Current status of predictive biomarkers for neoadjuvant therapy in esophageal cancer

Risk Stratification by Tissue GAD1 Expression Level in Curatively Resected Esophageal Squamous Cell Carcinoma

BACKGROUND/AIM

To improve patient management, new biomarkers are required that stratify prognosis. Here we focused on glutamic acid decarboxylase 1 (GAD1), which is associated with proliferation of lung cancer cells, and investigated its expression and function in esophageal squamous cell carcinoma (ESCC).

MATERIALS AND METHODS

We evaluated changes in the proliferative potential of ESCC cell lines using small interfering RNA-mediated GAD1 knockdown techniques. We analyzed GAD1 protein expression using a tissue microarray (TMA) and measured GAD1 mRNA expression to evaluate correlations between the expression level of each tissue and postoperative outcomes of two independent cohorts (the TMA and mRNA cohorts) of patients who underwent radical esophagectomy.

RESULTS

GAD1 knockdown reduced cell proliferation. In the TMA cohort, high GAD1 expression significantly correlated with lymph node metastasis and advanced stage. Disease-free survival was significantly shorter in the group with high GAD1 expression, as was overall survival. Multivariate analysis of overall survival showed that positivity for GAD1 was an independent prognostic factor for poor survival. In the mRNA cohort, GAD1 mRNA expression in ESCC tissues was significantly up-regulated compared with that in adjacent noncancerous mucosal tissues. When patients were divided into high- and low-expression groups according to the median GAD1 mRNA expression level in ESCC tissues, overall survival was significantly shortened in the high GAD1 expression group. The incidence of initial hematogenous recurrence was significantly higher in the group with high GAD1 expression.

CONCLUSION

GAD1 expression mediates the proliferative potential of ESCC cells, and a high level may serve as a useful prognostic biomarker for patients with ESCC.

Skeletal Muscle Loss During Neoadjuvant Chemotherapy Predicts the Incidence of Postoperative Infectious Complications in Esophageal Cancer Patients Undergoing Esophagectomy

BACKGROUND/AIM

Malnutrition, immune deficiency, and skeletal muscle loss are associated with a risk of postoperative complications in patients with various types of cancer. This study evaluated whether malnutrition, immunological deficiencies, and skeletal muscle loss during neoadjuvant chemotherapy (NAC) predict postoperative complications in patients with esophageal cancer.

PATIENTS AND METHODS

We retrospectively reviewed 123 patients with esophageal squamous cell carcinoma treated with NAC and esophagectomy at our hospital between 2014 and 2019. Patients were divided into two groups based on the presence or absence of postoperative infectious complications, such as pneumonia, anastomotic leakage, surgical site infections, pyothorax, acalculous cholecystitis, and peripheral phlebitis. Neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio, and Onodera prognostic nutritional index were used as indicators of systemic inflammation and nutritional status. Skeletal muscle mass was evaluated using the skeletal muscle index (SMI), calculated by evaluating the total cross-sectional area of muscle tissue at the third lumbar level in computed tomography imaging. Univariable and multivariable logistic regression analyses were used to identify predictors of postoperative infectious complications.

RESULTS

Postoperative infectious complications occurred in 41 patients (33.3%). A reduction in SMI was observed in 105 patients (87.8%) during NAC. Univariable and multivariable analyses indicated that the reduction in SMI during NAC was an independent predictor of postoperative complications (odds ratio=0.89; 95% confidence interval=0.79-0.99; p=0.048).

CONCLUSION

Skeletal muscle loss during NAC is a useful predictor of postoperative complications in patients with esophageal cancer undergoing esophagectomy.

Prognostic and predictive biomarkers for response to neoadjuvant chemoradiation in esophageal adenocarcinoma

Background

Esophageal adenocarcinoma is a lethal disease. For locally advanced patients, neoadjuvant chemoradiotherapy followed by surgery is the standard of care. Risk stratification relies heavily on clinicopathologic features, particularly pathologic response, which is inadequate, therefore establishing the need for new and reliable biomarkers for risk stratification.

Methods

Thirty four patients with locally advanced esophageal adenocarcinoma were analyzed, of which 21 received a CROSS regimen with carboplatin, paclitaxel, and radiation. Capture-based targeted sequencing was performed on the paired baseline and post-treatment samples. Differentially mutated gene analysis between responders and non-responders of treatment was performed to determine predictors of response. A univariate Cox proportional hazard regression was used to examine associations between gene mutation status and overall survival.

Results

A 3-gene signature, based on mutations in EPHA5, BCL6, and ERBB2, was identified that robustly predicts response to the CROSS regimen. For this model, sensitivity was 84.6% and specificity was 100%. Independently, a 9 gene signature was created using APC, MAP3K6, ETS1, CSF3R, PDGFRB, GATA2, ARID1A, PML, and FGF6, which significantly stratifies patients into risk categories, prognosticating for improved relapse-free (p = 4.73E-03) and overall survival (p = 3.325E-06). The sensitivity for this model was 73.33% and the specificity was 94.74%.

Conclusion

We have identified a 3-gene signature (EPHA5, BCL6, and ERBB2) that is predictive of response to neoadjuvant chemoradiotherapy and a separate prognostic 9-gene classifier that predicts survival outcomes. These panels provide significant potential for personalized management of locally advanced esophageal cancer.

A new biomarker to enhance the radiosensitivity of hepatocellular cancer: miRNAs

Aims: This review summarizes findings regarding miRNAs that modulate radiation in hepatocellular carcinoma (HCC) and evaluates their potential clinical therapeutic uses. Materials & methods: We searched the relevant English-language medical databases for papers on miRNAs and radiation therapy for tumors to identify miRNAs that are linked with radiosensitivity and radioresistance, focusing on those associated with HCC radiation. Results: There were 88 papers assessed for miRNAs associated with tumor radiation, 56 of which dealt with radiosensitization, 21 with radioresistance and 11 with radiosensitization for HCC. Conclusion: Further work in this area would enable future evaluation of radiation responses and the potential use of miRNAs as therapeutic agents in HCC patients.

PLEK2, RRM2, GCSH: A Novel WWOX-Dependent Biomarker Triad of Glioblastoma at the Crossroads of Cytoskeleton Reorganization and Metabolism Alterations

Glioblastoma is one of the deadliest human cancers. Its malignancy depends on cytoskeleton reorganization, which is related to, e.g., epithelial-to-mesenchymal transition and metastasis. The malignant phenotype of glioblastoma is also affected by the WWOX gene, which is lost in nearly a quarter of gliomas. Although the role of WWOX in the cytoskeleton rearrangement has been found in neural progenitor cells, its function as a modulator of cytoskeleton in gliomas was not investigated. Therefore, this study aimed to investigate the role of WWOX and its collaborators in cytoskeleton dynamics of glioblastoma. Methodology on RNA-seq data integrated the use of databases, bioinformatics tools, web-based platforms, and machine learning algorithm, and the obtained results were validated through microarray data. PLEK2, RRM2, and GCSH were the most relevant WWOX-dependent genes that could serve as novel biomarkers. Other genes important in the context of cytoskeleton (BMP4, CCL11, CUX2, DUSP7, FAM92B, GRIN2B, HOXA1, HOXA10, KIF20A, NF2, SPOCK1, TTR, UHRF1, and WT1), metabolism (MTHFD2), or correlation with WWOX (COL3A1, KIF20A, RNF141, and RXRG) were also discovered. For the first time, we propose that changes in WWOX expression dictate a myriad of alterations that affect both glioblastoma cytoskeleton and metabolism, rendering new therapeutic possibilities.

Regulation of MRE11A by UBQLN4 leads to cisplatin resistance in patients with esophageal squamous cell carcinoma

Resistance to standard cisplatin‐based chemotherapies leads to worse survival outcomes for patients with esophageal squamous cell carcinoma (ESCC). Therefore, there is an urgent need to understand the aberrant mechanisms driving resistance in ESCC tumors. We hypothesized that ubiquilin‐4 (UBQLN4), a protein that targets ubiquitinated proteins to the proteasome, regulates the expression of Meiotic Recombination 11 Homolog A (MRE11A), a critical component of the MRN complex and DNA damage repair pathways. Initially, immunohistochemistry analysis was conducted in specimens from patients with ESCC (n = 120). In endoscopic core ESCC biopsies taken from 61 patients who underwent neoadjuvant chemotherapy (NAC) (5‐fluorouracil and cisplatin), low MRE11A and high UBQLN4 protein levels were associated with reduced pathological response to NAC (P < 0.001 and P < 0.001, respectively). Multivariable analysis of surgically resected ESCC tissues from 59 patients revealed low MRE11A and high UBLQN4 expression as independent factors that can predict shorter overall survival [P = 0.01, hazard ratio (HR) = 5.11, 95% confidence interval (CI), 1.45–18.03; P = 0.02, HR = 3.74, 95% CI, 1.19–11.76, respectively]. Suppression of MRE11A expression was associated with cisplatin resistance in ESCC cell lines. Additionally, MRE11A was found to be ubiquitinated after cisplatin treatment. We observed an amplification of UBQLN4 gene copy numbers and an increase in UBQLN4 protein levels in ESCC tissues. Binding of UBQLN4 to ubiquitinated‐MRE11A increased MRE11A degradation, thereby regulating MRE11A protein levels following DNA damage and promoting cisplatin resistance. In summary, MRE11A and UBQLN4 protein levels can serve as predictors for NAC response and as prognostic markers in ESCC patients.

Anlotinib Combined With Chemoradiotherapy Exhibits Significant Therapeutic Efficacy in Esophageal Squamous Cell Carcinoma

Objective: The aim of this study was to evaluate the safety and efficacy of anlotinib combined with chemoradiotherapy for treating esophageal squamous cell carcinoma (ESCC) using patient-derived xenografts (PDXs). Methods: PDX-bearing mice were randomly divided into five groups, as follows: control group receiving normal saline, the group receiving radiotherapy, the group receiving cisplatin combined with radiotherapy, the group receiving anlotinib combined with radiotherapy, and the group receiving anlotinib, and cisplatin combined with radiotherapy. Tumor volumes and body weights were measured three times weekly for 2 weeks. The PDXs were initially assessed by comparing the histology of the original patient tumor tissues with that of the corresponding serially passaged xenografts by hematoxylin and eosin (H&E) and P63 staining. Then, expression of Bax, c-PARP, PCNA, and CD31 was detected using immunohistochemistry, and apoptosis was detected by a TUNEL assay. Cytokines released into plasma were analyzed using protein chip technology. Finally, two case studies of ESCC patients were presented to further verify the results observed in the PDX models. Results: The pathological characteristics of the serially passaged patient tumor-derived xenografts established in our study were in line with those of the original ESCC patient samples. The group receiving anlotinib and cisplatin plus radiotherapy exhibited the strongest antitumor response among the groups. Moreover, the ideal anticancer effects of anlotinib combined with chemoradiotherapy observed in clinical patients were consistent with the results observed in the PDX models, and no serious side effects were observed during treatment. Conclusions: Combination therapy with anlotinib and chemoradiotherapy may be an effective regimen for the treatment of advanced ESCC.

KCNJ15 Expression and Malignant Behavior of Esophageal Squamous Cell Carcinoma

BACKGROUND

We aimed to clarify the role of potassium voltage-gated channel subfamily J member 15 (KCNJ15) in esophageal squamous cell carcinoma (ESCC) cells and its potential as a prognosticator in ESCC patients.

METHODS

KCNJ15 transcription levels were evaluated in 13 ESCC cell lines and polymerase chain reaction (PCR) array analysis was conducted to detect coordinately expressed genes with KCNJ15. The biological functions of KCNJ15 in cell invasion, proliferation, migration, and adhesion were validated through small interfering RNA-mediated knockdown experiments. Cell proliferation was further evaluated through the forced expression experiment. KCNJ15 expression was detected in 200 ESCC tissues by quantitative real-time reverse transcription PCR (qRT-PCR) and analyzed in 64 representative tissues by immunohistochemistry. Correlations between KCNJ15 expression levels and clinicopathological features were also analyzed.

RESULTS

The KCNJ15 expression levels varied widely in ESCC cell lines and correlated with COL3A1, JAG1, and F11R. Knockdown of KCNJ15 expression significantly repressed cell invasion, proliferation, and migration of ESCC cells in vitro. Furthermore, overexpression of KCNJ15 resulted in increased cell proliferation. Patients were stratified using the cut-off value of KCNJ15 messenger RNA (mRNA) levels in 200 ESCC tissues using receiver operating characteristic curve analysis; the high KCNJ15 expression group had significantly shorter overall and disease-free survival times. In multivariable analysis, high expression of KCNJ15 was identified as an independent poor prognostic factor. Staining intensity of in situ KCNJ15 protein expression tended to be associated with KCNJ15 mRNA expression levels.

CONCLUSIONS

KCNJ15 is involved in aggressive tumor phenotypes of ESCC cells and its tissue expression levels may be useful as a prognosticator of patients with ESCC.

Downregulation of AAA-domain-containing protein 2 restrains cancer stem cell properties in esophageal squamous cell carcinoma via blockade of the Hedgehog signaling pathway

Esophageal squamous cell carcinoma (ESCC) ranks among the five most common cancers in China and has a five-year survival rate of less than 15%. The transcription factor ATPase-family AAA-domain-containing protein 2 (ATAD2) has potential as a therapeutic target in various tumors, and microarray-based gene expression profiling reveals dysregulation of ATAD2 specifically in ESCC. Here we investigated whether ATAD2 could mediate a regulation of cancer stem cell (CSC) biological functions in ESCC. Immunohistochemical staining, reverse transcription quantitative polymerase chain reaction, and Western blot assays all revealed upregulation of ATAD2 in ESCC tissues and cell lines, which furthermore correlated with progression of ESCC. In loss-of-function experiments, silencing of ATAD2 inhibited activation of the Hedgehog signaling pathway, as indicated by reduced expression of glioma-associated oncogene family zinc finger 1 (Gli1), smoothened frizzled class receptor (SMO), and patched 1 (PTCH1). Investigations with 5-ethynyl-2'-deoxyuridine (EdU), Transwell assay, scratch test, flow cytometry, and colony formation assay showed that silencing of ATAD2 or inhibiting the Hedgehog signaling decreased the proliferation, invasion, and migration abilities along with colony formation, but elevated the apoptosis rate of CSCs. Furthermore, in vivo experiments validated the suppressive effect of siRNA-mediated ATAD2 silencing on tumor growth in nude mice. Thus, downregulation of ATAD2 can seemingly restrain the malignant phenotypes of ESCC cells through inhibition of the Hedgehog signaling pathway.

Clinical relevance of histologic subtypes in locally advanced esophageal carcinoma treated with pre-operative chemoradiotherapy: Experience of a monographic oncologic centre

Background

Locally advanced esophageal carcinoma (LAEC) represents less than 30% of all diagnosed esophageal carcinoma worldwide. The standard of care for resectable tumours consists of preoperative chemoradiotherapy (CRT) followed by surgery. Despite the curative intent, the prognosis is still poor mainly due to relapse. A multidisciplinary approach is required in order to optimize the therapeutic strategy and follow-up. Differences in outcomes between the two main histological subtypes, adenocarcinoma (ADC) and squamous cell carcinoma (SCC), have been reported. Nevertheless, the heterogeneity in trials design and data available have hampered the achievement of clear conclusions. The purpose of this study is to report the outcomes from a cohort of patients with LAEC treated with a multidisciplinary approach and to remark the differences observed between the two main histologic subtypes and their clinical implications.

Methods

We retrospectively reviewed 100 patients diagnosed with LAEC that were treated with preoperative CRT at our institution and integrated centres. Histopathological characteristics and toxicities during treatment were recorded. Patterns of recurrence at the first relapse were analysed. Survival curves were plotted using the Kaplan Meier method and multivariate Cox proportional hazards models were used.

Results

Among the patients who received preoperative CRT, 83% underwent surgery. The median overall survival (mOS) was 31.7 months, 26.9 months for ADC and 45.5 for SCC (p-value = 0.33). In the multivariate Cox regression analysis, ypN+ was the only factor that negatively influenced in OS (OR = 4.1, p-value = 0.022). Patterns of recurrence differed according to histologic subtype. Distant relapse was more frequent in ADC (62%), whereas locoregional relapse was higher in SCC (50%) (p-value = 0.027). Second line therapeutic strategies could be offered to 50% of those patients who relapsed.

Conclusions

Differences in outcomes and recurrence pattern could be observed between the two main histologic subtypes of LAEC. A better molecular characterization, adapted therapeutic regimens and follow up strategies should be adopted in order to improve survival of these patients.

The mechanisms of radioresistance in esophageal squamous cell carcinoma and current strategies in radiosensitivity

Esophageal cancer is the eighth most common cancer and the sixth leading cause of cancer-related death worldwide. Surgery is the primary form of treatment, but the survival is poor, especially for patients with locally advanced esophageal cancer. Radiotherapy has been a critical treatment option that may be combined with chemotherapy in patients with unresectable esophageal cancer. However, resistance to chemoradiotherapy might result in treatment failures and cancer relapse. This review will mainly focus on the possible cellular mechanisms and tumor-associated microenvironmental (TAM) factors that result in radioresistance in patients with esophageal cancer. In addition, current strategies to increase radiosensitivity, including targeted therapy and the use of radiosensitive biomarkers in clinical treatment, are discussed in this review.

Effect of neoadjuvant chemoradiotherapy on perioperative immune function of patients with locally advanced esophageal cancer

This study aims to evaluate the effect of neoadjuvant chemoradiotherapy (NCRT) on perioperative immune function during surgery to treat resectable locally advanced esophageal cancer. Records were retrospectively analyzed for 220 patients with locally advanced esophageal cancer, of whom 112 received surgery alone and 98 received neoadjuvant NCRT plus surgery. The two groups were compared in terms of proportions of CD3+, CD4+, CD8+, and natural kill (NK) cells, as well as the ratio of CD4+ to CD8+ cells. These measurements were made using flow cytometry on preoperative day 1 and on postoperative days 1 and 7. Subgroup analysis were performed in terms of degrees of pathological response of NCRT. When the entire NCRT and no-NCRT (surgery alone) cohorts were compared, no significant differences in propocrtions of CD3+, CD4+, CD8+, or NK cells or in the CD4+/CD8+ ratio occurred at any of the three time points. Similar results were obtained using the subgroup of NCRT patients who were NCRT-sensitive, but the subgroup of NCRT-insensitive patients showed significantly lower CD4+ and NK proportions and lower CD4+/CD8+ ratio than the no-NCRT group. Our findings suggest that NCRT does not affect perioperative immune function in patients who are NCRT-sensitive, but it does significantly reduce such function in patients who are NCRT-insensitive.

Impact of Neoadjuvant Chemoradiation on Short-Term Outcomes for Esophageal Squamous Cell Carcinoma Patients: A Meta-analysis

BACKGROUND

Neoadjuvant chemoradiation (NCRT) has emerged as a component of the standard treatment for esophageal squamous cell carcinoma (SCC). The primary benefit of NCRT is an improvement in long-term survival; however, the impact of NCRT on short-term outcomes is unclear.

METHODS

A comprehensive electronic literature search was performed via the MEDLINE (PubMed), Cochrane Library, and Google Scholar databases through November 2015 for the inclusion of randomized controlled trials (RCTs) that evaluated short-term outcomes of patients administered NCRT followed by surgery compared with surgery alone for resectable esophageal SCC. The main outcome measures were postoperative mortality and morbidity. A meta-analysis was performed using random-effects models to calculate odds ratios (ORs) with 95 % confidence intervals (CIs).

RESULTS

Eight RCTs were included, for a total of 1058 patients. Meta-analysis of the overall postoperative mortality and cardiopulmonary complication rates showed that there was a significant increase for patients administered NCRT followed by surgery compared with surgery alone (OR 1.87, 95 % CI 1.07-3.28, p = 0.03, number of patients needed to harm = 33.3; and OR 2.12, 95 % CI 1.03-4.35, p = 0.04, respectively). Dropout before surgery was higher for patients in the NCRT followed by surgery group compared with patients in the surgery-alone group. NCRT has no statistically impact on anastomosis and other complications compared with surgery alone.

CONCLUSIONS

NCRT for esophageal SCC significantly increases postoperative mortality and cardiopulmonary complications.

MicroRNAs and Their Impact on Radiotherapy for Cancer

Resistance to radiation is considered to be an important reason for local failure after radiotherapy and tumor recurrence. However, the exact mechanisms of tumor resistance remain poorly understood. Current investigations of microRNAs as potential diagnostic and therapeutic tools for cancer treatment have shown promising results. With respect to radiotherapy resistance and response, there is now emerging evidence that microRNAs modulate key cellular pathways that mediate response to radiation. These data suggest that microRNAs might have significant potential as targets for the development of new therapeutic strategies to overcome radioresistance in cancer. This review summarizes the current literature pertinent to the influence of microRNAs in the response to radiotherapy for cancer treatment, with an emphasis on microRNAs as novel diagnostic and prognostic markers, as well as their potential to alter radiosensitivity.

Potential biomarkers for esophageal cancer

Esophageal cancer, which consist of esophageal adenocarcinoma and esophageal squamous cell carcinoma, is one of the most common malignant tumors in the world, especially in the south of Iran and China. To find and investigate the biomarkers in the initiation, development and progression of esophageal cancer will help us predict the prognosis of esophageal cancer patients and improve the curative effect and survival rate. Here, we reviewed the potential biomarkers of esophageal cancer in three aspects: Immunohistochemical markers, blood-based markers, miRNA markers and Gene expression profiling. All these biomarkers provided promising therapeutic targets for the diagnosis, treatment, and prognosis of esophageal cancer.

A method for establishing a patient-derived xenograft model to explore new therapeutic strategies for esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (ESCC) is the predominant histological type of esophageal carcinoma in China. The overall 5-year survival rate of ESCC patients is in the low range of 15-25%. One important reason for the poor prognosis is that the underlying molecular mechanisms are unclear. Furthermore, the development of effective therapeutic strategies to improve patient outcome is needed. Animal models can be beneficial to analyze the molecular mechanisms as well as specific clinical therapeutic strategies for esophageal cancer. In recent years, patient-derived xenografts (PDXs) have been widely used in numerous types of cancers to investigate the basic mechanisms and to conduct preclinical research. Accumulating evidence indicates that the PDX model is an important tool for basic and clinical research. Herein, we successfully established 14 ESCC PDXs. These PDX models preserved the patient pathological characteristics and effectively reflected the patient biological heterogeneity. Cancers exhibit diverse growth rates and tumor texture, even more, they have different signaling pathways. The PDX model is a superior strategy for understanding the underlying molecular mechanisms of ESCC and for screening new therapeutic strategies for ESCC patients.

Germline and somatic genetic predictors of pathological response in neoadjuvant settings of rectal and esophageal cancers: systematic review and meta-analysis

Oncologists have pointed out an urgent need for biomarkers that can be useful for clinical application to predict the susceptibility of patients to preoperative therapy. This review collects, evaluates and combines data on the influence of reported somatic and germline genetic variations on histological tumor regression in neoadjuvant settings of rectal and esophageal cancers. Five hundred and twenty-seven articles were identified, 204 retrieved and 61 studies included. Among 24 and 14 genetic markers reported for rectal and esophageal cancers, respectively, significant associations in meta-analyses were demonstrated for the following markers. In rectal cancer, major response was more frequent in carriers of the TYMS genotype 2 R/2 R-2 R/3 R (rs34743033), MTHFR genotype 677C/C (rs1801133), wild-type TP53 and KRAS genes. In esophageal cancer, successful therapy appeared to correlate with wild-type TP53. These results may be useful for future research directions to translate reported data into practical clinical use.

Combined downregulation of microRNA-133a and microRNA-133b predicts chemosensitivity of patients with esophageal squamous cell carcinoma undergoing paclitaxel-based chemotherapy

microRNA-133a (miR-133a) and miR-133b, located on chromosome 18 in the same bicistronic unit, have been commonly identified as being downregulated in esophageal squamous cell carcinoma (ESCC). The aim of this study was to investigate the correlation of miR-133a/b expression with efficacy of paclitaxel-based chemotherapy and clinical outcome of ESCC patients. miR-133a expression and miR-133b expression were examined in 100 newly diagnosed ESCC patients prior to treatment by quantitative real-time PCR. Then, the patients received four cycles of paclitaxel-based chemotherapy, the short-term treatment efficacy was evaluated, and a 3-year follow-up was performed. Expression levels of miR-133a and miR-133b were both significantly lower in ESCC tissues compared to adjacent noncancerous tissues (both P < 0.001). In addition, combined miR-133a/b downregulation was found to be closely correlated with advanced tumor stage (P = 0.02) and poor differentiation (P = 0.01). Moreover, the response rate of ESCC patients to paclitaxel-based chemotherapy was significantly higher in combined miR-133a/b downregulation group compared with other groups (P = 0.02). Furthermore, univariate and multivariate Cox analyses revealed that tumor stage and combined expression of miR-133a/b were independent prognosis factors in ESCC patients. Our data offer the convincing evidence that combined expression of miR-133a and miR-133b may predict chemosensitivity of patients with ESCC undergoing paclitaxel-based chemotherapy, implying its importance in applying 'personalized cancer medicine' in the clinical treatment of ESCC. We also identified combined expression of miR-133a and miR-133b as an effective prognostic marker of this malignancy.