Immunohistochemical analysis of nuclear survivin expression in esophageal squamous cell carcinoma

Excision repair cross-complementing group 1 (ERCC1) overexpression inhibits cell apoptosis and is associated with unfavorable prognosis of esophageal squamous cell carcinoma

Excision repair cross-complementing group 1 (ERCC1) functions as a nucleotide excision repair (NER) enzyme. Altered ERCC1 expression or function is closely associated with cancer development and progression. This study determined the association of ERCC1 expression with survivin expression, clinicopathological characteristics, and survival of esophageal squamous cell carcinoma (ESCC) patients after postoperative concurrent chemoradiotherapy.Tissue specimens from 102 resected ESCC patients were acquired for immunohistochemical analysis of ERCC1 and survivin protein expression.ERCC1 expression was detected in 62.7% of ESCC tissues and in 9.8% of normal squamous epithelium tissues (P < .01), while survivin expression was detected in 60.8% of ESCC tissues and in 19.6% of normal squamous epithelia (P < .01). ERCC1 overexpression associated with advanced tumor clinical stage and lymph node metastasis (P < .05), but not with tumor size, depth of invasion, or differentiation (P > .05). ERCC1 overexpression was also associated with survivin levels (r = 0.42, P < .01) and worse progression-free survival of ESCC patients after concurrent chemoradiotherapy. Multivariate analysis data revealed that ERCC1 and survivin protein expression were independent predictors of overall survival of ESCC patients after chemotherapy and/or radiotherapy (P < .05).ERCC1 overexpression is an important phenotype that is associated with ESCC lymph node metastasis and advanced tumor clinical stages. ERCC1 expression may also inhibit ESCC cell apoptosis via regulating survivin expression, and ERCC1 and survivin overexpression are independent predictors of prognosis for ESCC patients who receive chemotherapy and/or radiotherapy.

Clinicopathological and functional implications of the inhibitor of apoptosis proteins survivin and XIAP in esophageal cancer

Based on their overexpression and important roles in progression and therapy-resistance in malignant diseases, the inhibitor of apoptosis protein family (IAP) members, survivin and X-linked inhibitor of apoptosis protein (XIAP), represent attractive candidates for targeted therapy. The present study investigated the prognostic and biological relevance of survivin and XIAP in esophageal squamous-cell carcinoma (ESCC) and esophageal adenocarcinoma (EAC). Survivin and XIAP expression was analyzed by immunohistochemistry using tissue microarrays containing 120 ESCC and 90 EAC samples as well as the corresponding non-neoplastic esophageal mucosa samples. IAP expression levels were then correlated to clinicopathological parameters and overall survival to identify any associations. In addition, esophageal cancer cell lines were treated with the survivin inhibitor YM155, and the XIAP inhibitors Birinapant and GDC-0152 in vitro. Survivin and XIAP expression were significantly increased in EAC and ESCC when compared with tumor-adjacent mucosa. In patients with ESCC XIAP expression was associated with female gender and advanced tumor stages, and nuclear survivin expression was associated with poor grading. High XIAP expression was identified as an independent negative prognostic marker in ESCC. By contrast, XIAP inhibitors did not affect cancer cell viability in vitro, and the small molecule survivin inhibitor YM155 significantly reduced cell viability and proliferation in esophageal cancer cell lines. Western blot analysis revealed a dose dependent decrease of survivin accompanied by an increased poly (adenosine diphosphate-ribose) polymerase cleavage following YM155 treatment. These findings underline the potential role of survivin and XIAP in the oncogenesis of esophageal cancer and provide a rationale for future clinical studies investigating the therapeutic efficacy of IAP directed therapies in patients with esophageal cancer.

Inducing death in tumor cells: roles of the inhibitor of apoptosis proteins

The heterogeneous group of diseases collectively termed cancer results not just from aberrant cellular proliferation but also from a lack of accompanying homeostatic cell death. Indeed, cancer cells regularly acquire resistance to programmed cell death, or apoptosis, which not only supports cancer progression but also leads to resistance to therapeutic agents. Thus, various approaches have been undertaken in order to induce apoptosis in tumor cells for therapeutic purposes. Here, we will focus our discussion on agents that directly affect the apoptotic machinery itself rather than on drugs that induce apoptosis in tumor cells indirectly, such as by DNA damage or kinase dependency inhibition. As the roles of the Bcl-2 family have been extensively studied and reviewed recently, we will focus in this review specifically on the inhibitor of apoptosis protein (IAP) family. IAPs are a disparate group of proteins that all contain a baculovirus IAP repeat domain, which is important for the inhibition of apoptosis in some, but not all, family members. We describe each of the family members with respect to their structural and functional similarities and differences and their respective roles in cancer. Finally, we also review the current state of IAPs as targets for anti-cancer therapeutics and discuss the current clinical state of IAP antagonists.

Survivin over-expression is correlated with a poor prognosis in esophageal cancer patients

BACKGROUND

The prognostic role of survivin in esophageal cancer (EC) remains controversial. This meta-analysis aimed to clarify the association of survivin with survival in EC patients.

METHODS

Relevant studies published up to November 2014 were identified using PubMed and Embase. Only studies in which survivin was detected through immunohistochemical staining were included. STATA 12.0 was used in this meta-analysis.

RESULTS

A total of 9 studies, which comprised 610 patients, were included in the meta-analysis. The combined hazard ratio (HR) of 1.76 (95% CI, 1.40-2.21; P<0.001) suggests that survivin overexpression in EC patients was significantly associated with poor overall survival. Moreover, the results showed a significant relationship between overall survival and survivin expression was also displayed in studies with a non-Asian country (HR, 1.75; 95% CI, 1.30-2.35), patient number ≥ 50 (HR, 1.86; 95% CI, 1.57-2.20), the cut-off level ≥ 5% (HR, 1.43; 95% CI, 0.94-2.17) and the esophageal squamous cell carcinoma (HR, 1.82; 95% CI, 1.43-2.30). However, combined odds ratio of survivin indicated that survivin overexpression has no correlation with stage, grade of differentiation, lymph node status, depth of invasion and distant metastasis of EC (P>0.05).

CONCLUSION

Survivin overexpression is associated with poor prognosis in EC patients.

Small-molecule survivin inhibitor YM155 enhances radiosensitization in esophageal squamous cell carcinoma by the abrogation of G2 checkpoint and suppression of homologous recombination repair

Background

Survivin is overexpressed in cancer cells and plays a crucial role in apoptosis evasion. YM155, a small-molecule inhibitor of survivin, could enhance the cytotoxicity of various DNA-damaging agents. Here, we evaluated the radiosensitizaion potential of YM155 in human esophageal squamous cell carcinoma (ESCC).

Methods

Cell viability was determined by CCK8 assay. The radiosensitization effect of YM155 was evaluated by clonogenic survival and progression of tumor xenograft. Cell cycle progression was determined by flow cytometric analysis. Radiation-induced DNA double strand break (DSB) and homologous recombination repair (HRR) were detected by the staining of γ-H2AX and RAD51, respectively. Expression of survivin and cell cycle regulators was detected by Western blot analysis.

Results

YM155 induced radiosensitization in ESCC cell lines Eca109 and TE13, associated with the abrogation of radiation induced G₂/M checkpoint, impaired Rad51 focus formation, and the prolongation of γ-H2AX signaling. G₂/M transition markers, including the activation of cyclinB1/Cdc2 kinase and the suppression of Cdc2 Thr14/Tyr15 phosphorylation were induced by YM155 in irradiated cells. The combination of YM155 plus irradiation delayed the growth of ESCC tumor xenografts to a greater extent compared with either treatment modality alone.

Conclusions

Our findings suggest that the abrogation of G₂ checkpoint and the inhibition of HRR contribute to radiosensitization by YM155 in ESCC cells.

Systematic review and meta-analysis of tumor biomarkers in predicting prognosis in esophageal cancer

BACKGROUND

Esophageal cancer (EC) is a frequently occurring cancer with poor prognosis despite combined therapeutic strategies. Many biomarkers have been proposed as predictors of adverse events. We sought to assess the prognostic value of biomarkers in predicting the overall survival of esophageal cancer and to help guide personalized cancer treatment to give patients the best chance at remission.

METHODS

We conducted a systematic review and meta-analysis of the published literature to summarize evidence for the discriminatory ability of prognostic biomarkers for esophageal cancer. Relevant literature was identified using the PubMed database on April 11, 2012, and conformed to the REMARK criteria. The primary endpoint was overall survival and data were synthesized with hazard ratios (HRs).

RESULTS

We included 109 studies, exploring 13 different biomarkers, which were subjected to quantitative meta-analysis. Promising markers that emerged for the prediction of overall survival in esophageal squamous cell cancer included VEGF (18 eligible studies, n=1476, HR=1.85, 95% CI, 1.55-2.21), cyclin D1 (12 eligible studies, n=1476, HR=1.82, 95% CI, 1.50-2.20), Ki-67 (3 eligible studies, n=308, HR=1.11, 95% CI, 0.70-1.78) and squamous cell carcinoma antigen (5 eligible studies, n=700, HR=1.28, 95% CI, 0.97-1.69); prognostic markers for esophageal adenocarcinoma included COX-2 (2 eligible studies, n=235, HR=3.06, 95% CI, 2.01-4.65) and HER-2 (3 eligible studies, n=291, HR=2.15, 95% CI, 1.39-3.33); prognostic markers for uncategorized ECs included p21 (9 eligible studies, n=858, HR=1.27, 95% CI, 0.75-2.16), p53 (31 eligible studies, n=2851, HR=1.34, 95% CI, 1.21-1.48), CRP (8 eligible studies, n=1382, HR=2.65, 95% CI, 1.64-4.27) and hemoglobin (5 eligible studies, n=544, HR=0.91, 95% CI, 0.83-1.00).

CONCLUSIONS

Although some modest bias cannot be excluded, this review supports the involvement of biomarkers to be associated with EC overall survival.

OCT4 positively regulates Survivin expression to promote cancer cell proliferation and leads to poor prognosis in esophageal squamous cell carcinoma

Background

OCT4 and Survivin are important factors for cancer cell proliferation, renewal and dedifferentiation, and correlate with resistance to radiotherapy and chemotherapy in most human cancers, but their regulatory mechanisms are not well known.

Methodology/Principal Findings

In this study, 50 patients with esophageal squamous cell carcinoma (ESCC) were retrospectively analyzed. OCT4 was expressed in 13 cases (26%), and survivin was positively expressed in 31 cases (62%), examined by immunochemistry. OCT4 was found to be an independent predictive factor for median survival time, and the patients from the subgroup with both high expression of OCT4 and Survivin had the worst prognosis investigated by log-rank test. To further explore the molecular regulatory mechanism between OCT4 and Survivin, we constructed the specific small hairpin RNA (shRNA)-expressing vectors targeting OCT4 or/and Survivin and manipulated the expression of OCT4 and Survivin. By Western blotting and RT-PCR, we found that OCT4 could up-regulate Survivin expression in the esophageal cancer cell lines Eca109 and TE1. Simultaneously knockdown of OCT4 and Survivin expression induced cell apoptosis and G2-phase decrease of cell cycle by flow cytometry, and finally exerted an enhanced anti-proliferation potency in Eca109 and TE1 cell lines by MTT assay.

Conclusions

This study shows that OCT4 and Survivin expression were correlated with poor survival in patients with ESCC. OCT4 and Survivin may be regarded as targets in ESCC biotherapy.

Nuclear, but not cytoplasmic, localization of survivin as a negative prognostic factor for survival in upper urinary tract urothelial carcinoma

Survivin, a member of the inhibitor of apoptosis protein gene family, inhibits apoptosis and promotes mitosis. We determined whether nuclear or cytoplasmic localization of survivin could predict survival of patients with upper urinary tract urothelial carcinoma (UUTUC). Immunohistochemical staining for survivin was carried out on archival specimens from 125 consecutive patients with UUTUC who underwent radical nephroureterectomy. Nuclear and cytoplasmic staining of survivin was scored and compared with clinicopathologic features and cancer-specific survival (CSS). Nuclear expression of survivin was significantly correlated with tumor grade (p < 0.001), lymphovascular invasion (p = 0.022) and poor survival with an estimated 5-year CSS probability of 54 % for tumors with nuclear expression of survivin vs. 73 % for those without nuclear expression of survivin (hazard ratio = 2.19; 95 % confidence interval = 1.02-4.70; p = 0.043). The 5-year cancer-specific survival rates of patients with cytoplasmic survivin-negative and -positive tumors were 66 and 67 %, respectively. There was no difference in survival between patients with cytoplasmic survivin-negative tumors and those with cytoplasmic survivin-positive tumors. Using univariate analysis, nuclear survivin expression, tumor grade, pathological T stage, pathological N stage, and lymphovascular invasion were the predictive variables for CSS. In contrast, cytoplasmic survivin expression had no prognostic relevance. These data suggest that nuclear accumulation of survivin represents biologic aggressiveness and that nuclear survivin is a negative prognostic marker in patients with resected UUTUC.

Clinicopathological and prognostic significance of survivin over-expression in patients with esophageal squamous cell carcinoma: a meta-analysis

Background

The prognostic significance of survivin for survival of patients with esophageal squamous cell carcinoma (ESCC) remains controversial. Thus, meta-analysis of the literatures was performed in order to demonstrate its expression impact on ESCC clinicopathological features and prognosis.

Methodology

Relevant literatures were searched using PubMed, EMBASE and Medline Databases. Revman5.0 software was used to pool eligible studies and summary hazard ratio (HR). Correlation between survivin expression and clinicopathological features of ESCC was analyzed.

Principal Findings

Final analysis of 523 patients from 7 eligible studies was performed. Combined HR of survivin location in nuclei suggested that survivin expression has an unfavorable impact on ESCC patients' survival (n = 277 in 3 studies; HR = 1.89, 95% CI: 1.45–2.96; Z = 4.69; P<0.0001). Nevertheless, combined HR of survivin location in cytoplasm displayed that survivin expression has no significance for prognosis of ESCC patients (n = 113 in 2 studies; HR = 0.96, 95% CI: 0.96–5.69; Z = 0.04; P = 0.97); Combined odds ratio (OR) of survivin location in cytoplasm indicated that survivin expression is associated with ESCC advanced stage (n = 113 in 2 studies; OR = 0.36, 95% CI: 0.14–0.93; Z = 2.10; P = 0.04). Whereas, combined OR of survivin location in nuclei exhibited that survivin over-expression has no correlation with cell differentiation grade, lymph node status, depth of invasion, stage, and metastasis of ESCC.

Conclusions

This study showed that survivin expression detected by immunohistochemistry seems to be associated with a worse prognosis of ESCC patients. Survivin subcellular location may be an important factor impacting on ESCC development. Larger prospective studies should be performed to evaluate the status of survivin in predicting prognosis of patients with ESCC.

Clinical correlation of nuclear survivin in esophageal squamous cell carcinoma

To examine the correlation of survivin (both total and nuclear survivin) with clinicopathological parameters of esophageal squamous cell carcinoma (ESCC) patients. Tumors and non-tumor tissues near the proximal resection margins were resected from ESCC patients undergone esophagectomy. Quantitative polymerase chain reaction (qPCR) was performed to detect survivin mRNA expression level in the 10 paired tumor and adjacent non-tumor tissues. To confirm with the clinical situation, survivin mRNA and protein expression were measured by qPCR and immunoblot, respectively, in 5 ESCC cell lines and a non-neoplastic esophageal epithelial cell line. Immunohistochemistry was employed to reveal the cellular localization of survivin in tumor tissues isolated from the 64 ESCC patients undergone surgery alone. Up-regulation of survivin mRNA and protein was found in 5 ESCC lines (HKESC-1, HKESC-2, HKESC-3, HKESC-4, and SLMT-1) when compared to a non-neoplastic esophageal epithelial cell line NE-1. In particular, HKESC-3, HKESC-4, and SLMT-1 cells demonstrated ~50-fold increase in survivin mRNA. High level of survivin mRNA in tumor tissues when compared to non-tumor tissues was found in 70 % (7 of 10) of clinical cases. The increase in expression ranged from ~twofold to ~16-fold. Immunohistochemistry results showed that survivin was found at the cell nuclei in all specimens examined. Nuclear expression of survivin was inversely associated with the likelihood of developing nodal metastasis (p = 0.021) and significantly associated with early-stage ESCC (p = 0.039). Nuclear survivin could serve as a marker for indicating disease status in ESCC patients.

Survivin expression quantified by Image Pro-Plus compared with visual assessment

Over the past decades, immunohistochemistry has gained significance and already taken a crucial position in diagnosis of diseases and prognosis of patients. However, manual interpretation of immunohistochemistry and reproducibility of the scoring systems can be highly subjective. In the article, the immunohistochemical staining of survivin in 98 rectal cancers was analyzed by using Image Pro-Plus (IPP) [3 parameters: density mean, area sum, and integrated optical density (IOD)] and the results were compared with visual assessment (2 parameters: intensity and percentage). The correlations between the 2 methods were examined, significant correlations were observed between density mean and staining intensity (Spearman correlation coefficient, rs=0.806, P<0.001), IOD and staining intensity (rs=0.914, P<0.001), area sum and staining percentage (rs=0.883, P<0.001), IOD and staining percentage (rs=0.884, P<0.001). There was no significant difference between survivin expression and clinicopathologic variables (P>0.05) by visual assessment. However, by IPP analysis, both the density mean and IOD were higher in better-differentiated cancers than in worse differentiated ones (P=0.02 and 0.03). There was a substantial agreement between the 2 methods. Density mean and IOD of IPP were representative parameters to assess the immunostaining quantification, and increased sensitivity in scoring and provided a more reliable and reproducible analysis of protein expression, especially, more information of the protein expression in relation to clinicopathologic variables can be provided by IPP analysis.

Detection of survivin-expressing circulating cancer cells in the peripheral blood of patients with esophageal squamous cell carcinoma and its clinical significance

We previously demonstrated that the detection of circulating cancer cells (CCC) expressing survivin mRNA could provide valuable information for predicting recurrence in patients with breast, lung, gastric and colorectal carcinoma. The purpose of this study is to investigate whether the detection of survivin-expressing CCC in the peripheral blood is also useful for predicting recurrence in patients with esophageal squamous cell carcinoma (ESCC). Blood samples obtained from 108 ESCC patients and 75 healthy volunteers were quantitatively investigated by a technique that detected reverse transcription-polymerase chain reaction products based on a hybridization-enzyme linked immunosorbent essay. Not all of the patients were available for the follow-up study. Only 48 patients who were treated with similar adjuvant therapy regimens were available and followed-up for 33 months after the initial assay test. Survivin-expressing CCC were detected in 51 (47.2%) patients. The presence of survivin-expressing CCC was found to be significantly associated with depth of invasion, vascular invasion, nodal status, and disease stages (P = 0.032, 0.019, 0.018, and 0.001, respectively). During the follow-up period, patients who had positive survivin expressions had a higher relapse rate and a shorter survival time than those who had negative survivin expressions (P = 0.002 and 0.016, respectively). Examination of survivin-expressing CCC could provide valuable information in the prediction of haematogenous recurrence as well as in the prognosis of ESCC.

Cortactin, fascin, and survivin expression associated with clinicopathological parameters in esophageal squamous cell carcinoma

Cortactin, fascin, and survivin have been documented in several human cancers and play important roles in tumor progression. We collected 57 surgical specimens, including esophageal squamous cell carcinomas (SqCC; 7 well-differentiated, 15 moderately differentiated, and 24 poorly differentiated), 3 dysplasias, and 8 normal esophageal tissues. Tissue microarrays were constructed and the immunostaining scores for cortactin, fascin, and survivin were assessed. In 46 SqCC specimens, we examined the relationship between the expression of three biomarkers and tumor differentiation or clinical parameters. Higher immunostaining scores for cortactin, fascin, and survivin correlated positively with tumor differentiation of esophageal SqCC. Univariate survival analysis showed significantly worse prognosis in patients with high scores of cortactin (>or=290), fascin (>or=245), and survivin (score >or= 175), poor differentiation, T4 stage, positive for lymph node metastasis, and positive for distant metastasis. In multivariate survival analysis, high scores of survivin (>or=175) and poor differentiation were independent risk factors for worse prognosis. Our results demonstrated that higher expression of survivin may be related to tumor progression and it is an independent risk factor for poor survival time of esophageal SqCC. Survivin may be a good biomarker to be applied in clinic to predict the prognosis of esophageal SqCC.

Relationship between survivin expression and chemoradiotherapy response in esophageal squamous cell carcinoma

AIM: To investigate the relationship between survivin expression and the chemoradiotherapy (CRT) response in esophageal squamous cell carcinoma (ESCC).

METHODS: The expression of survivin in 112 cases of ESCC tissues were detected using immunohistochemistry (IHC). Relation between survivin expression (including nucleus and cytoplasm expression) and short-term response as well as its relationship with downstage rate of CRT were analyzed retrospectively.

RESULTS: Survivin expression was noted in ESCC cytoplasm and nucleus with 65.2% and 67.8% expression rates respectively. Survivin expressed in cytoplasm was not correlated to short-term response, but the response of patients with nuclear survivin expression was significantly lower than that with nuclear negative expression (46.1% vs 80.6%, P = 0.026). In neoadjuvant CRT group, downstage rates of patients with positive and negative nuclear survivin were 7/17 and 4/4 respectively.

CONCLUSION: Assessment of nuclear survivin could provide additional information to identify ESCC patients with poor chances of response to CRT and candidates for more individualized treatment.

Protein alterations in ESCC and clinical implications: a review

Esophageal squamous cell carcinoma (ESCC) is the predominant histological subtype of esophageal cancer in Asia, characterized by high incidence and mortality rate. Although significant progress has been made in surgery and adjuvant chemoradiotherapy, the prognosis of the patients with this cancer still remains poor. Investigation into protein alterations that occurred in tumors can provide clues to discover new biomarkers for improving diagnosis and guiding targeted therapy. Hundreds of papers have appeared over the past several decades concerning protein alterations in ESCC. This review summarizes all the dysregulated proteins investigated in the disease from 187 published papers and analyzes their contributions to tumor development and progression. We document protein alterations associated with tumor metastasis and the transition from normal esophageal epithelia to dysplasia in order to reveal the most useful markers for prediction of clinical outcome, early detection, and identification of high-risk patients for targeted therapies. In particular, we discuss the largest and most rigorous studies on prognostic implications of proteins in ESCC, in which cyclin D1, p53, E-cadherin and VEGF appeared to have the strongest evidence as independent predictors of patient outcome.

Failure in downregulation of intratumoral survivin expression following neoadjuvant chemoradiation in esophageal cancer

Introduction: Neoadjuvant multimodality treatment is frequently applied to improve the poor prognosis associated with locally advanced esophageal cancer. However, only patients with a major histopathologic response to neoadjuvant therapy will have a significant survival benefit. Predictive markers to allow individualization of multimodality treatment could be very helpful. We aimed to examine the association of survivin protein expression, an inhibitor of apoptosis, with histopathologic response to neoadjuvant chemoradiation and prognosis in patients with esophageal cancer. Patients & methods: A total of 59 patients with esophageal cancer (clinical tumor stage 2–4, Nx, M0) received neoadjuvant chemoradiation followed by transthoracic en bloc esophagectomy. Histomorphologic regression was defined as major response when resected specimens contained less than 10% vital tumor cells. Intratumoral survivin expression was determined by immunohistochemistry in pretherapeutic biopsies and post-therapeutic resection specimens and correlated with clinicopathologic parameters. Results: The pretherapeutic intratumoral survivin protein expression was not associated with any clinicopathologic factor. Survivin protein expression decreased significantly during neoadjuvant therapy, showing lower levels in post-therapeutic tumor samples (p < 0.01). Elevated postoperative survivin levels were significantly associated with a higher pathologic tumor stage after neoadjuvant therapy (ypT) category (p < 0.01), a poorer histopathologic response (p < 0.01) and a shorter overall survival (p < 0.028). Conclusion: Intratumoral survivin protein expression was significantly downregulated during neoadjuvant therapy of esophageal cancers. Elevated survivin levels after preoperative therapy were significantly associated with a minor histopathologic response and prognosis. Therefore, failure in downregulation of intratumoral survivin expression following neoadjuvant chemoradiation in esophageal cancer needs therapeutic strategies to reduce survivin expression or block survivin-mediated pathways to increase the histopathologic response rate and prognosis.

Novel targeted therapies for advanced esophageal cancer

Esophageal cancer is highly aggressive and is the sixth leading cause of cancer death worldwide. Recent advances in multimodality chemoradiotherapy and surgery has improved survival in patients with loco-regional disease, but most patients with advanced stage esophageal cancer have a poor prognosis. Elucidation of the processes involved in esophageal carcinogenesis has identified a number of promising novel targets for therapy. This review focuses on the current status of targeted therapies with potential application to the treatment of advanced esophageal and gastroesophageal junction cancer. The future challenge is to confirm the efficacy of these targeted agents in appropriately selected esophageal cancer patients, and successfully integrate these agents into effective therapies for all stages and subtypes of disease.