Protein kinase D1 mRNA level may predict cancer‐specific survival in heavy smokers with esophageal squamous cell cancers

Protein kinase D1 (PRKD1) is a kinase that regulates various pathways, which involve in cell proliferation, apoptosis, cell adhesion and invasion. Although PRKD1 expression has been observed in many cancers, its role in esophageal squamous cell cancer (ESCC) has not been well reported. As its dysregulation in cancers is organ specific, we sought to investigate the potential role of PRKD1 in the progression of ESCC. Samples were collected from 178 patients with completely resected ESCCs at Sun Yat‐sen University Cancer Center, including 47 pairs of tumorous and non‐tumorous tissues. PRKD1 mRNA expression was investigated by quantitative real‐time polymerase chain reaction. Receiver operating characteristic (ROC) curve analysis was used to search for a feasible cut‐off point of PRKD1 mRNA levels for predicting cancer‐specific survival. Kaplan–Meier and multivariate Cox regression analysis were used to assess the prognostic value of PRKD1 mRNA level in ESCC patients. In result, upregulation of PRKD1 mRNA was detected in 55.3% (26/47) of ESCC tissues compared with paired non‐tumorous ones (P = 0.011). ROC analysis indicated 3.28 as a cut‐off point, and thus 72 and 106 tumors with low and high PRKD1 mRNA expression were categorized. High‐PRKD1 mRNA expression in tumors appeared with more frequency in heavy smokers (P = 0.002) and patients with advanced pathological T category (P = 0.034). Kaplan–Meier analysis indicated that patients with low‐PRKD1 mRNA had a longer cancer‐specific survival than the ones with high‐PRKD1 level (P = 0.044). Multivariate analysis showed that tumorous PRKD1 mRNA expression was an independent prognostic factor (hazard ratio: 1.538, 95% confidence interval: 1.018–2.323, P = 0.041) in resected ESCC. Subgroup analysis revealed that the discernibility of PRKD1 mRNA level on ESCC outcomes was only pronounced in heavy smokers (P = 0.002), but not in non‐heavy smokers (P = 0.870). PRKD1 might play a potential oncogenic role in ESCC. It might be an independent biomarker to predict prognosis in heavy smokers with ESCC.     

Original article: Upregulation of caspase‐3 expression in esophageal cancer correlates with favorable prognosis: an immunohistochemical study from a high incidence area in northern China

Caspase‐3 plays an important role as the key effector during apoptosis, but there are very few studies of caspase‐3 in esophageal squamous cell carcinoma (ESCC). The purpose of this study was to investigate the expression and prognostic significance of caspase‐3 in ESCC from Linzhou City, a high incidence area in northern China. All 64 patients underwent esophagectomy for ESCC between January 2002 and December were enrolled in this study. Caspase‐3 expression was assessed by immunohistochemistry (IHC) in primary ESCC and paired normal esophageal epithelium. The positive rate of caspase‐3 expression was higher in ESCC than in normal esophageal epithelium (79.7% vs. 50.0%, Chi‐square = 12.372, P= 0.001). Caspase‐3 expression was correlated with tumor cell differentiation (Phi = 0.717, P < 0.001), tumor infiltration depth (Phi =?0.334, P= 0.008), and pathologic TNM (pTNM) staging (rs =?0.268, P= 0.032). Patients in caspase‐3 positive group had a significantly better 5‐year overall survival than those in the negative group (77.4% vs. 35.9%, χ²= 7.344, P= 0.007). Our results showed that caspase‐3 expression was upregulated in ESCC compared with normal esophageal epithelium in population of Chinese high incidence area, and patients with caspase‐3 positive expression had better prognosis. Therefore, caspase‐3 immunostaining could be a simple and useful tool for predicting survival in ESCC patients.     

Expression of breast cancer anti‐estrogen resistance 1 in relation to vascular endothelial growth factor,p53, and prognosis in esophageal squamous cell cancer

The purpose of this study was to clarify the role of breast cancer anti‐estrogen resistance 1 (BCAR1) expression in relation to vascular endothelial growth factor (VEGF), p53, and proliferation in esophageal squamous cell cancer (ESCC). Expression of BCAR1, VEGF, p53, and the ki‐67 proliferative index were examined by tissue microarray and immunohistochemistry in 106 specimens with ESCC and matched adjacent normal tissues. Among them, 40 cases were simultaneously examined by Western blot. Both Western blot and immunohistochemistry showed that BCAR1 expression was substantially higher in ESCC than in adjacent normal tissues (P < 0.001). BCAR1 expression was significantly connected with degree of tumor differentiation, with poorly differentiated tumors showing higher BCAR1 expression (P < 0.001). BCAR1 expression was significantly and positively correlated with VEGF and p53 expression levels (r= 0.541, P < 0.001; r= 0.374; P < 0.001) but not proliferative index (r= 0.44; P= 0.066). Additionally, a significant relationship was also observed between VEGF and p53 (r= 0.321; P= 0.001). Kaplan–Meier survival analysis revealed that patients with high BCAR1 expression had significantly shorter survival times than those with low BCAR1 expression levels (median survival 40 months vs. 27 months, P= 0.09). Multivariate analysis also revealed that levels of BCAR1 expression (hazard ratio 2.250, P= 0.015) was a significant and independent prognostic indicator. High expression of BCAR1 is associated with elevated VEGF and p53 expression levels, as well as poor prognosis in ESCC. Therefore, BCAR1 may be a potential candidate for predicting prognosis and a new therapy target for ESCC.     

Expression of klotho and β‐catenin in esophageal squamous cell carcinoma,and their clinicopathological and prognostic significance

Esophageal carcinoma is one of the most common types of cancers in the world; the molecular mechanism underlying its tumorigenesis is still not well understood. This study was aimed at investigating the expression of klotho and β‐catenin in patients with esophageal squamous cell carcinoma (ESCC) and analyzing their association with clinicopathological variables and their effects on prognosis. The expression patterns of klotho and β‐catenin were determined by tissue microarray and immunohistochemical technique in ESCC and normal tissues, and their correlations with clinicopathological characteristics were investigated using univariate and multivariate analysis. The serum klotho levels in 40 ESCC patients and controls were measured by sandwich enzyme‐linked immunosorbent assay system (ELISA). The expression level of klotho was significantly lower in ESCC than in the adjacent noncancerous tissues (30 vs. 50%, P < 0.000), and the protein level was negative correlated with clinical staging, histological grade, lymph node metastasis, and invasion depth (P < 0.05). Whereas, the expression of β‐catenin was much higher in ESCC than their corresponding normal mucosa tissues (78.3 vs. 11.5%, P < 0.000), and the level of protein correlated only with histological grade and invasion depth (P < 0.05). Correlation analysis showed the expression level of klotho inversely correlated with that of β‐catenin (r = ?0.214, P < 0.01). Patients with klotho‐positive tumors had longer survival than those with klotho‐negative tumors (P < 0.01). Cox proportional hazards model analysis demonstrated that positive expression of klotho was an important factor indicating good prognosis (hazard ratio, 0.371; 95% confidence interval, 0.201–0.685; P < 0.01). ELISA showed that the level of serum klotho was markedly higher (461.50 ± 43.30 pg/mL) than control group (239.37 ± 20.65 pg/mL) (P < 0.001). Receiver operating characteristic analysis gave a cut‐off value of 327.031 of serum klotho with a sensitivity of 81.3% and specificity of 81.2% (P < 0.000). Our present study demonstrated for the first time that klotho might be a novel biomarker candidate for predicting progression and prognosis in patients with ESCC.     

Expression and prognostic relevance of p21WAF1 in stage III esophageal squamous cell carcinoma

The prognostic effect of p21^WAF1 expression on esophageal squamous cell carcinoma patients is controversial. Further clarifying the effect of this protein is beneficial for optimizing the patient outcomes. In the current study, we investigated the expression of p21^WAF1 protein in 189 specimens of stage III ESCC by immunohistochemistry. As shown by the Kaplan–Meier curve, the overall survival rate of the positive‐expression group was significantly higher than that of the negative‐expression group (P < 0.05). No significant correlation was observed between p21^WAF1 expression and clinicopathological parameters in terms of gender, age, tumor location, tumor grade, pathological stage, and number of regional lymph node metastases (P > 0.05). We concluded that p21^WAF1 played an intricate role in the tumorigenesis and development of ESCC. p21^WAF1 could serve as a positive prognostic predictor for stage III ESCC patients.     

Clinical effect of E‐series of prostaglandin receptor 2 and epidermal growth factor receptor signal pathways in the development of esophageal squamous cell carcinoma

Signal pathways mediated by epidermal growth factor receptor (EGFR) and E‐series of prostaglandin receptors (EPs) are closely correlated to the pathogenesis of tumor. This experiment was designed to investigate the expression and clinical significance of EP2 and EGFR in esophageal squamous cell carcinoma (ESCC). Tissue samples were collected reterospectively from 87 patients with ESCC (first diagnosed). The patients were followed up for 5 years after radical surgery. The expression of EP‐2 and EGFR were examined by tissue chip technology and immunohistochemistry methods. Clinicopathological and prognostic impact were evaluated. Overexpression of EGFR and EP‐2 was more observed in ESCC than the control group (58.6% vs. 13.9%; 52.9% vs. 4.88%, P < 0.001, respectively); which correlated with tumor infiltration depth, lymph node metastasis, and tumor‐lymph node‐metastasis staging. Both the EP‐2 and EGFR overexpression were detected in 39 specimens and exhibited the positive correlation (P < 0.001, r = 0.404). Overexpression of EP2 and EGFR exhibited significant correlation with worse 5‐year overall survival than those with negative result (17.6% vs. 27.8%, P = 0.011; 10.9% vs. 34.1%, P < 0.001, respectively). Cox proportional hazard model showed that the T‐staging, lymph node metastasis, and EGFR overexpression were the independent risk factors of the prognosis. The present study exhibited that the overexpression of EP2 and EGFR in ESCC tissues might play an important role in carcinogenesis and the progression of ESCC.     

Association of mu‐opioid receptor expression with lymph node metastasis in esophageal squamous cell carcinoma

The mu‐opioid receptor (MOR), a membrane‐bound G protein‐coupled receptor, is the main target for opioids in the nervous system. MOR1 has been found in several types of cancer cells and reported to be involved in tumor progression and metastasis. However, the expression and clinical significance of MOR1 in esophageal squamous cell carcinoma (ESCC) remain unclear. In our study, the expression of MOR1 was confirmed in ESCC cell lines (KYSE180, KYSE150, and EC109) by Western blot. MOR1 was also detected on tissue microarrays of ESCC samples in 239 cases using immunohistochemical staining. We found that MOR1 was mainly located in the cytoplasm and occasionally occurred in the membrane or nucleus of ESCC cells. Moreover, results indicated that MOR1 expression in the cytoplasm was associated with lymph node metastasis (R = 0.164, P = 0.008, Kendall's tau‐b‐test). No more associations were found between MOR1 expression status and other clinical parameters. However, no statistical significant differences were found between MOR1 expression in the cytoplasm, nucleus/membrane, and the overall survival of ESCC patients (P = 0.848; P = 0.167; P = 0.428, respectively, log‐rank test). Our results suggest that the cytoplasmic MOR1 may be a high‐risk factor for lymph node metastasis of ESCC patients. We also hypothesize that MOR1 agonists used in ESCC patients should be prudent, and opioid receptor antagonists may be novel therapeutic drugs for ESCC patients.     

Original article: The expression of CFL1 and N‐WASP in esophageal squamous cell carcinoma and its correlation with clinicopathological features

Cofilin1 (CFL1) is an actin‐modulating protein, which belongs to the ADF/Cofilin family. Neural Wiskott–Aldrich syndrome protein (N‐WASP) is the key regulator of the actin cytoskeleton, a member of Wiskott‐Aldrich syndrome protein family. They have been suggested to be involved in cancer cell invasion and metastasis. In this study, the expression patterns of CFL1 and N‐WASP in normal esophageal mucosa and esophageal squamous cell carcinoma (ESCC) and their correlation with clinical characteristics were investigated. Immunohistochemical staining showed that CFL1 was expressed in nuclear and cytoplasm of cancer cells. However, N‐WASP was mainly found in the cytoplasm of the cancer cells. There were significant evidences that proved that CFL1 is correlated with clinicopathological factors in ESCC, such as infiltration depth, lymph node metastasis and pathological staging (P < 0.05). It is also proved that N‐WASP is related to lymph node metastasis and pathological staging in ESCC (P < 0.05). Kaplan–Meier analysis showed that there was no correlation between CFL1 and N‐WASP protein expression and survival (P > 0.05). Moreover, the mRNA expression of CFL1 and N‐WASP was detected by quantitative real time PCR in 70 tissue specimens. The results showed that CFL1 mRNA level was over‐expressed in ESCC tissue (P < 0.05), while N‐WASP mRNA expression level was not different between cancerous tissues and adjacent normal esophageal mucosa (P > 0.05). Also, CFL1 mRNA expression was significantly associated with regional lymph node metastasis and pathological staging (P < 0.05). Kaplan–Meier analysis showed that there was no correlation between CFL1 and N‐WASP mRNA expression and survival (P > 0.05). Our findings suggested that CFL1 and N‐WASP may play an important role in the tumorigenesis of ESCC, and to be the candidate novel biomarkers for the diagnosis and prognosis of ESCC. These findings may have implications for targeted therapies in patients with ESCC.     

Overexpression of HSP47 in esophageal squamous cell carcinoma: clinical implications and functional analysis

Several biomarkers of esophageal squamous cell carcinoma (ESCC) have been explored to improve the prognosis of this disease. One of these, the 47‐kDa heat shock protein (HSP47), has been screened as a potential biomarker by genomic profiling and is known to be overexpressed in some malignant diseases. In this study, we explored the role and evaluated the prognostic value of HSP47 expression in ESCC. The function of this protein was analyzed by assaying proliferation, wound healing, and colony formation in an HSP47‐knockdown ESCC line. The prognostic implication of HSP47 expression was analyzed by immunohistochemical staining in 157 surgical specimens. HSP47 expression level and other clinical variables were analyzed using multivariate Cox proportional hazards models. Silencing of the HSP47 gene in the ESCC cell line inhibited cell proliferation and colony formation. HSP47 was highly expressed in ESCC tissue samples, compared with normal esophageal tissues. The level of immunohistochemical staining of HSP47 and pathologic stage were significantly correlated with overall and recurrence‐free survival, as shown by multivariate analysis (P = 0.014 and 0.044, respectively). We found that overexpression of HSP47 is associated with poor prognosis in patients with ESCC and that this is consistent with the function of HSP47 in terms of increased cell proliferation and colony formation. These results suggest that HSP47 is a potential prognostic biomarker for ESCC and merits further research for novel diagnostic and therapeutic applications.     

ZFX promotes tumorigenesis and confers chemotherapy resistance in esophageal squamous cell carcinoma

IntroductionZinc finger X-chromosomal protein (ZFX) has been shown to be essential for the development and progression of multiple types of human cancers. However, its potential roles in esophageal squamous cell carcinoma (ESCC) have not yet been elucidated.Materials and methodsEighty-three pairs of frozen ESCC samples and their para-cancer samples and 24 fresh ESCC samples were collected. In vitro chemosensitivity was tested using the histoculture drug response assay. Quantitative RT-PCR and western blotting were used to measure the expression of functional genes. The effects of ZFX on cell growth, cell apoptosis, and chemosensitivity of the esophageal cancer cells were assessed.ResultsWe found that ZFX was more upregulated in ESCC tissues than in the para-cancer tissues, and its high expression was correlated with inferior clinicopathological characteristics and overall survival. Multivariate analysis revealed that ZFX was an independent prognostic factor in ESCC patients. In ESCC cell lines, ZFX silencing suppressed cell growth and induced cell apoptosis. In addition, ZFX expression was negatively correlated with the sensitivity of fresh ESCC tissues to chemotherapeutic drugs, including cisplatin, docetaxel, fluorouracil, and irinotecan. Furthermore, the depletion of ZFX sensitized ESCC cells to cisplatin, and docetaxel treatment. Mechanistically, ZFX silencing resulted in the inactivation of the MEK/ERK pathway, which mediated the downregulation of P-glycoprotein expression.ConclusionOur study therefore indicates that ZFX possibly plays a critical role in ESCC tumorigenesis and chemotherapy resistance and could be a significant prognostic biomarker and therapeutic target for ESCC.     

Clinicopathological significance of cyclooxygenase‐2 and cell cycle‐regulatory proteins expression in patients with esophageal squamous cell carcinoma

The aim of this study was to examine the expression of the molecular markers cyclooxygenase‐2 (COX‐2), Ki‐67, cyclin A, and p27 in patients with esophageal squamous cell carcinoma (ESCC), to ascertain the relationship of these makers with the clinicopathological significance of the patients, and to assess the additional prognostic value of the expression profile of these proteins for ESCC patients. The expression levels of COX‐2, Ki‐67, cyclin A, and p27 proteins of a series of primarily resected ESCC samples were determined by immunohistochemistry method. Clinicopathological and molecular factors affecting survival were analyzed by multivariate analysis. A total of 78 specimens were included in this study. Expression of COX‐2 was observed in 43 (55.1%) cases, and high levels of expression of Ki‐67, p27, and cyclin A were observed in 57 (73.0%), 33 (42.3%), 43 (55.1%) cases, respectively. The results of univariate survival analysis indicated that more advanced tumor stage, lymph node involvement, systemic dissemination, the levels of expression of COX‐2, Ki‐67, cyclin A, and p27 were associated with survival (all P‐value < 0.05). Multifactorial survival analysis revealed that only lymph node involvement, over‐expression of cyclin A, and low p27 expression were associated with the survival of the patients (hazard ratios = 2.83, 4.7, 2.9, respectively; P= 0.025, 0.042, 0.005, respectively). Among the molecular markers assessed, the expression of cell proliferation markers cyclin A and p27 are independent prognostic factors in patients with ESCC, whereas neither COX‐2 nor Ki‐67 is of independent prognostic value.     

Preoperative level of serum amyloid A is superior to C‐reactive protein in the prognosis of esophageal squamous cell carcinoma

Preoperative elevations in the levels of serum amyloid A (SAA) or C‐reactive protein (CRP) have been reported to be prognostic indicators in several malignancies. The aim of this study is to evaluate the serum levels of SAA and CRP in the prognosis of esophageal squamous cell carcinoma (ESCC). In total, 252 patients with ESCC who had undergone surgery with curative‐intent were retrospectively recruited. The specificity, sensitivity, and prognostic value of SAA or CRP levels were measured as the area under the receiver operating characteristic (ROC) curve (AUC). The clinical value of SAA and CRP levels as prognostic indicators was evaluated using Cox's proportional hazards model. The 1‐, 3‐, and 5‐year overall survival (OS) rates for the entire cohort of patients with ESCC were 71.0%, 61.0%, and 43.0%, respectively. The correlation between the levels of SAA and CRP was significant (r² = 0. 685, P < 0.001). The ROC analysis showed that the levels of CRP were associated with a significantly lower overall accuracy than were the SAA levels (AUC, 0.615 vs. 0.880; P < 0.001). For the complete cohort, the median OS was 52.0 months longer in patients with low preoperative serum levels of SAA (72.0 months) compared with patients who had high SAA levels (20.0 months, P < 0.001). The median OS among patients with low CRP levels was also longer compared with the patients who had high CRP levels (72.0 vs. 51.0 months, respectively; P < 0.001). Subgroup analyses showed that the preoperative elevated levels of SAA could find significant differences in OS for stage I, stage II, and stage III (P < 0.001, P = 0.001, and P < 0.001, respectively), whereas the increased levels of CRP could only find a difference in OS for stage II cancers. After a multivariate analysis, preoperative elevated level of SAA was found to be an independently and significant prognostic factor (P < 0.001). Our study indicates that the preoperative levels of SAA and CRP can act as prognostic factors, and that elevated levels of these proteins are associated with negative effects on the survival of patients with ESCC. SAA showed a higher prognostic value than CRP in both cohort and subgroup analysis.     

USP22 nuclear expression is significantly associated with progression and unfavorable clinical outcome in human esophageal squamous cell carcinoma

Purpose

To detect the expression levels of ubiquitin-specific protease 22 (USP22) in human esophageal squamous cell carcinoma (ESCC) and to correlate it with clinicopathologic and prognostic data.

Methods

The immunoreactivity of USP22 protein was analyzed in 157 pathologically characterized ESCC tissues by immunohistochemistry. All statistical analyses were performed with SPSS statistical software to evaluate the association of USP22 protein with clinicopathologic factors and survival.

Results

High expression of USP22 protein was detected in 50.96?% of 157 ESCC tissues and significantly associated with invasion depth, lymph node metastasis, pathologic stage and tumor relapse (P?P?=?0.002), and multivariate survival analysis showed that high expression of USP22 protein was an independent prognosticator for unfavorable disease-specific survival (P?=?0.039). Further survival analysis stratified by pathologic stage demonstrated that high expression of USP22 protein significantly predicted unfavorable clinical outcome (P?=?0.029) among patients with pathologic stage II_b–III diseases.

Conclusion

USP22 protein plays an essential role in ESCC progression and has clinical potentials not only as a promising biomarker to identify the subgroup of patients with more aggressive tumors and poor prognostic potential but also as an attractively therapeutic target for ESCC.     

Relationship between altered expression levels of MIR21, MIR143, MIR145, and MIR205 and clinicopathologic features of esophageal squamous cell carcinoma

In spite of the undisputed importance of altered expression patterns of microRNAs (miRNAs) in various cancers, there is little information on the clinicopathologic significance of cancer‐related miRNAs (MIR21, MIR143, MIR144, MIR145, and MIR205) in esophageal squamous cell carcinoma (ESCC). We examined the expression levels of the precursor and mature miRNA genes in ESCC using real‐time polymerase chain reaction (PCR). We also investigated the mRNA expression levels of processing elements (RNASEN, DGCR8, and DICER1) that participate in miRNA‐biogenesis pathway. Furthermore, we analyzed the relationships between the expression levels of these five miRNAs and the clinicopathologic parameters of ESCC patients. The expression levels of mature MIR21 and mature MIR145 were higher in ESCC than those in normal epithelium (P < 0.05). The mature/pre ratio of MIR21 in ESCC was higher than that in normal epithelium (P < 0.05). With regard to miRNA‐processing elements, the expression level of RNASEN was higher in ESCC than in normal epithelium (P < 0.05). Furthermore, altered expression of these miRNAs was related to the clinicopathologic features of ESCC patients. The high expression of mature MIR21 and mature MIR205 was associated with lymph node positivity in ESCC patients (P < 0.05). The high levels of expression of mature MIR143 and mature MIR145 were associated with recurrence of metastasis in ESCC patients (P < 0.05). The findings may imply that miRNA biogenesis is aberrantly accelerated in ESCC. Analysis of the expression levels of miRNAs should provide useful information for evaluation of the staging, prognosis, and treatment of ESCC patients.     

Immunohistochemical analysis on potential new molecular targets for esophageal cancer

Despite multimodal therapeutic options, esophageal cancer is still among the most deadly malignancies. In the past decade, targeted therapy has shown great potential in other cancers, but data on esophageal carcinoma are still rare. Five potential new molecular targets in esophageal adenocarcinoma (EAC) and esophageal squamous cell carcinoma (ESCC) were investigated for their expression characteristics: vascular endothelial growth factor receptor (VEGFR)‐3, human epidermal growth factor receptor‐2, stem cell growth factor receptor, tissue inhibitors of metalloproteinase (TIMP)‐4 and TIMP‐3. One hundred seventy‐one EAC and ESCC tissue samples obtained from patients undergoing esophagectomy from 2000 to 2008 were included. Clinical data were evaluated retrospectively. Immunohistochemical staining was performed using tumor tissue with and without neoadjuvant treatment and healthy tissue. For samples without neoadjuvant treatment, expression of all targets was higher in tumor tissue than in healthy tissue except for VEGFR‐3 (>98% expression in both tissues). For TIMP‐4, TIMP‐3 and stem cell growth factor receptor, trends to higher expression in tumor tissue were also found in EAC and ESCC that had received neoadjuvant treatment. Using Matched‐pair analysis, we compared target expression in tumor tissue with and without neoadjuvant treatment. Only TIMP‐3 had significantly lower expression in neoadjuvant treated tumor tissue (EAC: P = 0.059, ESCC: P = 0.006). TIMP‐4, TIMP‐3 and VEGFR‐3 appear to qualify for targeted therapy in esophageal cancer because of their high expression in neoplastic tissue. TIMP‐3 appears to be downregulated in neoadjuvantly treated esophageal cancer, and VEGFR‐3 shows high expression in healthy mucosa leading to severe side effects by molecular targeting. Thus, TIMP‐4 seems the most promising target.     

Serum soluble E‐cadherin is a potential prognostic marker in esophageal squamous cell carcinoma

E‐cadherin is a well‐documented tumor suppressor with downregulated expression in many cancer types. Upon proteolytic cleavage, a soluble form of 80‐kDa degradation fragment, known as soluble E‐cadherin (s‐Ecad), is present in circulation; its level in sera of cancer patients is significantly associated with metastasis, recurrence, and prognosis in some malignancies. The present study investigated the association of s‐Ecad with clinicopathological characteristics of patients with esophageal squamous cell carcinoma (ESCC) and its prognostic significance. A cohort of 97 patients who underwent surgery alone (n= 56) or neoadjuvant chemoradiation therapy and surgery (CRT) (n= 41) was recruited for this study. Serum samples were collected at operation (surgery group) and pre‐ and post‐CRT treatment (CRT group) for measurement of s‐Ecad protein by enzyme linked immunosorbent assay. Serum s‐Ecad levels were correlated with clinicopathological parameters as well as survival. Univariate analysis showed no significant relationship between serum s‐Ecad level and clinicopathological parameters for all sets of samples. Survival analysis showed that in patients who had surgical resection only, those with s‐Ecad levels equal to or below the median value survived significantly longer than those with levels above the median (median survival 25.6 vs. 14.1 months, P= 0.012). Multivariate analysis showed that pathological N stage, M stage, R category, and serum s‐Ecad level were significant independent prognostic factors for ESCC patients who underwent surgery only. The hazard ratio for s‐Ecad was 1.104 (95% CI: 1.026–1.187) and P= 0.008. Serum s‐Ecad was detected in ESCC patients and its potential as an independent prognostic marker requires further investigation.