Yin Yang 1 suppresses tumor invasion and metastasis in nasopharyngeal carcinoma by negatively regulating eIF4E transcriptional activity and expression.

Tumor metastasis is a leading cause of death in nasopharyngeal carcinoma (NPC) patients. Previous research has identified that transcription factor Yin Yang 1 (YY1) acts as a tumor suppressor that inhibits cell proliferation and tumor growth in NPC; however, the role and the molecular mechanisms of YY1 in NPC invasion and metastasis remain unclear. In this study, we discovered that YY1 could inhibit the migration and invasion of NPC cells in vitro as well as NPC xenograft tumor metastasis in vivo. Furthermore, we identified eIF4E as a direct downstream target of YY1, and YY1 could negatively regulate the expression of eIF4E at transcriptional level. Moreover, we found that eIF4E promoted the migration and invasion of NPC cells as well as NPC lung metastasis, suggesting its potential as a pro-metastatic mediator in NPC. Importantly, restoring eIF4E expression could partially reverse the inhibitory effects of YY1 on NPC malignancy. In consistent with these findings, the expression of YY1 was downregulated while eIF4E was upregulated in NPC patients with metastasis, and there was a negative correlation between YY1 and eIF4E expression. Collectively, our results indicate that YY1 suppresses the invasion and metastasis of NPC by negatively regulating eIF4E transcription. Therefore, targeting the YY1/eIF4E transcriptional axis could be a potential therapeutic strategy for the treatment of patients with NPC.

NOP2/Sun RNA methyltransferase 2 is a potential pan-cancer prognostic biomarker and is related to immunity.

BACKGROUND: NOP2/Sun RNA methyltransferase 2 (NSUN2), an important methyltransferase of m5C, has been poorly studied in cancers, and the relationship between NSUN2 and immunity remains largely unclear. Therefore, the purpose of this study was to explore the expression and prognostic value of NSUN2 and the role of NSUN2 in immunity in cancers. METHODS: The TIMER, CPTAC and other databases were used to analyze the expression of NSUN2, its correlation with clinical stage and its prognostic value across cancers. Moreover, the TISIDB, TIMER2.0 and Sangerbox platform were used to depict the relationships between NSUN2 and immune molecular subtypes, tumor-infiltrating lymphocytes (TILs), immune checkpoints (ICPs) and immunoregulatory genes. Furthermore, the NSUN2-interacting proteins and related genes as well as the coexpression networks of NSUN2 in LIHC, LUAD and HNSC were explored with the STRING, DAVID, GEPIA2 and LinkedOmics databases. Finally, the subcellular location and function of NSUN2 in HepG2, A549 and 5-8F cells were investigated by performing immunofluorescence, CCK-8 and wound healing assays. RESULTS: Overall, NSUN2 was highly expressed and related to a poor prognosis in most types of cancers and was also significantly associated with immune molecular subtypes in some cancer types. Furthermore, NSUN2 was significantly associated with the levels of ICPs and immunoregulatory genes. In addition, NSUN2 was found to be involved in a series of immune-related biological processes, such as the humoral immune response in LIHC and LUAD and T-cell activation and B-cell activation in HNSC. Immunofluorescence and CCK-8 assays also confirmed that NSUN2 was widely expressed in the nucleus and cytoplasm, and overexpression of NSUN2 promoted the proliferation and migration of HepG2, A549 and 5-8F cells. NSUN2 was also confirmed to positively regulate the expression of PD-L1. CONCLUSION: NSUN2 serves as a pan-cancer prognostic biomarker and is correlated with the immune infiltration of tumors.

LncRNA SNHG7 promotes non-small cell lung cancer progression and cisplatin resistance by inducing autophagic activity.

Background: Cisplatin (DDP) is among the most widely used chemotherapeutic drugs for non-small cell lung cancer (NSCLC), yet the frequent emergence of chemoresistance serves as a major barrier to the treatment of this tumor type. Long non-coding RNAs (lncRNAs) have recently been shown to influence the ability of cells to resist particular chemotherapy drugs. The present study was developed to explore the role of the lncRNA SNHG7 as a regulator of NSCLC cell chemosensitivity. Methods: Quantitative real-time polymerase chain reaction (qRT-PCR) was employed to measure SNHG7 expression in NSCLC tissues from patients that were sensitive/resistant to DDP, correlations between SNHG7 expression levels and the patients' clinicopathological characteristics were assessed, and the prognostic relevance of SNHG7 expression was examined via the Kaplan-Meier approach. In addition, SNHG7 expression was assessed in NSCLC cell lines that were DDP-sensitive or -resistant, while western blotting and immunofluorescence staining were employed to detect autophagy-associated protein expression in A549, A549/DDP, HCC827, and HCC827/DDP cells. NSCLC cell chemoresistance was quantified via the Cell Counting Kit-8 (CCK-8) assay approach, and flow cytometry was used to detect the apoptotic death of these tumor cells. The chemosensitivity of xenograft tumors in vivo was further assessed to validate the functional importance of SNHG7 as a regulator of NSCLC DDP resistance. Results: Relative to paracancerous tissues, NSCLC tumors exhibited SNHG7 upregulation, and this lncRNA was further upregulated in DDP-resistant patients compared to chemosensitive patients. Consistently, higher SNHG7 expression levels were correlated with worse patient survival outcomes. DDP-resistant NSCLC cells were also found to exhibit higher levels of SNHG7 expression than chemosensitive cells, and knocking down this lncRNA enhanced the sensitivity of these cells to DDP treatment, resulting in impaired proliferation and higher rates of apoptotic death. Knocking down SNHG7 was also sufficient to suppress microtubule associated protein 1 light chain 3 beta (LC3B) and Beclin1 protein levels and promote p62 upregulation in vitro. The silencing of this lncRNA additionally inhibited the resistance of NSCLC xenograft tumors to DDP treatment in vivo. Conclusions: SNHG7 can promote malignant behaviors and DDP resistance in NSCLC cells at least partly via the induction of autophagic activity.

CircRNA 0009043 suppresses non-small-cell lung cancer development via targeting the miR-148a-3p/DNAJB4 axis.

BACKGROUND: Circular RNAs (circRNAs) are important regulators of the development and progression of non-small-cell lung cancer (NSCLC) and many other malignancies. The functional importance of circ_0009043 in NSCLC, however, has yet to be established. METHODS: The expression of circ_0009043, miR-148a-3p, and DnaJ heat shock protein family (Hsp40) member B4 (DNAJB4) in NSCLC cells was assessed via qPCR. The proliferative activity of these cells was examined through EdU uptake and CCK-8 assays, while flow cytometry approaches were used to examine apoptotic cell death rates. Protein expression was measured through Western immunoblotting. Interactions between miR-148a-3p and circ_0009043 or DNAJB4 were detected through RNA immunoprecipitation (RIP) and dual-luciferase reporter assays. The in vivo importance of circ_0009043 as a regulator of oncogenic activity was assessed using murine xenograft models. RESULTS: Both NSCLC cells and tissue samples were found to exhibit circ_0009043 upregulation, and lower circ_0009043 expression levels were found to be related to poorer NSCLC patient overall survival. Knocking down circ_0009043 resulted in the enhancement of NSCLC cell proliferative activity and the suppression of apoptotic tumor cell death in vitro, while also driving more rapid in vivo tumorigenesis. Mechanistically, circ_0009043 was found to function as a molecular sponge that sequestered miR-148a-3p, which was in turn able to directly suppress DNAJB4 expression. When miR-148a-3p was overexpressed, this reversed the impact of knocking down circ_0009043 on the apoptotic death and proliferation of NSCLC cells. Conversely, miR-148a-3p inhibition resulted in the suppression of NSCLC cell apoptosis and the enhancement of tumor cell growth, while the downregulation of DNAJB4 reversed these changes. CONCLUSION: Circ_0009043 acts as a tumor suppressor in NSCLC cells, promoting DNAJB4 upregulation via the sequestration of miR-148a-3p.

FAIM2 Promotes Non-Small Cell Lung Cancer Cell Growth and Bone Metastasis by Activating the Wnt/ß-Catenin Pathway.

AIM: Bone metastasis is the major reason for the poor prognosis and high mortality rate of non-small cell lung cancer (NSCLC) patients. This study explored the function and underlying mechanism of Fas apoptotic inhibitory molecule 2 (FAIM2) in the bone metastasis of NSCLC. METHODS: Samples of normal lung tissue and NSCLC tissue (with or without bone metastasis) were collected and analyzed for FAIM2 expression. HARA cells with FAIM2 overexpression and HARA-B4 cells with FAIM2 knockdown were tested for proliferation, migration, invasion, anoikis, and their ability to adhere to osteoblasts. Next, whether FAIM2 facilitates bone metastasis by regulating the epithelial mesenchymal transformation (EMT) process and Wnt/ß-catenin signaling pathway were investigated. Finally, an in vivo model of NSCLC bone metastasis was established and used to further examine the influence of FAIM2 on bone metastasis. RESULTS: FAIM2 was highly expressed in NSCLC tissues and NSCLC tissues with bone metastasis. FAIM2 expression was positively associated with the tumor stage, lymph node metastasis, bone metastasis, and poor prognosis of NSCLC. FAIM2 upregulation promoted HARA cell proliferation, migration, and invasion, but inhibited cell apoptosis. FAIM2 knockdown in HARA-B4 cells produced the opposite effects. HARA-B4 cells showed a stronger adhesive ability to osteocytes than did HARA cells. FAIM2 was found to be related to the adhesive ability of HARA and HARA-B4 cells to osteocytes. FAIM2 facilitated bone metastasis by regulating the EMT process and Wnt/ß-catenin signaling pathway. Finally, FAIM2 was found to participate in regulating NSCLC bone metastasis in vivo. CONCLUSIONS: FAIM2 promoted NSCLC cell growth and bone metastasis by regulating the EMT process and Wnt/ß-catenin signaling pathway. FAIM2 might be useful for diagnosing and treating NSCLC bone metastases.

Pemetrexed-based chemotherapy for non-small-cell lung cancer patients with EGFR exon 20 insertion mutation: a multicenter study.

BACKGROUND: Chemotherapy is the major choice for advanced non-small-cell lung cancer (NSCLC) patients with epidermal growth factor receptor exon 20 insertion (EGFR ex20ins). The efficacy of pemetrexed-based with other chemotherapy regimens and EGFR ex20ins subtypes in this population has not been well studied. METHODS: We screened patients with EGFR ex20ins by next-generation sequencing (NGS) from a large cohort. The clinicopathologic and medical information were collected in advanced NSCLC patients with EGFR ex20ins. We also compared the clinical outcomes among patients with different subtypes of EGFR ex20ins. RESULTS: We retrospectively collected 119 stage IIIB/IV NSCLC patients with EGFR ex20ins from 9142 NSCLC patients across China from June 2013 to December 2018. The subtypes of EGFR ex20ins included A767_V769dupASV (33/119, 27.73%), S768_D770dupSVD (19/119, 15.97%), N771_H773dupNPH (11/119, 9.24%), A763_Y764insFQEA (2/119, 1.68%) and others (54/119, 45.38%). A total of 64.7% (77/119) of patients received pemetrexed-based first-line chemotherapy and 13.45% (16/119) of patients received pemetrexed-based second-line chemotherapy. Pemetrexed-based chemo-treated patients had longer median progression-free survival (PFS) than patients without pemetrexed-based chemo-treated (5.5 vs. 3.0 months, P=0.0026). Survival data was available for 66 patients and the median overall survival (OS) was 24.7 months. Pemetrexed-based chemo-treated patients had longer OS tendency than patients without pemetrexed-based chemo-treated (25.0 vs. 19.6 months, P=0.0769). Patients harboring A767_V769dupASV had better OS than other subtypes of EGFR ex20ins but without statistical significance (P=0.0676). Multivariate analysis revealed that histological type of NSCLC and bone-metastasis before treatment were independent prognostic factors for OS in all patients after adjusting all characteristic and treatment factors (P<0.05). CONCLUSIONS: To the best of our knowledge, it is the largest cohort study of advanced NSCLC patients with EGFR ex20ins across China. Pemetrexed-based treatment could have better control of disease than non-pemetrexed-based chemotherapies in this population. Furthermore, more effective agents are expected for patients harboring EGFR ex20ins.

SCD1 is required for EGFR-targeting cancer therapy of lung cancer via re-activation of EGFR/PI3K/AKT signals.

BACKGROUND: Cancer cells are characterized by aberrant activation of lipid biosynthesis, producing saturated fatty acids and monounsaturated fatty acids via stearoyl-CoA desaturases (SCD) for regulating metabolic and signaling platforms. SCD1 overexpression functions as an oncogene in lung cancer and predicts a poor clinical outcome. This study aimed to investigate the role of SCD1 inhibition by EGFR inhibitor (Gefitinib)-based anti-tumor therapy of lung cancer both in vitro and in vivo. METHODS: CCK-8 assay was performed to determine cell viability. The SCD1 mRNA level was detected by qPCR. The protein levels were assessed by Western blotting. E-cadherin and N-cadherin levels were determined by immunofluorescence. Apoptosis detection was conducted by flow cytometry. Cell migration or invasion was evaluated by transwell assay. The tumor sizes and tumor volumes were calculated in nude mice by subcutaneous injection of A549 cells transfected with vector of pcDNA3.1-SCD1 or negative control. Expression of Ki-67 was detected by immunohistochemistry. RESULT: SCD1 up-regulated expression was observed in lung cancer cell lines. Cells with overexpressed SCD1 had high IC50 values for Gefitinib in A549 and H1573 cell lines. Overexpression of SCD1 inhibited Gefitinib-induced apoptosis, decreased cell vitality and impaired ability of migration and invasion, while these effects were counteracted by A939572. Mechanistically, SCD1 promoted the activation of proliferation and metastasis-related EGFR/PI3K/AKT signaling, and up-regulated epithelial to mesenchymal transition (EMT) phenotype in the two cell lines, which was restored by SCD1 inhibition. Furthermore, in spite of EGFR inhibition, overexpression of SCD1 in vivo significantly promoted tumor growth by activating EGFR/PI3K/AKT signaling in tumor tissues, but A939572 treatment restricted SCD1-induced tumor progression and inhibited EMT phenotype of cancer cells in vivo. CONCLUSION: These findings indicated that inhibition of oncogene SCD1 is required for targeting EGFR therapy in lung cancer.

Long non-coding RNA LOC285194 functions as a tumor suppressor by targeting p53 in non-small cell lung cancer.

Recently, LOC285194 has shown a potential tumor-suppressor function in several types of human cancers, but its function in non-small cell lung cancer (NSCLC) remains unknown. This study intended to investigate the biological role of LOC285194 and its clinical significance in NSCLC. LOC285194 was detected by qRT-PCR, and its correlation with clinicopathological features of NSCLC was analyzed. The expression of LOC285194 was knocked down or ectopically expressed in lung cancer cells (A549 and H1299) and tumor cell growth, migration and invasion in vitro were investigated. In addition, the interaction of LOC285194 and target proteins was assessed by RNA pulldown and RNA immunoprecipitation in vitro. The results revealed that the expression of LOC285194 was significantly lower in tumor tissues when compared with the corresponding non-tumor tissues (P<0.001). Its expression was correlated with the tumor size (P=0.027). Kaplan-Meier analysis revealed that patients with lower LOC285194 expression had worse disease-free survival and overall survival rates (P<0.05). RNA protein interaction analysis revealed that p53 was the direct binding target of LOC285194 in NSCLC. Bioinformatics analyses suggested that depletion of LOC285149 could affect its antitumor function through the KRAS/BRAF/SMEK pathway. Our findings indicated that LOC285194 was a novel non-coding prognostic indicator and contributed to tumor suppression by targeting p53 in NSCLC, suggesting that it may be a non-coding target for NSCLC gene therapy.

miR-193b availability is antagonized by LncRNA-SNHG7 for FAIM2-induced tumour progression in non-small cell lung cancer.

OBJECTIVES: Long non-coding RNAs have identified to involve into the tumour cell proliferation, apoptosis and metastasis. We previously found that up-regulated LncRNA-SNHG7 (SNHG7) positively correlated to the Fas apoptosis inhibitory molecule 2 (FAIM2) in lung cancer cells with unclear mechanism. METHODS: Non-small cell lung cancer (NSCLC) and relative normal tissues (n = 25) were collected. The SNHG7 expression and function in NSCLC was determined. The SNHG7-miR 193b-FAIM2 network was analysed in vitro and vivo. RESULTS: We reported that oncogene SNHG7 predicted a poor clinical outcome and functioned as competitive endogenous RNA (ceRNA) antagonized microRNA-193b (miR-193b) to up-regulate the FAIM2 level in NSCLC. Bioinformatic analysis predicted that SNHG7 harboured miR-193b-binding sites, and we found decreased miR-193b levels in NSCLC tissues when compared to relative normal tissues. Luciferase assays indicated that overexpression of miR-193b inhibited the Ruc expression of plasmid with miR-193b-binding sites of SNHG7 in a dose-dependent manner. Ectopically expressed SNHG7 also as a molecular sponge sequestered endogenous miR-193b. Besides, FAIM2 was found to be directly targeted by miR-193b. The restoration of miR-193b levels in NSCLC cell lines A549 and H125 suppressed the expression of FAIM2 and related tumour proliferation, metastasis and induced apoptosis. However, forced expression of SNHG7 could down-regulate miR-193b to elevate the FAIM2 level of tumour cells, leading to impaired miR-193b/FAIM2-induced tumour progression. Knockdown of SNHG7 in vivo significantly delayed the tumour growth with decreased tumour volume, which accompanied with enhanced miR-193b expression and reduced FAIM2 levels. CONCLUSION: The results indicated that miR-193b is indispensible for the ceRNA role of SNHG7 in FAIM2-supported tumourigenesis of lung cancer.

lncRNA-SNHG7 promotes the proliferation, migration and invasion and inhibits apoptosis of lung cancer cells by enhancing the FAIM2 expression.

There is growing evidence that long non-coding RNAs (lncRNAs) are related to cancer development. In the present study, we found that the expression levels of lncRNA-SNHG7 mRNA and protein obviously increased in lung cancer tissues compared to adjacent non-cancerous tissues. Simultaneously, the expression levels of Fas apoptotic inhibitory molecule 2 (FAIM2) also increased in lung cancer tissues. In addition, lncRNA-SNHG7 was of positive relevance with FAIM2 in human lung cancer tissues. Silence of lncRNA­SNHG7 by siRNA repressed the level of FAIM2 protein and suppressed cell proliferation, migration and invasion and accelerated apoptosis of A594 cells in vitro. Furthermore, silence of FAIM2 by siRNA generated a phenotype similar to silence of lncRNA-SNHG7 by siRNA. Therefore, our research showed that lncRNA-SNHG7 promotes the proliferation, migration and invasion, and inhibits apoptosis of lung cancer cells by enhancing the FAIM2 expression, suggesting that lncRNA-SNHG7 as a key regulator of gene expression, may be a promising therapeutic strategy for the treatment of lung cancer. It may improve the understanding of their biogenesis and function of lung cancer and further provide the theoretical fundamental basis for cancer pathogenesis and treatment.

MicroRNA-186 suppresses cell proliferation and metastasis through targeting MAP3K2 in non-small cell lung cancer.

MicroRNAs are a class of small endogenous non-coding RNAs that play crucial roles in the initiation and progression of human cancers. miR-186 was found decreased in various human malignancies and function as a tumor suppressor. However, the regulating mechanism of miR-186 in growth and metastasis of human non-small cell lung cancer (NSCLC) is still poorly understood. We investigated the role of miR-186 in the growth and metastasis of human NSCLC. In the present study, we found that miR-186 was significantly decreased in lung cancer tissues and cells. Furthermore, overexpression of miR-186 suppressed lung cancer cell proliferation, migration and invasion, and induced cell apoptosis. Moreover, we found that confirmed mitogen-activated protein kinase kinase kinase 2 (MAP3K2) protein was increased in lung cancer tissues and confirmed that MAP3K2 is a target gene of miR-186. In addition, knockdown of MAP3K2 by RNA interference inhibited lung cancer cell proliferation, migration and invasion, and promoted cell apoptosis in vitro. Furthermore, we observed tthat the overexpression of MAP3K2 partially reversed the inhibitory effect of miR-186 on the proliferation and metastasis of A549 and HCC827 cell lines. Taken together, our data indicated that miR-186 regulates lung cancer growth and metastasis through suppressing MAP3K2 expression, at least partly. Therefore, miR-186-MAP3K2 may represent a new and useful potential clinical treatment and diagnosis target for NSCLC.

The role of segmental nodes in the pathological staging of non-small cell lung cancer.

BACKGROUND: Segmental nodes are not examined routinely in current clinical practice for lung cancer, the role of segmental nodes in pathological staging of non-small cell lung cancer after radical resection was investigated. METHODS: A total of 113 consecutive non-small cell lung cancer patients who underwent radical resection between June 2009 and December 2011 were retrospectively reviewed. All the operations were performed by the same group of surgeons. N2 nodes, hilar nodes, interlobar nodes and some lobar nodes were collected during surgery. The removed lung lobes were dissected routinely along lobar and segmental bronchi to collect lobar nodes and segmental nodes. The collected lymph nodes were separately labeled for histological examination. RESULTS: The detection rates of hilar nodes, interlobar nodes, lobar nodes and segmental nodes were 61.1%, 85.0%, 75.2% and 80.5%, respectively. The metastasis rates of hilar nodes, interlobar nodes, lobar nodes and segmental nodes were 5.3%, 10.5%, 16.8% and 14.2%, respectively. There were 68 cases of N0 disease, 16 cases of N1 disease and 29 cases of N2 disease. If an analysis of segmental lymph nodes had been omitted, six patients (37.5% of N1 disease) would have been down-staged to N0, and two cases of multiple-zone N1 disease would have been misdiagnosed as single-zone N1 disease, one patient would have been misdiagnosed as N2 disease with skip metastases. CONCLUSION: Segmental nodes play an important role in the accurate staging of non-small cell lung cancer, and routinely dissecting the segmental bronchi to collect the lymph nodes is feasible and may be necessary.

Complete mediastinal lymph node dissection in video-assisted thoracoscopic lobectomy versus lobectomy by thoracotomy.

BACKGROUND: Although video-assisted thoracic surgery (VATS) lobectomy has been used more and more frequently for the treatment of patients with early-stage lung cancer, controversies are mainly focused on whether the complete mediastinal lymph node dissection (MLND) can be achieved by VATS. This retrospective study aimed to compare the validity of MLND between VATS and open thoracotomy. METHODS: Patients with lung cancer were matched from a pool of pulmonary lobectomies performed by one surgeon. Patients undergoing VATS were matched with those undergoing thoracotomy in terms of gender, age, clinical tumor stage, tumor location, and surgical procedure. RESULTS: After matching, 31 patients in VATS group and 31 patients in open group were eligible for analysis. In the VATS and open groups, the mean total number of dissected lymph nodes was 28.2 ± 8.4 and 29.8 ± 11.6 (p = 0.517), respectively. In the VATS and open groups, the number of N1 nodes was 9.5 ± 4.1 and 8.4 ± 4.7 (p = 0.333), respectively. And the number of N2 nodes was also similar between the VATS and open group (18.6 ± 7.0 vs 21.4 ± 10.0, p = 0.211). No significant differences were observed between the two groups in the operating time, the blood loss, the length of chest tube drainage, the length of hospital stay, and the rate of specific complications. CONCLUSION: Our early experience suggests that, with regard to the number of the dissected lymph nodes, VATS lobectomy can achieve complete MLND, compared with the traditional approach. MLND by VATS is technically feasible and safe for early-stage lung cancer.

The accumulation and prognosis value of tumor infiltrating IL-17 producing cells in esophageal squamous cell carcinoma.

BACKGROUND: The role of IL-17 producing cells in tumors is controversial. In the present study, we investigated the prognostic value of measuring tumor-infiltrating IL-17 producing cell levels in human esophageal squamous cell carcinoma (ESCC). METHODOLOGY/PRINCIPAL FINDINGS: Immunohistochemical staining was performed to investigate the levels of IL-17+ tumor infiltrating lymphocytes (TILs), as well as CD8+ cytotoxic T lymphocytes (CTLs) and CD57+ natural killer (NK) cells from 181 ESCC patients. The prognostic value of measuring the densities of IL-17+TILs and the correlation with CTLs and NK was evaluated. IL-17 producing cells were detected in esophageal squamous cell carcinoma tissues. The IL-17 producing cells were major CD4 positive, but Foxp3 negative. The median level of IL-17+TILs was 3.90 cells/high power microscopic field (HPF). The density of IL-17 producing cells correlated negatively with T stage (P=0.042). The higher densities of tumor infiltrating IL-17+ lymphocytes were associated with better overall survival (P=0.031). Furthermore, we found that there were positive correlations between levels of IL-17 producing cells and the densities of CD8+cells, as well as CD57+cells (r=0.198, P=0.008 for CD8+ cells and r=0.261, P<0.001 for CD57+ cells, respectively). The prognosis analysis also showed that the higher levels of CD8+ CTLs and CD57+ NK cells correlated with better overall survival of ESCC patients. CONCLUSIONS: Our study suggests that tumor infiltrating IL-17 producing cells in ESCC patients may have protective roles in the tumor microenvironment and may be treated as a prognostic marker for ESCC patients.