Epidermal growth factor receptor expression correlates with histologic grade in resected esophageal adenocarcinoma

The new N2, N4-diphenylpyridine-2,4-diamine deuterated derivatives as EGFR inhibitors to overcome C797S-mediated resistance

A series of new deuterated and non-deuterated N2, N4-diphenylpyridine - 2,4-diamine derivatives were synthesized and evaluated as EGFR C797S-mediated resistance inhibitors. Most of these compounds exhibited potent antiproliferative activity against Baf3-EGFR L858R/T790M/C797S and Baf3-EGFR Del19/T790M/C797S cancel cell lines, with IC50 values in the nanomolar concentration range. Among them, compound 14l represented the most active compound with IC50 values of 8-11 nM. Interestingly, metabolic stability assay with rat liver microsomes indicated that the half-life of the deuterated derivative 14o was significantly increased compared to that of 14l. In xenograft mice models, 14o inhibited tumor growth with excellent inhibitory rate of 75.1 % at the dosage of 40 mg/kg, comparing 73.2 % of the TGI with its non-deuterated compound 14l, at a dosage of 80 mg/kg. Mechanism studies revealed that 14o was a potent EGFR L858R/T790M/C797S and EGFR Del19/T790M/C797S kinase inhibitor, which could downregulate the protein phosphorylation of EGFR and m-TOR signaling pathways, arrest cell cycle at G2/M phase by affecting the expression of CDC25C, and promote cell apoptosis by regulating the expression of cleaved caspase-3. In summary, 14o could serve as a promising deuterated compound for the development of highly efficient anticancer agents.

Let-7c-5p Inhibits Cell Proliferation and Migration and Promotes Apoptosis via the CTHRC1/AKT/ERK Pathway in Esophageal Squamous Cell Carcinoma

PURPOSE

Let-7c-5p has been identified as a tumor suppressor in various malignancies; however, its function and mechanism in esophageal squamous cell carcinoma (ESCC) remain unclear. Here, we explored the role and potential molecular mechanism of let-7c-5p in ESCC.

MATERIALS AND METHODS

mRNA and protein expression levels were detected by quantitative real time-polymerase chain reaction (qRT-PCR) and Western blotting. The cell counting kit-8 (CCK-8) assay was used to assess cell proliferation. Flow cytometry analysis was used to detect cell apoptosis, and cell migration was measured by wound healing assay and Transwell assays. The dual-luciferase reporter assay was used to verify the targeting relationship between let-7c-5p and CTHRC1. The tumor xenograft model was constructed to further verify the effect of let-7c-5p on the growth of ESCC in vivo.

RESULTS

We found that let-7c-5p expression was downregulated in ESCC tissue and cell lines, and its reduced expression was correlated with TNM staging and lymph node metastasis. Next, we found that let-7c-5p can be used to discriminate ESCC patients from normal control subjects by receiver operating characteristic (ROC) curve analysis. Subsequently, we observed that let-7c-5p overexpression inhibited proliferation and migration and promoted apoptosis, while let-7c-5p down-regulation promoted proliferation and migration and inhibited apoptosis of TE-1 and KYSE150 cells. Furthermore, let-7c-5p overexpression inhibited tumor growth, while let-7c-5p inhibition promoted tumor growth in xenograft models. In addition, we confirmed that CTHRC1 was a direct target gene of let-7c-5p. Then, we found that let-7c-5p level was negatively correlated with CTHRC1 and negatively regulated expression of CTHRC1 in ESCC. Moreover, we confirmed that let-7c-5p upregulation significantly reduced the phosphorylation of AKT and ERK by directly inhibiting CTHRC1, while let-7c-5p downregulation showed the opposite effect.

CONCLUSION

Our findings indicate that let-7c-5p is markedly downregulated in ESCC and suppresses proliferation and migration and promotes apoptosis of ESCC cells by inhibiting the AKT and ERK signaling pathways through negatively regulating CTHRC1. Therefore, these results suggest that let-7c-5p may represent a novel biomarker and therapeutic target for ESCC.

Targeted Molecular Therapies in the Treatment of Esophageal Adenocarcinoma, Are We There Yet?

Esophageal adenocarcinoma is one of the leading causes of cancer-related deaths worldwide. The incidence of esophageal adenocarcinoma has increased at an alarming rate in the Western world and long-term survival remains poor. Current treatment approaches involve a combination of surgery, chemotherapy, and radiotherapy. Unfortunately, standard first-line approaches are met with high rates of recurrence and metastasis. More recent investigations into the distinct molecular composition of these tumors have uncovered key genetic and epigenetic alterations involved in tumorigenesis and progression. These discoveries have driven the development of targeted therapeutic agents in esophageal adenocarcinoma. While many agents have been studied, therapeutics targeting the human epidermal growth factor receptor (HER2) and vascular endothelial growth factor (VEGF) pathways have demonstrated improved survival. More recent advances in immunotherapies have also demonstrated survival advantages with monoclonal antibodies targeting the programmed death ligand 1 (PD-L1). In this review we highlight recent advances of targeted therapies, specifically agents targeting receptor tyrosine kinases, small molecule kinase inhibitors, and immune checkpoint inhibitors. While targeted therapeutics and immunotherapies have significantly improved survival, the benefits are limited to patients whose tumors express biomarkers such as PD-L1 and HER2. Survival remains poor for the remainder of patients with esophageal adenocarcinoma, underscoring the critical need for development of novel treatment strategies.

Targeted Therapies and Immunotherapies in the Treatment of Esophageal Cancers

Esophageal cancer (EC) is among the most frequent and deadly cancers around the world. While esophageal adenocarcinoma (EAC) has one of the fastest-growing incidences amongst cancers in the US, it also has one of the lowest survival rates due to the limited effective treatment options. Fortunately, in the past decade, two targeted therapies and an immunotherapy agent have been approved by the FDA for metastatic EAC and esophageal squamous cell carcinoma (ESCC), with several more currently being considered for approval. In terms of immunotherapies, in July 2019, the FDA approved the PD1 inhibitor pembrolizumab for second-line treatment of PDL1-positive, advanced or metastatic ESCC. Two years before, pembrolizumab had been approved for the third-line treatment of PDL1-positive EAC. The PD1 inhibitor nivolumab, which was found in one study to outperform chemotherapy irrespective of PDL1 status, has yet to secure FDA approval. In terms of targeted therapies, although as many as 90% of EC cases show upregulated EGFR, anti-EGFR therapy has not been shown to improve survival. Ramucirumab, an antibody targeting both VEGF and HER2/neu receptors, has been approved for the treatment of refractory EAC, while the anti-HER2 monoclonal antibody (mAb) trastuzumab has been approved as front-line treatment for HER2-positive cases which account for approximately 20% of ECs. Although these targeted therapies and immunotherapies have resulted in significant improvements in survival for specific patient populations that are positive for certain biomarkers, such as PDL1 and HER2/neu, the survival rates remain low for a large proportion of the metastatic EC patient population, necessitating the development of further targeted treatment options.

EGFR family and cMet expression profiles and prognostic significance in esophagogastric adenocarcinoma

BACKGROUND

Targeted therapy with anti-human epidermal growth factor receptor-2 (HER2) monoclonal antibody in patients with HER2 overexpressed esophagogastric adenocarcinoma (EGA) improves survival; however, the effect is transient due to the development of resistance. Some studies suggest that cMet overexpression provides cross talk for epidermal growth factor receptor (EGFR) and HER2 inhibition. We sought to characterize the expression profile of the EGFR family and cMet receptors in untreated, resected EGA.

METHODS

This retrospective analysis included all sequential patients with esophageal or gastroesophageal junction (GEJ) adenocarcinoma who underwent primary resection, without neoadjuvant therapy or HER2 inhibition, with adequate tissue, at the University of Florida from 2001 to 2011. Central blinded immunohistochemistry (IHC) was performed on tumor specimens with EGFR, HER2, HER3, HER4 and cMet expression scored as low (0, 1+) or high (2+, 3+). Demographic and tumor characteristics were compared using Fisher exact test. Kaplan-Meier curves and univariate analysis compared survival among different receptors.

RESULTS

Total 52 patients were included in the study with median age 66 years. High expression of EGFR (73%), HER2 (40%), HER3 (75%), HER4 (35%) and cMet (69%) was detected among the study group. HER3 and HER4 co-expression was found in 18 (35%) cases. Pan expression of all four EGFR family members with cMet was noted in only 17% of cases. On univariate analysis, tumor stage and depth correlated with survival, while cMet + HER3 +/- EGFR receptor co-expression trended towards a worse survival.

CONCLUSIONS

EGFR family and cMet are frequently co-expressed in treatment naïve resected EGA or GEJ tumors. Although our data do not significantly show receptor status as a prognostic factor, the co-expression profiles support for further investigation to improve targeting of this signal transduction axis.

Assessment of epidermal growth factor receptor mutation/copy number and K-ras mutation in esophageal cancer

BACKGROUND

The molecular status of epidermal growth factor receptor (EGFR) in esophageal cancer has not been well elucidated. The purpose of the study was to investigate the prevalence of EGFR and K-ras mutation, and EGFR gene copy number status as well as its association with clinicopathologic characteristics, and also to identify the prognostic value of EGFR gene copy number in esophageal cancer.

METHODS

EGFR mutation in exon 19/exon 21 and K-ras mutation in codon 12/codon 13 were detected by real-time PCR method, while EGFR gene copy number status was analyzed by fluorescent in situ hybridization (FISH). EGFR gene amplification and high polysomy were defined as high EGFR gene copy number status (FISH-positive), and all else were defined as low EGFR gene copy number status (FISH-negative). The relationship between EGFR gene copy number status and clinicpathologic characteristics was analyzed. Kaplan-Meier method and Cox proportional hazards regression model were employed to evaluate the effects of EGFR gene copy number status on the patients' survival.

RESULTS

A total of 57 esophageal squamous cell carcinoma (ESCC) patients and 9 esophageal adenocarcinoma (EADC) patients were enrolled in the study. EGFR mutation was identified in one patient who was diagnosed as ESCC with stage IIIC disease. K-ras mutation was identified in one patient who was diagnosed as EADC. In all, 34 of 66 (51.5%) samples were detected as FISH-positive, which includes 30 ESCC and 4 EADC tumor samples. The correlation analysis showed that FISH-positive was significantly associated with the tumor stage (P=0.019) and lymph node metastasis (P=0.005) in esophageal cancer patients, and FISH-positive was also significantly associated with the tumor stage (P=0.007) and lymph node metastasis (P=0.008) in ESCC patients. Cox regression analysis showed that high EGFR gene copy number was not a significant predictor of a poor outcome for esophageal cancer patients (P=0.251) or for ESCC patients (P=0.092), but esophageal cancer patients or ESCC patients with low EGFR gene copy number may have longer survival than those with high EGFR gene copy number according to the survival curve trends.

CONCLUSIONS

The results indicated that EGFR or K-ras mutation was rare in esophageal cancer, but high EGFR gene copy number is frequent, and correlated with advanced pathologic stage and more number of the metastatic regional lymph nodes, especially in ESCC. In addition, high EGFR gene copy number is likely to have a deleterious effect on prognosis of esophageal cancer patients or ESCC patients, although no statistical significance was reached in the study.

Expression and Prognostic Significance of Human Epidermal Growth Factor Receptors 1 and 3 in Gastric and Esophageal Adenocarcinoma

Background

Gastric and esophageal adenocarcinomas are major global cancer burdens. These cancer forms are characterized by a poor prognosis and a modest response to chemo- radio- and targeted treatment. Hence there is an obvious need for further enhanced diagnostic and treatment strategies. The aim of this study was to examine the expression and prognostic impact of human epidermal growth factor receptor 1 (HER1/EGFR) and 3 (HER3), as well as the occurrence of EGFR and KRAS mutations in gastric and esophageal adenocarcinoma.

Methods

Immunohistochemical expression of EGFR and HER3 was analysed in all primary tumours and a subset of lymph node metastases in a consecutive cohort of 174 patients with adenocarcinoma of the stomach, cardia and esophagus. The anti-HER3 antibody used was validated by siRNA-mediated knockdown, immunohistochemistry and quantitative real-time PCR. EGFR and KRAS mutation status was analysed by pyrosequencing tecchnology.

Results and Discussion

High EGFR expression was an independent risk factor for shorter overall survival (OS), whereas high HER3 expression was associated with a borderline significant trend towards a longer OS. KRAS mutations were present in only 4% of the tumours and had no prognostic impact. All tumours were EGFR wild-type. These findings contribute to the ongoing efforts to decide on the potential clinical value of different HERs and druggable mutations in gastric and esophageal adenocarcinomas, and attention is drawn to the need for more standardised investigational methods.

Phosphorylated AKT1 is associated with poor prognosis in esophageal squamous cell carcinoma

BACKGROUND

The epidermal growth factor receptor (EGFR) signaling pathway is important in regulating biological behaviors in many malignancies. We explored whether expression and activation of EGFR and several components on its downstream pathways have prognostic significance in patients with esophageal squamous cell carcinoma (ESCC).

METHODS

Expression of EGFR, phosphorylated (p)-EGFR, AKT1, p-AKT1, AKT2, p-AKT2, ERK1, ERK2, p-ERK1/2, STAT3, and p-STAT3 was assessed by immunohistochemical analysis of tissue microarrays for 275 ESCC patients who had undergone complete three-field lymphadenectomy. Spearman rank correlation tests were used to determine the relationships among protein expression, and Cox regression analyses were performed to determine the prognostic factors on overall survival (OS).

RESULTS

p-EGFR expression was correlated statistically with all of the other phosphorylated markers. Gender, N stage, and p-AKT1 expression were found to be independent prognostic factors for OS. Increased expression of p-AKT1 was associated with decreased patient survival. EGFR and p-EGFR expression was not significantly associated with patient survival.

CONCLUSION

Activation of AKT1 was associated with poor prognosis in ESCC.

Electrochemical aptamer/antibody based sandwich immunosensor for the detection of EGFR, a cancer biomarker, using gold nanoparticles as a signaling probe

Detection of epidermal growth factor receptor (EGFR) in biological fluids is of paramount importance, since it has significant application in cancer diagnosis, drug development, and therapy monitoring. EGFR is a cancer biomarker, and its overexpression is associated with the development of some types of cancer. Herein, we report on the development of a sensitive and selective electrochemical aptamer/antibody (Apt/Ab) sandwich immunosensor for detection of EGFR. In this study, a biotinylated anti-human EGFR Apt was immobilized on streptavidin-coated magnetic beads (MB) and served as a capture probe. A polyclonal anti-human EGFR Ab was conjugated to citrate-coated gold nanoparticles (AuNPs) and used as a signaling probe. In the presence of EGFR, an Apt-EGFR-Ab sandwich was formed on the MB surface. The extent of the complexation was evaluated by differential pulse voltammetry of AuNPs after their dissolution in HCl. Under optimal conditions, the dynamic concentration range of the immunosensor for EGFR spanned from 1 to 40 ng/mL, with a low detection limit of 50 pg/mL, and RSD percent of less than 4.2%. The proposed approach takes advantage of sandwich assay for high specificity, MBs for fast separation, and electrochemical method for cost-effective and sensitive detection. In this proof-of-principle study, we demonstrate the potential clinical efficacy of the immunosensor for monitoring of chemotherapy effectiveness in breast cancer samples.

Gastric cancer and the epoch of immunotherapy approaches

The incidence of gastric cancer (GC) fell dramatically over the last 50 years, but according to IARC-Globocan 2008, it is the third most frequent cause of cancer-related deaths with a case fatality GC ratio higher than other common malignancies. Surgical resection is the primary curative treatment for GC though the overall 5-year survival rate remains poor (approximately 20%-25%). To improve the outcome of resectable gastric cancer, different treatment strategies have been evaluated such as adjuvant or perioperative chemotherapy. In resected gastric cancer, the addition of radiotherapy to chemotherapy does not appear to provide any additional benefit. Moreover, in metastatic patients, chemotherapy is the mainstay of palliative therapy with a median overall survival of 8-10 mo and objective response rates of merely 20%-40%. Therefore, the potential for making key beneficial progress is to investigate the GC molecular biology to realize innovative therapeutic strategies, such as specific immunotherapy. In this review, we provide a panoramic view of the different immune-based strategies used for gastric cancer treatment and the results obtained in the most significant clinical trials. In detail, firstly we describe the therapeutic approaches that utilize the monoclonal antibodies while in the second part we analyze the cell-based immunotherapies.

The role of biological markers of epithelial to mesenchymal transition in oesophageal adenocarcinoma, an immunohistochemical study

BACKGROUND

E-cadherin, β-catenin, epidermal growth factor receptor (EGFR), neuronal cadherin (N-cadherin) and Cyclin D1 are involved in epithelial to mesenchymal transition (EMT). However, the prognostic significance of EMT markers in oesophageal adenocarcinoma (OAC) is unknown. Aim of this study was to evaluate the prognostic value of, and the association between different EMT markers in OAC.

METHODS

Tumour cores of 154 patients with OAC were included in a tissue microarray. Scoring criteria was based on immunohistochemical staining intensity.

RESULTS

EMT-associated markers were expressed in OAC: reduced membranous E-cadherin and β-catenin were seen in 11.4% and 51.7%, nuclear β-catenin in 19.1% and EGFR and Cyclin D1 overexpression in 56.5% and 27.4% of tumours. Mesenchymal marker N-cadherin was not expressed in OAC. A positive correlation was seen between membranous β-catenin and E-cadherin expression (R=0.209, p=0.001) and between EGFR and Cyclin D1 (R=0.257, p=0.002). In univariate analysis, EGFR overexpression and membranous β-catenin staining were significantly associated with a poor survival (HR 2.145; 95% CI 1.429 to 3.218, p<0.001 and HR 1.665; 95% CI 1.114 to 2.488; p=0.013). However, Cyclin D1 (HR 1.092; 95% CI 0.702 to 1.698; p=0.697), nuclear β-catenin (HR 1.322; 95% CI 0.799 to 2.189; p=0.277) and E-cadherin (HR 1.012; 95% CI 0.554 to 1.851; p=0.968) were not associated with survival. In multivariate analysis, EGFR overexpression was an independent prognostic factor for poor survival (HR 1.678; 95% CI 1.055 to 2.668; p=0.029) together with T stage (HR 2.759; 95% CI 1.356 to 5.576; p=0.005).

CONCLUSIONS

This study supports the presence of EMT in OAC. Moreover, EGFR overexpression was independently associated with a poor survival.

Histopathologic characteristics of gastric adenocarcinoma in Mexican patients: a 10-year experience at the Hospital Juárez of Mexico

BACKGROUND

Gastric cancer is the second cause of death by cancer worldwide. Histologic classification may predict tumor biology, clinical behavior, and outcome. According to the Lauren classification, the disease is divided into 2 types, diffuse and intestinal, and the latter has a better prognosis.

AIM

To determine the frequency of gastric adenocarcinoma and compare the histopathologic characteristics of intestinal and diffuse-type gastric adenocarcinoma in Mexican patients treated at a tertiary referral hospital.

METHODOLOGY

A retrospective study evaluated the pathology reports of patients with gastric adenocarcinoma corresponding to the time frame of January 2003 to December 2012. Adenocarcinomas of the gastric cardia were excluded. Frequencies were expressed as percentages and the categorical variables were compared with the chi-square test. Statistical significance was set at a P<.05.

RESULTS

A total of 417 cases of gastric adenocarcinoma were found, 230 (55.2%) of which were diffuse-type and 118 (28.2%) were intestinal-type. The mean age of the patients with diffuse type gastric cancer was 54.02±14.93 and 119 (51.3%) of those patients were men. The mean age of the patients with intestinal-type gastric cancer was 63.43±13.78, and 69 (62.2%) were men. Ninety-two of the diffuse-type patients were under the age of 50 years, compared with 22 of the patients with intestinal-type carcinoma.

CONCLUSIONS

This is the first study on the Mexican population to analyze the differences in the histologic types of adenocarcinoma. Diffuse-type gastric carcinoma was the most frequent subtype in our study population and it is associated with worse outcome.

Clinicopathological and prognostic significance of epidermal growth factor receptor overexpression in patients with esophageal adenocarcinoma: a meta-analysis

The prognostic significance of epidermal growth factor receptor (EGFR) overexpression in patients with esophageal adenocarcinoma (EAC) remains controversial. Eligible studies that investigated the association between survival in EAC and the expression status of EGFR were identified by an electronic search of PubMed, EMBASE, and ISI Web of Science. A meta-analysis was performed to clarify the impact of EGFR overexpression on clinicopathological parameters or overall survival (OS) in EAC. A total of seven studies including 1028 patients were subjected to the final analysis. The overall results suggested that overexpression of EGFR was significantly correlated with not only the depth of invasion, lymph node status, and tumors stage of EAC, with a pooled odds ratio of 2.99 (95% confidence interval [CI]: 1.07-8.35; Z = 2.09; P = 0.037), 3.05 (95% CI: 1.77-5.27; Z = 4.00; P < 0.001), and 5.37 (95% CI: 2.49-11.57; Z = 4.29; P < 0.001), respectively, but also the poorer OS with a pooled hazard ratio of 2.20 (95% CI: 1.47-3.31; Z = 3.79; P < 0.001). Overexpression of EGFR correlates with not only the clinicopathological features, but also the worse OS, and it might be useful as a predictive biomarker in clinical practice, yet the clinicopathological and prognostic role of EGFR in EAC still needs further confirmation by well-designed prospective studies.

Featured article: autophagic activation with nimotuzumab enhanced chemosensitivity and radiosensitivity of esophageal squamous cell carcinoma

Chemotherapy and radiotherapy are two indispensible methods for esophageal squamous cell carcinoma (ESCC), especially for those recurring and metastatic ones, but therapeutic toxicity remains a major problem to overcome. In the present study, the potential therapeutic value of nimotuzumab (an antiepidermal growth factor receptor [EGFR] monoclonal antibody) in combination with chemotherapy and radiotherapy was evaluated on Eca109 and TE-1 ESCC cells, with high and low expression of EGFR, respectively. It was shown that nimotuzumab enhanced the sensitivity of Eca109 cells to other cytotoxic agents (paclitaxel and cis-platinum) and X-ray radiation, and the cytotoxicity was associated with increased autophagy. Conversely, the chemo- and radio-sensitivity of TE-1 cells showed no improvement with addition of nimotuzumab, but could be increased by combining with rapamycin, an autophagy inducer. Therefore, it was concluded that autophagic activation mediated by nimotuzumab could promote autophagic cell death and produce additive antitumor effects.

Emerging tyrosine kinase inhibitors for esophageal cancer

INTRODUCTION

Because of the poor prognosis for patients with esophagogastric cancers (EGCs), increasing attention has focused on targeted agents.

AREAS COVERED

Targets include epidermal growth factor receptor (EGFR), vascular endothelial growth factor (VEGF), Her2, mammalian target of rapamycin (mTOR), and MET. We briefly discuss preclinical data and the rationale for targeting these pathways and summarize the results of clinical trials of tyrosine kinase inhibitors (TKIs) against these targets.

EXPERT OPINION

While anti-EGFR therapy has been extensively investigated, completed Phase III trials suggest that this is not a promising target. A Phase III trial of an anti-VEGF antibody failed to show improvement in the primary endpoint of overall survival but response rates and progression-free survival were improved; a Phase III trial of an anti-VEGF receptor 2 antibody in second-line therapy did show improved survival. As such, Phase II and III evaluations of anti-VEGF TKIs are ongoing. The only Food and Drug Administration-approved targeted therapy in EGC is trastuzumab, an anti-Her2 antibody, and the results of a Phase III evaluation of lapatinib, an anti-Her2 TKI, are awaited. Phase III evaluation of an mTOR inhibitor has been negative. Finally, MET inhibition appears to have significant clinical potential and early testing of MET TKIs is underway.

Gastric cancer-molecular and clinical dimensions

Gastric cancer imposes a considerable health burden around the globe despite its declining incidence. The disease is often diagnosed in advanced stages and is associated with a poor prognosis for patients. An in-depth understanding of the molecular underpinnings of gastric cancer has lagged behind many other cancers of similar incidence and morbidity, owing to our limited knowledge of germline susceptibility traits for risk and somatic drivers of progression (to identify novel therapeutic targets). A few germline (PLCE1) and somatic (ERBB2, ERBB3, PTEN, PI3K/AKT/mTOR, FGF, TP53, CDH1 and MET) alterations are emerging and some are being pursued clinically. Novel somatic gene targets (ARID1A, FAT4, MLL and KMT2C) have also been identified and are of interest. Variations in the therapeutic approaches dependent on geographical region are evident for localized gastric cancer-differences that are driven by preferences for the adjuvant strategies and the extent of surgery coupled with philosophical divides. However, greater uniformity in approach has been noted in the metastatic cancer setting, an incurable condition. Having realized only modest successes, momentum is building for carrying out more phase III comparative trials, with some using biomarker-based patient selection strategies. Overall, rapid progress in biotechnology is improving our molecular understanding and can help with new drug discovery. The future prospects are excellent for defining biomarker-based subsets of patients and application of specific therapeutics. However, many challenges remain to be tackled. Here, we review representative molecular and clinical dimensions of gastric cancer.

Expression of epidermal growth factor receptor is an independent prognostic factor for esophageal squamous cell carcinoma

BACKGROUND

The overall survival of patients with esophageal squamous cell carcinoma (ESCC) remains poor. Prognostic predictions in ESCC are usually based on histological assessment of tumor invasion and lymph node metastasis, but a biomarker with better predictive accuracy could be more useful. Because overexpression of epidermal growth factor receptor (EGFR) has been associated with poor prognosis, this study investigated whether EGFR is an independent prognostic factor for overall survival and disease-free survival of ESCC patients.

METHODS

ESCC tissue specimens from 243 patients obtained during surgical resection between 1980 and 1997 were retrieved for immunohistochemical analysis of EGFR expression.

RESULTS

The data showed that EGFR protein was overexpressed in 187 of 243 (77%) ESCC tissues. Elevated expression was associated with higher pathologic tumor stages (P = 0.001), lymph node metastasis (P = 0.002), and higher Union for International Cancer Control (UICC) stage (P <0.0001), as well as poorer disease-free survival and overall survival of ESCC patients (P <0.0001). A multivariate analysis showed that overexpression of EGFR protein was an independent factor for disease-free survival (P = 0.003) and overall survival (P = 0.001) of these patients. Subgroup analysis of patients with stage IIA (UICC 2002) showed that EGFR overexpression was associated with poorer disease-free survival (P = 0.007) and overall survival (P = 0.010) of the patients in univariate analyses.

CONCLUSIONS

The current study demonstrated that EGFR overexpression was an independent prognostic factor for overall survival and disease-free survival of ESCC patients. However, targeting of EGFR activity using gefitinib or erlotinib could be useful for clinical treatment of ESCC patients.

Gastric cancer-molecular and clinical dimensions

Gastric cancer imposes a considerable health burden around the globe despite its declining incidence. The disease is often diagnosed in advanced stages and is associated with a poor prognosis for patients. An in-depth understanding of the molecular underpinnings of gastric cancer has lagged behind many other cancers of similar incidence and morbidity, owing to our limited knowledge of germline susceptibility traits for risk and somatic drivers of progression (to identify novel therapeutic targets). A few germline (PLCE1) and somatic (ERBB2, ERBB3, PTEN, PI3K/AKT/mTOR, FGF, TP53, CDH1 and MET) alterations are emerging and some are being pursued clinically. Novel somatic gene targets (ARID1A, FAT4, MLL and KMT2C) have also been identified and are of interest. Variations in the therapeutic approaches dependent on geographical region are evident for localized gastric cancer-differences that are driven by preferences for the adjuvant strategies and the extent of surgery coupled with philosophical divides. However, greater uniformity in approach has been noted in the metastatic cancer setting, an incurable condition. Having realized only modest successes, momentum is building for carrying out more phase III comparative trials, with some using biomarker-based patient selection strategies. Overall, rapid progress in biotechnology is improving our molecular understanding and can help with new drug discovery. The future prospects are excellent for defining biomarker-based subsets of patients and application of specific therapeutics. However, many challenges remain to be tackled. Here, we review representative molecular and clinical dimensions of gastric cancer.

Clinical significance of the expression of EGFR signaling pathway-related proteins in esophageal squamous cell carcinoma

Epidermal growth factor receptor (EGFR) signaling is an important pathway that is not only involved in the determination of cellular development, but also has significant roles in tumor development and progression. The study aims to examine the expression of EGFR signaling pathway-related proteins (EGFR, c-Fos, and c-erb-B2) in esophageal squamous cell carcinoma and to investigate their relationships with clinical significance. Sixty esophageal squamous carcinoma specimens obtained by fiber esophagoscope were subjected to two-step immunohistochemistry to test the expression of EGFR, c-Fos, and c-erb-B2. EGFR expression was observed in 73.3% of tumors (44/60); positive EGFR expression was significantly correlated with tumor-node-metastasis (TNM) staging, lymph node metastasis, and distant metastasis (P < 0.05). c-Fos expression was found in 85% (51/60) of tumors, and its expression was significantly related to tumor depth and TNM staging (P < 0.05). c-erb-B2 expression was 75% (45/60) in esophageal squamous cell carcinoma (ESCC) specimens, and positive-erb-B2 expression had a significant association with the depth of tumor invasion (P < 0.05). c-Fos expression was significantly and positively correlated with c-erb-B2 (P < 0.05). Overexpression of EGFR, c-Fos, and c-erb-B2 was associated with tumor progression and development. EGFR and c-Fos expression can predict the tumor stage. c-Fos and c-erb-B2 expression can be used to determine the depth of tumor invasion and can also act as a combined prognostic indicator in ESCC.

New and emerging combination therapies for esophageal cancer

Esophageal cancer comprises two different histological forms - squamous cell carcinoma (SCC) and adenocarcinoma (AC). While the incidence of AC has increased steeply in Western countries during the last few years, the incidence of SCC is fairly stable. Both forms differ in pathogenesis and response to chemotherapy and radiation therapy. Plenty of studies have evaluated new chemotherapy combination regimens in the neoadjuvant, adjuvant, and palliative setting. In addition, new radiation and chemoradiation protocols have been investigated. Finally, molecular-targeted therapy has been included in several new randomized prospective trials. Therefore, this review presents new data on this topic and critically discusses promising approaches towards a more effective treatment in a disease with a grim prognosis.

Immunotherapy for gastrointestinal malignancies

BACKGROUND

Gastrointestinal (GI) cancers are the most common human tumors encountered worldwide. The majority of GI cancers are unresectable at the time of diagnosis, and in the subset of patients undergoing resection, few are cured. There is only a modest improvement in survival with the addition of modalities such as chemotherapy and radiation therapy. Due to an increasing global cancer burden, it is imperative to integrate alternative strategies to improve outcomes. It is well known that cancers possess diverse strategies to evade immune detection and destruction. This has led to the incorporation of various immunotherapeutic strategies, which enable reprogramming of the immune system to allow effective recognition and killing of GI tumors.

METHODS

A review was conducted of the results of published clinical trials employing immunotherapy for esophageal, gastroesophageal, gastric, hepatocellular, pancreatic, and colorectal cancers.

RESULTS

Monoclonal antibody therapy has come to the forefront in the past decade for the treatment of colorectal cancer. Immunotherapeutic successes in solid cancers such as melanoma and prostate cancer have led to the active investigation of immunotherapy for GI malignancies, with some promising results.

CONCLUSIONS

To date, monoclonal antibody therapy is the only immunotherapy approved by the US Food and Drug Administration for GI cancers. Initial trials validating new immunotherapeutic approaches, including vaccination-based and adoptive cell therapy strategies, for GI malignancies have demonstrated safety and the induction of antitumor immune responses. Therefore, immunotherapy is at the forefront of neoadjuvant as well as adjuvant therapies for the treatment and eradication of GI malignancies.

Signaling pathways in the molecular pathogenesis of adenocarcinomas of the esophagus and gastroesophageal junction

Esophageal adenocarcinoma develops in response to severe gastroesophageal reflux disease through the precursor lesion Barrett esophagus, in which the normal squamous epithelium is replaced by a columnar lining. The incidence of esophageal adenocarcinoma in the United States has increased by over 600% in the past 40 years and the overall survival rate remains less than 20% in the community. This review highlights some of the signaling pathways for which there is some evidence of a role in the development of esophageal adenocarcinoma. An increasingly detailed understanding of the biology of this cancer has emerged recently, revealing that in addition to the well-recognized alterations in single genes such as p53, p16, APC, and telomerase, there are interactions between the components of the reflux fluid, the homeobox gene Cdx2, and the Wnt, Notch, and Hedgehog signaling pathways.

Molecular targeted therapies in advanced gastric cancer: does tumor histology matter?

It is increasingly recognized that gastric cancer is a heterogeneous disease which may be divided into subgroups based on histological, anatomical, epidemiological and molecular classifications. Distinct molecular drivers and tumor biology, and thus different treatment targets and predictive biomarkers, may be implicated in each subtype. However, there is little evidence in the literature regarding the correlation among these different classifications, and particularly the molecular aberrations present in each subtype. In this review, we approach advanced gastric cancer (AGC) by presenting aberrant molecular pathways and their potential therapeutic targets in gastric cancer according to histological and anatomical classification, dividing gastric cancer into proximal nondiffuse, distal nondiffuse and diffuse disease. Several pathways are involved predominantly, although not exclusively, in different subtypes. This may help to explain the disappointing results of many published AGC trials in which study populations were heterogeneous regardless of clinicopathological characteristics of the primary tumor. Histological and anatomical classification may provide insights into tumor biology and facilitate selection of an enriched patient population for targeted agents in future studies and in the clinic. However, some molecular pathways implicated in gastric cancer have not been studied in correlation with histological or anatomical subtypes. Further studies are necessary to confirm the suggestion that such classification may predict tumor biology and facilitate selection of an enriched patient population for targeted agents in future studies and in the clinic.

Increase of epidermal growth factor receptor expression in progression of GERD, Barrett, and adenocarcinoma of esophagus

INTRODUCTION

Gastroesophageal reflux disease (GERD) is a pathology with a wide range of clinical and endoscopic manifestations. Epidermal growth factor receptor (EGFR), found in the epithelium of the digestive tract, plays an important role in epithelial repair and shows increased expression in different neoplasms, including esophageal tumors.

OBJECTIVES

The purpose of this study was to evaluate EGFR expression using immunohistochemistry in esophageal biopsies obtained from patients with GERD, Barrett's esophagus, and adenocarcinoma of the esophagus.

METHODS

EGFR expression was immunohistochemically determined in biopsies from 194 patients with symptoms suggestive of GERD or adenocarcinoma of the esophagus, seen at two Brazilian university hospitals between January 2003 and December 2008. Based on histopathological analysis, patients were divided into three groups: GERD, Barrett's esophagus and adenocarcinoma of the esophagus. EGFR expression was considered positive when staining was detected in the membrane.

RESULTS

Mean age was 55.25 years (range 30-90). Patients with GERD (n = 127) accounted for 65.5% of the sample, compared with 12.4% (n = 24) of patients with Barrett's esophagus and 22.2% (n = 43) of patients with esophageal adenocarcinoma. Immunohistochemical analysis was positive for EGFR in 19.1% of the patients (37/194), divided as follows: 8.7% (11/127) in the GERD group, 25% (6/24) in the Barrett's esophagus group, and 46.5% (20/43) in the esophageal adenocarcinoma group. Statistical analysis revealed significant differences between the three groups (p = 0.0001).

CONCLUSIONS

GERD patients showed lower levels of EGFR expression than patients with Barrett's esophagus or patients with adenocarcinoma of the esophagus, suggesting a direct relationship between EGFR expression and disease progression.

Nimotuzumab promotes radiosensitivity of EGFR-overexpression esophageal squamous cell carcinoma cells by upregulating IGFBP-3

Background

Epidermal growth factor receptor (EGFR) is suggested to predict the radiosensitivity and/or prognosis of human esophageal squamous cell carcinoma (ESCC). The objective of this study was to investigate the efficacy of Nimotuzumab (an anti-EGFR monoclonal antibody) on ESCC radiotherapy (RT) and underlying mechanisms.

Methods

Nimotuzumab was administrated to 2 ESCC cell lines KYSE30 and TE-1 treated with RT. Cell growth, colony formation and apoptosis were used to measure anti-proliferation effects. The method of RNA interference was used to investigate the role of insulin-like growth factor binding protein-3 (IGFBP-3) in ESCC cells radiosensitivity treated with Nimotuzumab. In vivo effect of Nimotuzumab on ESCC radiotherapy was done using a mouse xenograft model.

Results

Nimotuzumab enhanced radiation response of KYSE30 cells (with high EGFR expression) in vitro, as evidenced by increased radiation-inhibited cell growth and colony formation and radiation-mediated apoptosis. Mechanism study revealed that Nimotuzumab inhibited phosphorylated EGFR (p-EGFR) induced by EGF in KYSE30 cells. In addition, knockdown of IGFBP-3 by short hairpin RNA significantly reduced KYSE30 cells radiosensitivity (P<0.05), and even after the administration of Nimotuzumab, the RT response of IGFBP-3 silenced KYSE30 cells was not enhanced (P>0.05). In KYSE30 cell xenografts, Nimotuzumab combined with radiation led to significant tumor growth delay, compared with that of radiation alone (P=0.029), and also with IGFBP-3 up-regulation in tumor tissue.

Conclusions

Nimotuzumab could enhance the RT effect of ESCC cells with a functional active EGFR pathway. In particular, the increased ESCC radiosensitivity by Nimotuzumab might be dependent on the up-regulation of IGFBP-3 through EGFR-dependent pathway.

Current developments in the management of locally advanced esophageal cancer

Loco-regionally advanced esophageal cancer is a lethal disease with poor outcomes despite aggressive multimodality therapy. The appropriate management of these patients is contentious and no single standard of care has been defined. Literature suggests that preoperative chemoradiotherapy may be superior to preoperative chemotherapy. Recently, several developments have impacted the care of these patients. The 2010 AJCC TNM staging system now recognizes the biologic heterogeneity of the disease and stages adenocarcinoma and squamous cell carcinoma separately. Studies suggest potentially less toxic chemotherapeutic agents including oxaliplatin may be useful in the management of this disease. FDG-PET imaging appears to have prognostic value and may predict for pathologic response. In addition, several trials have explored inhibition of the ErbB1 (EGFR) and ErbB2 (Her2) receptors. The monoclonal antibody trastuzumab appears to extend survival for patients with metastatic gastric and gastroesophageal junction adenocarcinoma and is under investigation for use in patients with loco-regionally advanced disease.

Promising outcomes of definitive chemoradiation and cetuximab for patients with esophageal squamous cell carcinoma

This study investigated cetuximab added to definitive concurrent chemoradiation for esophageal squamous cell carcinoma (ESCC). Previously untreated patients with stage II-IVa ESCC received cetuximab (400 mg/m(2) per week in week 1, then 250 mg/m(2) per week during weeks 2-8), paclitaxel (45 mg/m(2) per week) and cisplatin (20 mg/m(2) per week) in weeks 2-8 with 59.4 Gy radiotherapy. Epidermal growth factor receptor (EGFR) status in tumor specimens was assessed. Thirty-one patients were enrolled and evaluated for toxicity. Of the 29 patients assessable for a response, 20 (69.0%) had a clinical complete response (CR). Over a median follow up of 23.6 months, disease progression was observed in seven patients. The 1- and 2-year progression-free survival (PFS) rates were 85.5% and 75.1%, respectively. The PFS was shorter for patients with lymphatic metastatic disease than for those with locally confined tumor; the 1-year PFS rates were 78.7% and 92.3%, respectively (P = 0.038). Sixteen (55.2%) patients were immunohistochemically positive for EGFR. The patients with EGFR-expressing tumor had a CR rate of 75.0% compared with 61.5% in those with negative EGFR expression (P = 0.024). The PFS for patients with EGFR-expressing tumor was longer compared with the PFS of patients with negative EGFR (P = 0.133). The patients with prominent cetuximab-induced rash (≥grade 2) had a better CR rate and PFS than those with no or grade 1 rash (P < 0.05). The rates of grades 3/4 esophagitis, hematological and dermatological toxicities were 9.7%, 29.0% and 16.1%, respectively. The regimen of definitive chemoradiation plus cetuximab achieved good clinical response and has an acceptable safety profile in Chinese ESCC patients.

Molecular basis of esophageal cancer development and progression

This article discusses the molecular basis of esophageal cancer development and subsequent progression of disease. Differing epidemiologic factors are associated with esophageal adenocarcinoma and squamous cell carcinoma. These 2 different histologic types have differing putative underlying mechanisms of transdifferentiation from normal esophageal mucosa to malignant histologies via gene dysregulation, biochemical modifications, and altered cell signaling pathways. Our developing understanding of the molecular events underlying esophageal cancer is leading to the establishment of identifiable biomarkers and the clinical use of molecularly targeted treatment agents. The identification of driving genetic mutations and altered signaling pathways has also had favorable outcomes.

Epidermal growth factor receptor expression in esophageal adenocarcinoma: relationship with tumor stage and survival after esophagectomy

Background and Aims. Esophageal adenocarcinoma (EA) is an aggressive tumor with increasing incidence in occidental countries. Several prognostic biomarkers have been proposed, including epidermal growth factor receptor (EGFR). The aim of this study was to assess whether EGFR expression predicts EA staging and patient survival. Methods. In this historical cohort, consecutive patients with EA managed between 2000 and 2010 were considered eligible for the study. Surgical specimens of patients treated with transhiatal esophagectomy were evaluated to establish EGFR expression and tumor differentiation. Staging was classified according with tumor-node-metastasis (TNM) system. Survival was determined according to either medical register or patient's family contact. Results. Thirty-seven patients who underwent esophagectomy without presurgical chemotherapy or radiotherapy were studied. EGFR expression was found in 16 patients (43%). EGFR expression was more frequent as higher was the TNM (I and II = 0% versus III = 47% versus IV = 100%; P < 0.001). Average survival in months was significantly shorter in the group of patients with EGFR expression (10.5 versus 21.7; P = 0.001). Conclusions. In patients with esophageal adenocarcinoma treated with transhiatal esophagectomy, EGFR expression was related to higher TNM staging and shorter survival. EGFR expression might be assumed as a prognostic marker for esophageal adenocarcinoma.

The overexpression of IGFBP-3 is involved in the chemosensitivity of esophageal squamous cell carcinoma cells to nimotuzumab combined with cisplatin

Nimotuzumab is an antibody against epidermal growth factor receptor (EGFR). The objective of this study was to examine the capacity and specific underlying mechanisms of nimotuzumab to modulate cytotoxicity of cisplatin (DDP) in esophageal squamous cell carcinoma (ESCC) cell lines with different EGFR expression levels. Nimotuzumab was administrated to two ESCC cell lines KYSE30 and TE-1 treated with DDP. Cell growth, colony formation, and apoptosis were analyzed by MTT and flow cytometry assays. The method of RNA interference was used to investigate the role of insulin-like growth factor binding protein-3 (IGFBP-3) in ESCC cells chemosensitivity treated with nimotuzumab. Combination of nimotuzumab and DDP resulted in a DDP cytotoxicity increase in overexpressing EGFR cells (KYSE30) but not in low-expressing EGFR cells (TE-1). Meantime, DDP activated the EGFR pathway in the two cell lines in a ligand-independent fashion. Furthermore, DDP-induced EGFR activation was inhibited by nimotuzumab in KYSE30 cells, and this result was not observed in TE-1 cells. EGF reduced the expression of IGFBP-3 in KYSE30 cells; however, nimotuzumab could reverse the downregulation of IGFBP-3, and this result was also not observed in TE-1 cells. After IGFBP-3 was silenced by small interfering RNA, the potential of nimotuzumab to enhance DDP-mediated cytotoxicity was inhibited in KYSE30 cells. The results indicated that the increased ESCC chemosensitivity to DDP by nimotuzumab might be dependent on IGFBP-3 upregulation through EGFR-dependent pathway, which would facilitate preselection of ESCC patients for treatment of nimotuzumab combined with DDP.

Novel immunotherapeutic strategies of gastric cancer treatment

Gastric cancer (GC) is the fourth most common cancer and the second most frequent cause of cancer-related deaths, accounting for 10.4% of cancer deaths worldwide. Despite the improvements, estimated cure rates for patients with advanced stages remain poor, and in the metastatic setting, chemotherapy is the mainstay of palliative therapy and results in objective response rates (ORRs) of only 20-40% and median overall survivals (OS) of 8-10 months. Therefore, many investigators believe that the potential for making significant progress lies in understanding and exploiting the molecular biology of these tumors to investigate new therapeutic strategies to combat GC, such as specific immunotherapy. In this paper, we analyze the different approaches used for immune-based (especially dendritic and T cells) therapies to gastric cancer treatment and discuss the results obtained in preclinical models as in clinical trials.

The dichotomy in carcinogenesis of the distal esophagus and esophagogastric junction: intestinal-type vs cardiac-type mucosa-associated adenocarcinoma

Adenocarcinoma of the distal esophagus and esophagogastric junction continues to rise in incidence. An intestinal metaplasia (Barrett esophagus)-dysplasia-carcinoma sequence induced by gastroesophageal reflux disease is well established. However, a significant number of adenocarcinomas in the vicinity of the esophagogastric junction are seen in the background of gastric/cardiac-type mucosa without intestinal metaplasia. Thus, the aim of this study was to investigate the role of Barrett esophagus (intestinal-type mucosa) in the classification and prognosis of tumors of the distal esophagus and esophagogastric junction. Clinicopathological and molecular characteristics were examined in 157 consecutively resected adenocarcinomas of the distal esophagus and esophagogastric junction and were compared between tumors arising in association with intestinal-type and cardiac-type mucosa. Intestinal-type mucosa-associated adenocarcinomas were more likely to be associated with younger age (P=0.0057), reflux symptoms (P<0.0001), proximal location (P=0.0009), lower T stage (P<0.0001), fewer nodal metastases (P=0.0001), absence of lymphatic (P<0.0001), venous (P=0.0060) or perineural (P<0.0001) invasion. Histologically, intestinal-type mucosa-associated tumors were more likely to be low-grade glandular tumors (P=0.0095) of intestinal or mixed immunophenotype (P=0.015) and express nuclear β-catenin (P=0.0080), whereas tumors arising in a background of cardiac-type mucosa were more frequently associated with EGFR amplification (P=0.0051). Five-year overall survival rate was significantly higher in patients with intestinal-type mucosa-associated tumors (28 vs 9%, P=0.0015), although no survival benefit was seen after adjusting for potential confounders. Our findings support the theory that multiple distinct pathways of tumorigenesis exist in the vicinity of the esophagogastric junction, including one in which tumors arise from dysplastic intestinal metaplasia (intestinal pathway), and one potentially involving dysplasia of the cardiac-type mucosa (non-intestinal pathway). Additional studies are warranted to further clarify their pathogenesis and the molecular mechanisms involved.

Molecular imaging for guiding oncologic prognosis and therapy in esophageal adenocarcinoma

In the past 30 years, the incidence of esophageal adenocarcinoma (ACA) has increased significantly. Sadly, advances in treatment have not followed the same trend, and the prognosis for patients with esophageal ACA remains poor, with a 5-year survival rate of only 15%. Like most cancers, early detection is the key to improving prognosis, but this outcome has proven difficult in the esophagus for several reasons: 1) patients present with advanced disease because "alarm symptoms," such as dysphagia, occur at a late stage, and 2) high-grade dysplasia (HGD) and early ACA are not visible on routine surveillance endoscopy. Currently, the recommended surveillance strategy involves collection of random biopsies, an imperfect technique that is limited by sampling error and is infrequently used because of the considerable time and cost it requires. Even in patients with biopsy-proven dysplasia, adequate guidance for clinical management decisions is still lacking. Dysplasia alone is not an entirely reliable biomarker for the risk of progression to ACA because the natural history of this condition is extremely variable. Clearly, there is a need for additional biomarkers that can better characterize this disease and thus improve our ability to treat patients on an individual basis. As we better understand the molecular changes that lead to the development of this cancer, new molecular biomarkers are needed to allow for more personalized diagnoses, surveillance, and treatment. Targeted agents against epidermal growth factor receptor (EGFR), human epidermal growth factor receptor 2 (HER2), and vascular endothelial growth factor (VEGF) are currently being evaluated for their role in combination chemotherapy for metastatic esophageal ACA. As these studies progress, a reliable approach for determining receptor status in individual patients is essential. Molecular imaging uses fluorescent probes that target specific cell-surface receptors, and has the potential to evaluate an individual patient's gene expression profile. By topically applying fluorescent probes to dysplastic epithelium during endoscopy, a variety of receptors can be visualized, and the response to treatment can be monitored in real time. This technique can mitigate the limitations of current surveillance protocols, allow for improved cancer detection, and be used for personalized treatment in the future.

Targeted therapies for metastatic esophagogastric cancer

The prognosis and long-term survival for patients with metastatic esophagogastric cancer (EGC) is poor. Historically, the mainstay of treatment has been combination chemotherapy. More recently, a number of targeted therapies have been developed and are being studied with the goal of improving response rate and survival in patients with metastatic EGC. To date, the only targeted therapy which has been clinically approved is trastuzumab which targets the HER2/Neu oncogene. However, only a small group of patients with EGCs are HER2 amplified, and there are other important targets/pathways which play a role in the development of these cancers that are currently being studied. With the identification of these other clinically relevant pathways, it is anticipated that several other therapies will be approved in the future.

Epidermal growth factor receptor (EGFR) is overexpressed in high-grade dysplasia and adenocarcinoma of the esophagus and may represent a biomarker of histological progression in Barrett's esophagus (BE)

OBJECTIVES

The assessment of cancer risk in patients with Barrett's esophagus (BE) is currently fraught with difficulty. The current gold standard method of assessing cancer risk is histological assessment, with the appearance of high-grade dysplasia (HGD) as the key event monitored. Sampling error during endoscopy limits the usefulness of this approach, and there has been much recent interest in supplementing histological assessment with molecular markers, which may aid in patient stratification.

METHODS

No molecular marker has been yet validated to accurately correlate with esophageal histological progression. Here, we assessed the suitability of several membranous proteins as biomarkers by correlating their abundance with histological progression. In all, 107 patient samples, from 100 patients, were arranged on a tissue microarray (TMA) and represented the various stages of histological progression in BE. This TMA was probed with antibodies for eight receptor proteins (mostly membranous).

RESULTS

Epidermal growth factor receptor (EGFR) staining was found to be the most promising biomarker identified with clear increases in staining accompanying histological progression. Further, immunohistochemistry was performed using the full-tissue sections from BE, HGD, and adenocarcinoma tissues, which confirmed the stepwise increase in EGFR abundance. Using a robust H-score analysis, EGFR abundance was shown to increase 13-fold in the adenocarcinoma tissues compared to the BE tissues. EGFR was "overexpressed" in 35% of HGD specimens and 80% of adenocarcinoma specimens when using the H-score of the BE patients (plus 3 s.d.) as the threshold to define overexpression. EGFR staining was also noted to be higher in BE tissues adjacent to HGD/adenocarcinoma. Western blotting, although showing more EGFR protein in the adenocarcinomas compared to the BE tissue, was highly variable. EGFR overexpression was accompanied by aneuploidy (gain) of chromosome 7, plus amplification of the EGFR locus. Finally, the bile acid deoxycholic acid (DCA) (at neutral and acidic pH) and acid alone was capable of upregulating EGFR mRNA in vitro, and in the case of neutral pH DCA, this was NF-κB dependent.

CONCLUSIONS

EGFR is overexpressed during the histological progression in BE tissues and hence may be useful as a biomarker of histological progression. Furthermore, as EGFR is a membranous protein expressed on the luminal surface of the esophageal mucosa, it may also be a useful target for biopsy guidance during endoscopy.

Her-2/neu testing and therapy in gastroesophageal adenocarcinoma

Despite ongoing advances in the treatment of gastroesophageal cancer, prognosis remains poor. The best promise to improve this poor survival is provided by new targeted agents. Of these, human epidermal growth factor receptor 2 (HER2) is currently in the spotlight. In this review, we provide an overview of recent developments in HER2 testing and results of clinical trials targeting HER2 in gastroesophageal adenocarcinoma. Based on the encouraging ToGA trial findings it is now expected that routine HER2 testing will be included in the diagnostic work-up of patients with advanced gastric cancer. With regard to this testing, overexpression of the HER2 protein seems to possess the best predictive properties. However, HER2 immunohistochemistry (IHC) is subject to assay and interobserver variability, so standardization and internal and external proficiency testing is an absolute prerequisite, especially as the IHC scoring system in gastric cancer is different from that of breast cancer. Further study is needed to investigate the clinical meaning of the significant heterogeneity observed in both gene amplification and protein overexpression in gastroesophageal cancer. Highly effective therapies for gastroesophageal cancer can only be accomplished by a multi-targeted approach, considering crosstalk between pathways and continuing to optimize chemotherapy.

Esophageal adenocarcinoma: treatment modalities in the era of targeted therapy

Esophageal adenocarcinoma is an aggressive malignancy with a poor outcome, and its incidence continues to rise at an alarming rate. Current treatment strategies combining chemotherapy, radiation, and surgery are plagued with high rates of recurrence and metastasis. Multiple molecular pathways including the epidermal growth factor receptor, vascular endothelial growth factor, v-erb-b2 erythroblastic leukemia viral oncogene homolog (ERBB2), and Aurora kinase pathways are activated in many esophageal adenocarcinomas. In many cases, these pathways have critical roles in tumor progression. Research on the mechanisms by which these pathways contribute to disease progression has resulted in numerous biologic agents and small molecules with the potential to improve outcome. The promise of targeted therapy and personalized medicine in improving the clinical outcome is now closer than it has ever been.

The pathogenesis of Barrett's metaplasia and the progression to esophageal adenocarcinoma

The most important risk factor for the development of Barrett's esophagus is the reflux of both gastric and duodenal contents into the esophagus. The reason why Barrett's metaplasia develops only in a minority of patients suffering from gastroesophageal reflux disease remains unknown.The exact mechanism behind the transition of normal squamous epithelium into specialized columnar epithelium is also unclear. It is likely that stem cells are involved in this metaplastic change, as they are the only permanent residents of the epithelium. Several tumorigenic steps that lead to the underlying genetic instability, which is indispensable in the progression from columnar metaplasia to esophageal adenocarcinoma have been described. This review outlines the process of pathogenesis of Barrett's metaplasia and its progression to esophageal adenocarcinoma.

Esophagogastric cancer: targeted agents

Because of the poor prognosis for patients with locally advanced and metastatic esophageal, gastroesophageal junction and gastric cancers, increasing attention has focused on the integration of targeted agents into current therapies. The molecular targets of these agents include epidermal growth factor receptor (EGFR), vascular endothelial growth factor (VEGF) or its receptor, cyclooxygenase-2 (COX-2), mammalian target of rapamycin (mTOR) and components and regulators of the cell cycle. In this review article, we briefly discuss pre-clinical data and the rationale for targeting these pathways and summarize the results of clinical trials to-date, including completed and ongoing phase III evaluations.

Genetics in the pathogenesis of esophageal cancer: possible predictive and prognostic factors

INTRODUCTION

Esophageal adenocarcinoma is the most rapidly increasing cancer in Western countries. Like esophageal squamous-cell carcinoma, these tumors are often detected at an advanced stage, requiring a multimodal concept. Despite improvements in detection, surgical resection, and (neo-) adjuvant therapy, the overall survival of esophageal cancer remains lower than other solid tumors. In fact, just 30-40% of the patients with advanced esophageal cancer benefit from a neoadjuvant therapy. Therefore, predictive/prognostic markers are needed to allow tailored multimodality therapy with increased efficacy.

DISCUSSION

In recent years, there has been an exponential growth in our understanding of the cellular and molecular events associated with cell cycle regulation, programmed cell death, angiogenesis, and tumor growth. In this review, the classification of Hanahan and Weinberg is used concerning the six essential changes in carcinogenesis, i.e., the six hallmarks of cancer: (1) self-sufficiency in growth signals; (2) insensitivity to antigrowth signals; (3) avoidance of apoptosis; (4) limitless replicative potential; (5) sustained angiogenesis; and (6) tissue invasion and metastasis.

CONCLUSIONS

According to these six steps, this review provides an update of the most recent data about predictive/prognostic molecular markers in patients with esophageal cancer.

Pathology and pathobiology of the oesophageal carcinoma

Carcinoma of the oesophagus including carcinoma of gastro-oesophageal junction are rapidly increasing in incidence. During recent years there have been changes in the knowledge surrounding biology of the disease progression. Identification of dysplasia in mucosal biopsies is the most reliable pathologic indicator of an increased risk of development of squamous cell carcinoma and passes through the sequence of chronic esophagitis, low-grade and high-grade dysplasia and invasive carcinoma. Although Barrett's esophagus is a precursor to esophageal adenocarcinoma and have a well described sequence of carcinogenesis: the Barrett's metaplasia-dysplasia-adenocarcinoma sequence, not all patients with this disorder require intensive surveillance. The natural history of dysplasia is poorly understood, particularly in low-risk regions, and prospective follow-up studies are needed. Adjunctive methods to improve reproducibility, such as immunostaining for alpha-methylacyl-coenzyme A racemase (AMACR), show promise, but require confirmation in larger studies. In addition, several controversial methods such as detection of p16, p53, and DNA content abnormalities may help identify patients at particularly high risk for progression to cancer, but these techniques are not yet widely available for routine clinical application. More studies are needed to define other early nonmorphologic biomarkers for risk of squamous cell carcinoma. Recent evidence regarding the importance of several histopathologically derived prognostic factors, such as circumferential resection margin status and lymph node metastases are evaluated, including lymph node micrometastases and the sentinel node concept. With the rising use of multimodal treatments for oesophageal cancer it is important that the response of the tumour to this therapy can be carefully documented by histopathology.

The secretory phospholipase A2 gene is required for gastroesophageal reflux-related changes in murine esophagus

BACKGROUND

The initial response of esophageal mucosa to gastroduodenal reflux is inflammation and hyperplasia. Secretory phospholipase A(2) (sPLA(2)) is a known mediator of gut inflammation, and its levels are increased in Barrett's esophagus. We hypothesized that the sPLA(2) gene is required to produce esophageal mucosal hyperplasia in response to gastroduodenal reflux.

METHODS

C57BL/6 (n = 5) sPLA(2) (-/-) mice and C57BL/6( Cg-Tg(PLA2G2A)703N16 ) mice (n = 4) sPLA(2) (-/+) underwent a side-to-side surgical anastomosis between the duodenum and gastroesophageal junction (DGEA). Control animals [sPLA(2) (-/-) (n = 5), sPLA(2) (-/+) (n = 4)] underwent laparotomy with incision and repair of the esophagus. Tissue was harvested after 4 weeks, and H&E staining was performed to quantify esophageal mucosal thickness. Ki67 and sPLA(2) immunostaining were performed to quantitate differences in cell division and sPLA(2) expression.

RESULTS

Mice expressing human sPLA(2) had a 2.5-fold increase in thickness of the esophageal mucosa as compared to controls (p = 0.01). A 6.5-fold increase in proliferation (p = 0.02) and a twofold increase in sPLA(2) expression (p = 0.04) were demonstrated in animals exposed to gastroduodenal reflux.

CONCLUSIONS

The presence of sPLA(2) is necessary for early mucosal hyperplasia produced by exposure of the esophagus to gastroduodenal contents. sPLA(2) expression is upregulated by gastroduodenal reflux, strengthening its role as a critical mediator of early mucosal hyperplasia.

Feasibility of chemoradiotherapy for oesophageal cancer in elderly patients aged >or=75 years: a prospective, single-arm phase II study

BACKGROUND

The number of elderly patients with oesophageal cancer is expected to increase with the aging of the population and the rapidly increasing incidence of adenocarcinoma. Surgical resection is standard treatment for patients with localized disease considered fit for operation. However, elderly patients with oesophageal cancer are rarely referred for surgery. The aim of this prospective, single-arm, phase II study was to evaluate the feasibility and efficacy (tumour response) of chemoradiotherapy in the treatment of elderly patients with localized oesophageal cancer. Secondary endpoints were progression-free survival (PFS) and quality of life (QOL).

METHODS

The main study inclusion criteria were: patients aged >or=75 years; oesophageal cancer disease stage II-III; Charlson co-morbidity index score <or=4; Eastern Cooperative Oncology Group (ECOG) performance status 0-2; and weight loss <15%. The radiotherapy regimen consisted of 50 Gy over 5 weeks. Cisplatin 75 mg/m2 was given on days 1 and 21 of radiotherapy. Complete response was defined as disappearance of the tumour at endoscopy and/or at oesophagography and CT scan. Written informed consent was obtained from all patients. A three-step Fleming design was used to calculate the sample size.

RESULTS

Twenty-two patients were included in the study between March 2000 and June 2004; this sample size was sufficient to allow conclusions to be drawn from the study. The mean age of the patients was 79.4 years (range 75-89 years), 18 were male (81.8%), 15 had squamous cell carcinoma (68%) and 11 had stage IIA disease (50%). The mean Charlson co-morbidity index score was 1. All patients were compliant with the planned treatment, including doses and timing. During treatment, ECOG performance status remained stable during the first 3 weeks and worsened slightly over the last 2 weeks. Dysphagia remained stable. Five patients (22%) had transient grade 2 vomiting after the second cisplatin injection. No patient experienced nephrotoxic adverse effects and there were no toxicity-related deaths. Six weeks after treatment, 14 patients were in complete response (63.6%) and 8 patients (36.4%) had no treatment effect. The overall survival was 81.6% at 6 months and 62.4% at 1 year. The PFS at 1 year was 50%. Four patients (18.2%) were alive without disease from 2.6 to 5.5 years after treatment. In 14 evaluable patients, QOL 6 weeks after treatment was slightly altered by treatment.

CONCLUSIONS

The results of this prospective phase II study support the feasibility of chemoradiotherapy for oesophageal cancer in carefully selected elderly patients, with the potential for a curative effect.