiated tumors than poorly differentiated tumors (p < 0.0001). HER2 positivity had no significant effect on median OS (23.2 vs 19.1 months, p = 0.44). But in the early stages (stages I and II), median OS of HER2-positive patients was shorter than HER2-negative patients (51.4 months vs not reach, p = 0.047). However, median OS was similar in patients with advanced stages (stages III and IV) HER2-positive and HER2-negative disease (16.2 vs 13.7 months, p = 0.72).

CONCLUSIONS

Rate of HER2 positivity is similar in Turkish patients with GC and GEJCs. HER2 positivity is associated with poor prognosis in patients with early-stage disease.

HER-2 incidence in gastric cancer, its association with prognosis and clinicopathological parameters

OBJECTIVE

Human epidermal growth factor-2 (HER-2) overexpression has prognostic value in breast cancer. However, the significance of HER-2 positivity in gastric cancer is controversial. In this study, we investigated the frequency of overexpression of HER-2 and its relationship with clinicopathological findings and impact on survival in gastric cancer.

MATERIAL AND METHODS

Gastric cancer patients, operated in Marmara University Faculty of Medicine, Pendik Training and Research Hospital, General Surgery Department, between January 2012-December 2013 were enrolled in this study. Medical records were retrospectively evaluated. Tissue samples were stained by immunohistochemistry (IHC) method, and were followed by fluorescence in situ hybridization (FISH) in those with positive results. HER-2 expression rates and its association with other histopathological features and survival have been analyzed.

RESULTS

135 patients were enrolled in the study, with 88 (65%) male and 47 (35%) female patients. The median age was 61 (29-84) years. Only 11 patients (8%) were positive for HER-2. HER-2 positive patients were similar to negative patients in terms of age, gender, tumor size, tumor location, tumor T stage, lymph node metastasis, histological type, differentiation, lymphovascular invasion, perinodal, perineural invasion and stage. No significant difference was detected on 1 and 2-year overall and disease-free survival rates between receptor positive and negative groups.

CONCLUSION

Consistent with the literature data, HER-2 positivity rate in this study was approximately 8%, but this positivity has not been found to be associated with either clinical and pathological parameters or overall and disease-free survival.

Correlations of Human Epithelial Growth Factor Receptor 2 Overexpression with MUC2, MUC5AC, MUC6, p53, and Clinicopathological Characteristics in Gastric Cancer Patients with Curative Resection

Background. The purpose of this study was to evaluate the relationships between HER2 overexpression in the tumor and MUC2, MUC5AC, MUC6, and p53 status and clinicopathological characteristics of gastric cancer patients. Methods. This retrospective study included 282 consecutive patients with gastric cancer who underwent surgery at the Kosin University Gospel Hospital between April 2011 and December 2012. All tumor samples were examined for HER2 expression by immunohistochemistry (IHC) and MUC2, MUC5AC, MUC6, and p53 expression by staining. A retrospective review of the medical records was conducted to determine the correlation between the presence of HER2 overexpression and clinicopathological factors. Results. The HER2-positive rate was 18.1%. Although no association was found between HER2 expression and MUC5AC, the expression of MUC2, MUC6, and p53 was significantly correlated with HER2 positivity, respectively (P = 0.004, 0.037, 0.002). Multivariate analysis revealed that HER2 overexpression and nodal status were independent prognostic factors. Conclusions. HER2 overexpression in gastric carcinoma is an independent poor prognostic factor.

EGFR, HER-2 and KRAS in canine gastric epithelial tumors: a potential human model?

Epidermal growth factor receptor (EGFR or HER-1) and its analog c-erbB-2 (HER-2) are protein tyrosine kinases correlated with prognosis and response to therapy in a variety of human cancers. KRAS mediates the transduction of signals between EGFR and the nucleus, and its mutation has been identified as a predictor of resistance to anti-EGFR drugs. In human oncology, the importance of the EGFR/HER-2/KRAS signalling pathway in gastric cancer is well established, and HER-2 testing is required before initiating therapy. Conversely, this pathway has never been investigated in canine gastric tumours. A total of 19 canine gastric epithelial neoplasms (5 adenomas and 14 carcinomas) were retrospectively evaluated for EGFR/HER-2 immunohistochemical expression and KRAS mutational status. Five (35.7%) carcinomas were classified as intestinal-type and 9 (64.3%) as diffuse-type. EGFR was overexpressed (≥1+) in 8 (42.1%) cases and HER-2 (3+) in 11 (57.9%) cases, regardless of tumour location or biological behaviour. The percentage of EGFR-positive tumours was significantly higher in the intestinal-type (80%) than in the diffuse-type (11.1%, p = 0.023). KRAS gene was wild type in 18 cases, whereas one mucinous carcinoma harboured a point mutation at codon 12 (G12R). EGFR and HER-2 may be promising prognostic and therapeutic targets in canine gastric epithelial neoplasms. The potential presence of KRAS mutation should be taken into account as a possible mechanism of drug resistance. Further studies are necessary to evaluate the role of dog as a model for human gastric cancer.

Differing deregulation of HER2 in primary gastric cancer and synchronous related metastatic lymph nodes

BACKGROUND

The aim of this study was to investigate how differences in expression of HER2 between primary gastric cancers (PGCs) and their corresponding metastatic lymph nodes (LMNs) might affect its potential as a prognostic indicator in treatments including anti-HER2 agents.

METHODS

The analysis was conducted in 102 patients who underwent surgical resection for primary gastric cancers (PGCs; adenocarcinoma, intestinal type) with synchronous LNMs. HER2 gene status and protein expression were investigated by immunohistochemistry (IHC) in all patients; fluorescence in situ hybridization (FISH) was performed in 22 patients. The correlation between HER2 gene status in PGCs and their LNMs was evaluated.

RESULTS

Positive HER2 expression as detected by IHC + FISH was observed in 27/102 PGC samples (26.5%) and 29/102 LNM samples (28.4%). HER2 amplification status in 102 paired PGC and LNM samples as evaluated by FISH + IHC was concordant in 92 patients (90.2%), 69 (67.6%) were unamplified and 23/102 (22.5%) were amplified at both sites, and discordant in 10 patients (9.8%), 4 (3.9%) were positive for PGC and negative for LNM, while 6 (5.9%) were positive for LNM and negative for PGC. The results of FISH + IHC showed very strong concordance in HER2 status between the PGC and LNM groups (k = 0.754).

CONCLUSION

The high concordance between HER2 results for PGCs and their LNMs indicates that assessment of HER2 status in the primary cancer alone is a reliable basis for deciding treatment with anti-HER2 agents in patients with LNMs from gastric adenocarcinoma.

VIRTUAL SLIDES

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/9365749431029643.

Heterogeneity of ERBB2 in gastric carcinomas: a study of tissue microarray and matched primary and metastatic carcinomas

Trastuzumab in association with systemic cytotoxic chemotherapy is a therapeutic option for patients with advanced or metastatic ERBB2+ gastric carcinoma. The status of the ERBB2 overexpression or gene amplification is an important predictive marker in gastric cancer. However, it is controversial whether the primary tumor is representative of distant metastases in terms of ERBB2 status. Quadruplicated tissue microarrays from formalin-fixed paraffin-embedded tissues from 498 advanced primary gastric carcinomas and 97 matched metastatic lymph nodes were investigated by immunohistochemistry with HercepTest and silver in situ hybridization. For further comparison, another set of 41 paired primary and distant metastatic gastric carcinomas were also tested. Intratumoral heterogeneity was defined as different results between tissue microarray cores. ERBB2-positivity was observed in 52 gastric carcinomas (10%) and was not associated with recurrence of disease or survival of patients. In ERBB2-positive primary gastric carcinomas, heterogeneous ERBB2 overexpression was observed in 21/63 (33%) gastric carcinomas and heterogeneous ERBB2 gene amplification in 14/62 (23%) cases. Repeated immunohistochemistry and silver in situ hybridization in representative paraffin tumor blocks confirmed focal ERBB2 overexpression and ERBB2 gene amplification and did not change the final results. Discrepancies in ERBB2 results between primary and paired metastatic lymph nodes were observed in 11% of cases by immunohistochemistry and 7% by silver in situ hybridization. Out of the 41 paired primary and distant metastases, 5 (12%) cases were ERBB2-positive, and discrepancy was observed in one case. Intratumoral heterogeneity and discrepant ERBB2 results in primary and metastatic tumor are not uncommon in gastric carcinoma. Results of silver in situ hybridization showed less frequent heterogeneity compared with immunohistochemistry. Wherever possible, ERBB2 immunohistochemistry testing should be performed in both primary and distant metastatic sites.

Clinicopathologic features and treatment outcomes of patients with human epidermal growth factor receptor 2-positive adenocarcinoma of the esophagus and gastroesophageal junction

Human epidermal growth factor receptor 2 (HER2) is overexpressed in 21% of gastric and 33% of gastroesophageal junction (GEJ) adenocarcinomas. Trastuzumab has been approved for metastatic HER2-positive gastric/GEJ cancer in combination with chemotherapy. This retrospective analysis was undertaken to better define the clinicopathologic features, treatment outcomes, and prognosis in patients with HER2-positive adenocarcinoma of the esophagus/GEJ. Pathologic specimens from 156 patients with adenocarcinoma of the esophagus/GEJ treated on clinical trials with chemoradiation and surgery were tested for HER2. Seventy-six patients also received 2 years of gefitinib. Baseline characteristics and treatment outcomes of the HER2-positive and negative patients were compared both in aggregate and separately for each of the two trials. Of 156 patients, 135 had sufficient pathologic material available for HER2 assessment. HER2 positivity was found in 23%; 28% with GEJ primaries and 15% with esophageal primaries (P= 0.10). There was no statistical difference in clinicopathologic features between HER2-positive and negative patients except HER2-negative tumors were more likely to be poorly differentiated (P < 0.001). Locoregional recurrence, distant metastatic recurrence, any recurrence, and overall survival were also statistically similar between the HER2-positive and the HER2-negative groups, in both the entire cohort and in the gefitinib-treated subset. Except for tumor differentiation, HER2-positive and negative patients with adenocarcinoma of the esophagus and GEJ do not differ in clinicopathologic characteristics and treatment outcomes. Given the demonstrated benefit of trastuzumab in HER2-positive gastric cancer and the similar incidence of HER2 overexpression in esophageal/GEJ adenocarcinoma, further evaluation of HER2-directed therapy in this disease seems indicated.

A large cohort of consecutive patients confirmed frequent HER2 positivity in gastric carcinomas with advanced stages

BACKGROUND

Trastuzumab in association with systemic cytotoxic chemotherapy is the standard of care for patients with advanced HER2-positive gastric carcinoma (GC). However, HER2 as a prognostic factor in GC remains controversial.

METHODS

HER2 overexpression and amplification was evaluated by immunohistochemistry (IHC) and silver in situ hybridization (SISH) in 2,798 GCs obtained from 2,727 gastrectomy and 71 open/laparoscopic biopsy specimens from patients with peritoneal seeding. Regional heterogeneity was defined as the proportion of tumor cells showing membranous staining in 10-70 % of tumor cells. Genetic heterogeneity was determined by the existence of HER2/CEP17 ratio higher than 2.0 in >5 to <50 % of tumor cells.

RESULTS

In IHC, 184 cases (6.6 %) were 3+ and 44 cases (1.6 %) were 2+. Of 44 HER2 2+ cases, SISH showed HER2 gene amplification in 21 cases (47.7 %), chromosome 17 polysomy in six cases (13.6 %), and genetic heterogeneity in five cases (11.4 %). HER2 positivity found in 7.3 % of GCs was significantly associated with older age, male gender, intestinal histology, upper third in location, higher lymph node stage (p < .002), and advanced AJCC stage (p = .033). Regional heterogeneity of HER2 was closely associated with 2+ (70.5 vs 42.9 % in 3+, p = .001) and diffuse or mixed histologic type (p = .005).

CONCLUSIONS

Regional heterogeneity of HER2 expression was closely associated with weak HER2 overexpression (2+) and with diffuse or mixed histology. Polysomy of chromosome 17 would be an important cause of HER2 2+ in IHC. Frequent HER2 positivity observed in GCs with advanced stages suggests that HER2 may be involved in tumor progression and poor prognosis.

Comparison of four immunohistochemical tests and FISH for measuring HER2 expression in gastric carcinomas

AIM

: Accurate testing for HER2 is essential to identify patients who are likely to benefit from trastuzumab therapy. Although comparative studies on the performance of commercially available immunohistochemistry (IHC) antibodies for HER2 have been performed in breast cancer, similar studies have not been done in gastric carcinoma (GC) thus far.

METHODS

: Quadruplicate tissue microarrays (TMAs) of 289 advanced GCs were immunostained with HercepTest, A0485, 4B5 and CB11, and the results were compared to those of gene amplification by fluorescence in situ hybridisation (FISH).

RESULTS

: HER2 was amplified by FISH in 38 (13.2%) GCs. HER2 overexpression (2+ or 3+) was observed in 40 (13.8%) cases by HercepTest, 46 (15.9%) by A0485, 40 (13.8%) by 4B5 and 27 (9.3%) by CB11. The sensitivity and specificity of IHC compared to FISH was 78.9%/96% for HercepTest, 86.5%/94.4% for A0485, 76.3%/95.6% for 4B5 and 60.5%/98.4% for CB11. Focal HER2 gene amplification was more common in GCs with no (0 and 1+) or low (2+) HER2 expression. Discordant IHC results were seen in 23 cases (8.0%) with the four antibodies. All HER2 3+ cases (n = 22) by HercepTest were positive with A0485 and 4B5, while one was negative with CB11. CB11 was found to be negative in 10 HercepTest 2+ and FISH+ cases.

CONCLUSION

: Focal HER2 gene amplification is more common in GCs with no or low expression of HER2. Although the specificity and positive predictive value of CB11 for FISH is highest, it lacks sufficient sensitivity to be used as a first line screening test to assess HER2 status in GCs.

HER2 as a Prognostic Marker in Gastric Cancer - A Systematic Analysis of Data from the Literature

Through the recent conduct of the ToGA trial, HER2 has shown to be predictive for the treatment with trastuzumab in advanced gastric and gastro-oesophageal cancer. When it comes to the prognostic properties the situation is different. Despite the fact that it is more than 20 years ago since the first studies demonstrating an association between a positive HER2 status and poor prognosis were published the issue is still controversial. In this current systematic review a large number of studies on HER2 and gastric cancer have been reviewed. The studies included in this review should fulfill the following two criteria. First criterion: The number of patients in each study should be ≥ 100, and the HER2 status should have been determined either by immunohistochemistry (IHC) or in situ hybridization (ISH). Second criterion: The selected articles should include an analysis of the association between the HER2 status and survival or relevant clinicopathological characteristics. Forty-two publications with a total of 12,749 patients fulfilled the two criteria and were reviewed in detail. The majority of the publications (71%) showed that a HER2-postive status measured either by IHC or ISH was associated with poor survival and/or clinicopathological characteristics, such as serosal invasion, lymph node metastases, disease stage, or distant metastases. Based on the current analysis a clear trend towards a potential role for HER2 as a negative prognostics factor in gastric cancer was shown, suggesting that HER2 overexpression and/or amplification is a molecular abnormality that might be linked to the development of 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.

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.

Trastuzumab in gastric cancer

Trastuzumab is a fully humanised monoclonal antibody directed at the human epidermal growth factor receptor-2 (HER-2) which has been a component of standard therapy for advanced and resected HER-2-positive breast cancers for almost a decade. HER-2 over-expression, defined as HER-2 protein over-expression using immunohistochemistry scored as 3+ and/or erbB-2 amplification detected by fluorescent in situ hybridisation, was detected in 22.1% of 3807 patients with advanced gastric and oesophagogastric junction (OGJ) adenocarcinoma screened for eligibility for the phase III ToGA study. The validated scoring system for HER-2 positivity in gastric cancers differs from that recommended for breast cancer due to an increased frequency of incomplete membranous immunoreactivity and heterogeneity of HER-2 expression in gastric cancers. The highest rates of HER-2 over-expression are observed in patients with OGJ rather than gastric tumours and intestinal-type rather than diffuse or mixed histology. The international multicentre randomised phase III ToGA study assessed the addition of trastuzumab to a cisplatin plus fluoropyrimidine (FP) chemotherapy doublet for patients with HER-2-positive advanced gastric or OGJ adenocarcinoma. The investigators reported a clinically and statistically significant benefit in terms of response rate (47.3% versus 34.5%, p=0.0017), median progression-free survival (6.7 versus 5.5 months, p=0.0002) and median overall survival (13.8 versus 11.1 months, p=0.0046). Trastuzumab plus FP chemotherapy is now the standard of care for patients with advanced gastric and OGJ cancers which over-express HER-2. Further research to evaluate trastuzumab delivered beyond progression, in combination with alternative first-line chemotherapy regimens, and in the perioperative and adjuvant setting is urgently needed. Additionally, research into mechanisms of resistance and strategies to overcome primary or acquired resistance to trastuzumab must now be expedited, using lessons learnt over the past decade in HER-2-positive breast cancer to maximise the benefit from this agent.

Growth inhibitory effects of trastuzumab and chemotherapeutic drugs in gastric cancer cell lines

The various treatments for advanced gastric cancer have limitations and induce only marginal survival benefit. HER-2/neu protein is overexpressed in several types of human cancers and its amplification is associated with poor prognosis. Recombinant humanized anti-HER-2/neu antibody (trastuzumab) not only inhibits the proliferation of HER-2/neu overexpressing tumor cells but also augments the cytotoxicity of concomitant chemotherapeutic agents in metastatic breast cancer. In this study, we evaluated the growth inhibitory effects of trastuzumab in gastric cancer cells. HER-2/neu protein was evaluated by immunohistochemical analysis in seven gastric cancer cell lines. MTT assay was performed to evaluate the growth inhibitory effects of trastuzumab and three chemotherapeutic agents, doxorubicin, cisplatin and paclitaxel, both alone and in combinations. The changes of cell cycle after trastuzumab treatment were analyzed by flow cytometry. Four of the cell lines, YCC-2 with strong positivity of HER-2/neu expression, NCI-N87 with moderate positivity, YCC-3 with weak positivity, and SK-BR-3 as a positive control, were selected. After in vitro MTT assay for 1-day and 5 consecutive days' treatment of trastuzumab at various concentrations, growth inhibition was not observed in any cancer cell lines. However, there was variable dose-dependent sensitivity to doxorubicin, cisplatin and paclitaxel. YCC-2 and SK-BR-3 cancer cells were more sensitive to three chemotherapeutic drugs, constantly (P<0.05). The combination of 5 consecutive days' treatment of trastuzumab with 1-day doxorubicin treatment showed significant growth inhibition only in YCC-2 and NCI-N87 gastric cancer cells. After 1-day trastuzumab treatment, the S-phase fraction was decreased by 52 and 70% in YCC-2 and SK-BR-3, respectively. In conclusion, the expressions of HER-2/neu protein in gastric cancer cells are variable, and concomitant treatments of trastuzumab with doxorubicin increase cytotoxicity. This suggests that trastuzumab-based biologic therapy with chemotherapeutic agents can be applied in gastric cancer treatment.

The expression of c-erbB-1 and c-erbB-2 in Iranian patients with gastric carcinoma

To assess the significance of epidermal growth factor receptor family members, the overexpression of c-erbB-1 and c-erbB-2 was retrospectively investigated in 146 southern Iranian gastric cancer patients. Indirect immunostaining was used to evaluate the expression of these two receptors in formalin-fixed paraffin-embedded tissue samples. c-ErbB-1 expression was observed in 47 (32.2%) and c-erbB-2 expression was observed in 24 (16.4%) of tumors. Significant positive correlations were observed between c-erbB-1 expression and tumor size, local invasion, lymph node involvement and tumor stage. There was also a negative correlation between c-erbB-2 expression and tumor stage. These results may suggest the contribution of c-erbB-1 molecule in progression of gastric carcinomas in southern Iranian patients. Moreover, the relatively high percentage of c-erbB-2 positive tumors may provide a useful target for the immunotherapy of these cancers.

Reversion of the malignant phenotype of gastric cancer cell SGC7901 by c-erbB-2-specific hammerhead ribozyme

The c-erbB-2/neu-encoded protein p185 is closely related to the growth and metastasis of adenocarcinoma. We sought to reverse the malignant phenotype of gastric cancer cell line SGC7901 with c-erbB-2-specific ribozyme. We designed the ribozyme and generated the in vitro transcription vectors of the ribozyme and its substrate. In vitro cleavage reaction indicated that the ribozyme catalyzed 79.3% target RNA in 1 hour at 37 degrees C. Then, we generated the eucaryotic expression vectors of the ribozyme and transfected them into SGC7901 cells, which highly express p185. Analyses showed that the c-erbB-2 mRNA and p185 were reduced remarkably in the ribozyme-transfected cells. The growth rate of the ribozyme-transfected cells was much lower than that of the control group. Tumorigenicity was also decreased dramatically in nude mice. The results demonstrated that c-erbB-2-specific ribozyme may inhibit the malignancy of gastric cancer cells SGC7901.

The HER-2/neu oncogene in tumors of the gastrointestinal tract

The HER-2/neu oncogene is localized to chromosome 17q and shares significant homology with the epidermal growth factor receptor. As a result of its potential role in the selection of therapy, HER-2/neu testing has reached near-standard-of-practice status in breast cancer. There is considerable interest in HER-2/neu as a prognostic factor and target of therapy in tumors of the gastrointestinal tract. In this review of HER-2/neu expression in esophageal squamous cell carcinoma and adenocarcinomas of the esophagus, stomach, and colon, a wide range of expression of HER-2/neu from 0 to 83% likely reflects both differences in methods and reagents, as well as study bias associated with patient selection (i.e., early versus advanced disease). For esophageal squamous cell carcinoma, little information exists as to the prognostic significance of HER-2/neu expression. In adenocarcinoma associated with Barrett's esophagus there is contradictory data. However, most of the information available indicates that this marker has significant prognostic value. In gastric adenocarcinoma, the wide expression range may truly reflect patient selection because HER-2/neu positivity appears linked to advanced rather than early disease with limited invasion. The majority of studies favor a significant prognostic value of HER-2/neu status for this tumor. Finally, in colorectal cancer HER-2/neu overexpression also appears to be a significant adverse outcome indicator as judged by the current published literature. In conclusion, given that either HER-2/neu protein overexpression or gene amplification is associated with approximately one-fourth of all gastrointestinal tract malignancies, strategies designed to employ the marker in therapy selection appear warranted. During the next several years it will not be surprising to see these tumors treated with antiHER-2/neu modalities such as Herceptin, likely in combination with other agents initially for patients with advanced disease, and possibly for individuals with high-risk lesions in an adjuvant setting.

Tyrosine kinases and gastric cancer

Carcinoma of the stomach is one of the most prevalent cancer types in the world today. Two major forms of gastric cancer are distinguished according to their morphological and clinicopathological classifications (well differentiated/intestinal type and poorly differentiated/diffuse type), characteristics that could also be attributed to the altered expression of different types of oncogenes or tumor suppressor genes. Significant differences exist for gastric cancer incidence comparing people of different ethnic origins, implicating various genetic and epigenetic factors for gastric oncogenesis. There are only a limited number of molecular markers available for gastric cancer detection and prognostic evaluation, among which are tyrosine kinases. There is convincing evidence that tyrosine kinases are involved in oncogenesis and disease progression for many human cancers. Amplifications of certain tyrosine kinases (c-met, k-sam and erbB2/neu) have been associated with human gastric cancer progression. Alternatively spliced transcripts and enhanced protein-expression levels for some of these tyrosine kinases are correlated with clinical outcomes for gastric cancer patients. With advent of high throughput techniques, it is now possible to detect nearly all expressed tyrosine kinases in a single screen. This increases the chance to identify additional tyrosine kinases as predictive markers for gastric cancers. In this article, we will first review the literature data concerning certain tyrosine kinases implicated in gastric carcinogenesis and then summarize more recent work which provide comprehensive tyrosine kinase profiles for gastric cancer specimens and cell lines. Two new gastric cancer molecular markers (tie-1 and mkk4) have been identified through the use of these profiles and demonstrated effective as clinical prognostic indicators.

Flow cytometric DNA ploidy, p53, PCNA, and c-erbB-2 protein expressions as predictors of survival in surgically resected gastric cancer patients

In order to determine retrospectively the impact of some cytometric and immunohistochemical parameters on the overall survival of gastric cancer patients treated with surgery alone, paraffin-embedded tumor samples from 137 gastric carcinoma patients undergoing curative resection from 1987-1993 were analyzed by flow cytometry (FCM) and immunohistochemistry (p53, c-erbB-2, and PCNA expression). FCM-derived parameters were DNA ploidy and fraction of S-phase cells (SPF). Multiple regression analysis was applied to determine the prognostic significance of the conventional clinicopathologic findings together with the flow cytometric and immunohistochemical parameters on overall survival. When all parameters were entered simultaneously into the Cox regression model, stage and DNA ploidy (DNA index >1.35) clearly emerged as the only independent prognostic factors. When the stages were analysed separately, the independent prognostic factors resulted DNA ploidy in early stages (I-II) and grading in stage IIIA tumors. For stage IIIB tumors, no independent prognostic factor was found. These results indicate that the DNA ploidy pattern is a valuable predictor of survival in curatively resected gastric cancer patients, especially when less advanced tumors are taken into consideration.

C-erbB-2 immunostaining in laryngeal cancer

Tumour progression is strongly associated with a series of specific genetic changes in protooncogenes and tumour suppressor genes. One of the potential factors involved in tumorogenesis of squamous cell carcinomas is protooncogene c-erbB-2 (also known as neu or HER2). The authors analysed the expression of c-erbB-2 oncoprotein in 154 cases of laryngeal squamous cell carcinomas and its relationship to the clinical outcome of the patients. The difference in c-erbB-2 oncoprotein expression between the control group and cancer patients was on the statistical borderline (p = 0.0470). There was no significant correlation between c-erbB-2 expression and sex and age of the patients. T stage, lymph node status, site and histopathological grading of the tumour and clinical outcome of the patients. Univariate analysis revealed no correlation between c-erbB-2 expression and survival rates. We conclude that immunohistological examination of c-erbB-2 on paraffin section is not a valuable prognostic factor in laryngeal carcinoma.