Immune-active tumor-adjacent tissues are associated with favorable prognosis in stage I lung squamous cell carcinoma.

The immunogenomic features of tumor-adjacent lungs (TALs) in stage I lung squamous cell carcinoma (LUSC) are not clear. Multiomics analyses of tumor tissues and paired TALs from 59 stage I LUSC patients were performed. Compared to tumors, TALs exhibited a better-preserved immune contexture indicated by upregulation of immune pathways, increased immune infiltration, and higher expression of immune effector molecules. Notably, TALs had no mutations in PTEN and KEAP1, a lower incidence of human leukocyte antigen (HLA) loss and higher expression of HLA class I genes, major histocompatibility complex (MHC) I chaperones, and interferon (IFN)-γ-associated genes. Digital spatial profiling validated the generally higher immune infiltration in TALs and revealed a higher level of immune heterogeneity in LUSC tumors. Importantly, patients with higher immune infiltration in TALs had significantly longer survival, while high immune heterogeneity was associated with inferior patient survival. Our work can be considered in the selection of patients for adjuvant therapy, especially immunotherapy.

PDZ-binding kinase aggravates pancreatic neuroendocrine neoplasm progression by activating the AKT/mTOR pathway.

The therapeutic effects of existing drug regimens against pancreatic neuroendocrine neoplasms (pNENs) remain limited, and identifying ideal therapeutic targets is warranted. PDZ binding kinase (PBK) may play an oncogenic role in most solid tumors. However, its function in pNEN remains unclear. In this study, pNEN samples and International Cancer Genome Consortium data were used to determine the clinical significance of PBK. Cell counting and CCK8 assays were used to assess cell proliferation. Flow cytometry was used to assess drug-induced apoptosis and cell cycle arrest. An in vivo PBK-targeting experiment was performed in mice bearing pNENs. Western blotting, quantitative PCR, and immunohistochemistry were performed to assess the molecular mechanisms. PBK was significantly upregulated in pNEN tissues compared with paracancerous tissues. Additionally, PBK was a poor prognostic factor for pNEN patients. PBK was found to promote the proliferation of pNEN cells by activating the AKT/mTOR pathway. Furthermore, PBK inhibition combined with everolimus treatment had enhanced antitumour effects on pNEN via inhibiting AKT/mTOR pathway and inducing G0/G1 phase cell cycle arrest. This study highlights that PBK plays an oncogenic role in and is a promising therapeutic target for pNEN.

Tumor-infiltrating lymphocytes-based subtypes and genomic characteristics of EBV-associated lymphoepithelioma-like carcinoma.

Tumor-infiltrating lymphocytes (TILs) offer a key for morphological diagnosis of lymphoepithelioma-like carcinoma (LELC) and are the foundation of oncoimmunology. To date, no reports have found a specific risk stratification value of TILs and related it to genomic variation in LELC. Based on the stromal TILs (str-TILs) ratio, we classified 105 Epstein-Barr virus (EBV)-associated LELC cases into two subtypes: patients with ≥60% str-TILs area ratio in tumor were classified as subtype I, and otherwise as subtype II. Subtype I patients had significantly better progression-free survival (PFS) and overall survival (OS). We also explored the genomic characteristics of EBV-associated LELC within different involved organs. We performed whole-exome sequencing for 51 patients with enough tissue and analyzed the genomic characteristics of EBV-associated LELC. Overall, EBV-associated LELCs were characterized by a low somatic mutation rate and copy number variations; the enriched genetic lesions affected RTK-RAS, PI3K, and cell cycle pathways. Moreover, EBV-associated LELCs from different organs were more similar to each other genetically as compared with other traditional carcinomas of the same sites-as evidenced by unsupervised clustering based on the quantitative data from both mutation signature and chromosomal aneuploidies. Notably, EBV-associated LELC patients with oncogenic driver alterations showed a worse prognosis compared with patients without such alterations. © 2022 The Pathological Society of Great Britain and Ireland.

Oncogenic Alterations in Histologically Negative Lymph Nodes Are Associated with Prognosis of Patients with Stage I Lung Adenocarcinoma.

Background: Survival of patients with stage I non-small cell lung cancer (NSCLC) varies greatly. We sought to explore whether presence of oncogenic alterations in histologically-negative lymph nodes (LNs) can be of prognostic significance in stage I lung adenocarcinoma (LUAD). Methods: Genomic analysis of oncogenic alterations was applied to 123 stage I LUAD tumors. The same genomic variants identified in primary tumors were examined in corresponding histologically-negative LNs. Results: A total of 102 (82.9%) patients had at least one canonical oncogenic alteration detected in primary tumors, and 57 LNs from 12 patients (11.8%) were found to carry the identical oncogenic alterations detected in the corresponding primary tumor tissues, including EGFR mutations (six cases), KRAS mutations (three cases), ALK fusion (one case), BRAF mutation (one case) and HER2 & NRAS co-mutations (one case). None of these LNs was found to have occult tumor cells by routine pathological assessment or immunohistochemistry staining using antibodies against pan-cytokeratins (AE1/AE3) and the epithelial marker Ber-EP4. The detection rate of oncogenenic alterations in LN was significantly higher in RAS-mutant tumors than EGFR mutant tumors (36.36% verse 7.41%, p = 0.017). Patients with oncogenic alterations in LN showed inferior disease-free survival (DFS, p = 0.025) and overall survival (OS, p = 0.027). Furthermore, patients with RAS-mutations detected in LN had the worst DFS and OS (p = 0.001). Among the 11 patients with RAS mutation in primary tumors, DFS and OS in the four patients with mutations detected in LN were significantly shorter than the remaining seven patients without mutations LN (DFS, p = 0.001, OS, p = 0.002). Conclusions: Genomic analysis has the potential to detect oncogenic alterations in regional LNs for localized LUAD and presence of oncogenic alterations in regional LN may be associated with inferior clinical outcome of stage I LUAD, particularly for certain molecular subgroups. ClinicalTrials.gov ID NCT04266691.

Biodegradable iron oxide nanoparticles for intraoperative parathyroid gland imaging in thyroidectomy.

Parathyroid gland (PG) injury is the most common complication of thyroidectomy owing to the lack of approaches for surgeons to effectively distinguish PGs from surrounding thyroid glands (TGs) in the operation room. Herein, we report the development of biodegradable iron oxide nanoparticles (IONPs) as a promising contrast agent candidate for intraoperative PG visualization. We elucidated that locally administrated dark-colored IONPs readily diffuse in TGs but cannot infiltrate tissue-dense PGs, yielding a distinguishable contrast enhancement between PGs and TGs by naked eye observation. We performed unbiased and quantitative in vivo screenings to optimize particle size and concentration of IONPs for PG/TG contrast enhancement. Moreover, in vivo applications of IONPs via the local administration route demonstrate no adverse toxicities and can be biodegraded in the thyroid microenvironment within 3 months. To our knowledge, these promising findings provide the first in vivo evidence that IONPs can serve as a safe, biodegradable, and effective contrast agent candidate for improving PG visualization in thyroidectomy.

Development of a serum miRNA panel for detection of early stage non-small cell lung cancer.

Minimally invasive testing for early detection of lung cancer to improve patient survival is a major unmet clinical need. This study aimed to develop and validate a serum multi-microRNA (multimiR) panel as a minimally invasive test for early detection of nonsmall cell lung cancer (NSCLC) regardless of smoking status, gender, and ethnicity. Our study included 744 NSCLC cases and 944 matched controls, including smokers and nonsmokers, male and female, with Asian and Caucasian subjects. Using RT-qPCR and a tightly controlled workflow, we quantified the absolute expression of 520 circulating microRNAs (miRNAs) in a Chinese cohort of 180 early stage NSCLC cases and 216 healthy controls (male smokers). Candidate biomarkers were verified in two case-control cohorts of 432 Chinese and 218 Caucasians, respectively (including females and nonsmokers). A multimiR panel for NSCLC detection was developed using a twofold cross-validation and validated in three additional Asian cohorts comprising 642 subjects. We discovered 35 candidate miRNA biomarkers, verified 22 of them, and developed a five-miR panel that detected NSCLC with area under curve (AUC) of 0.936-0.984 in the discovery and verification cohorts. The panel was validated in three independent cohorts with AUCs of 0.973, 0.916, and 0.917. The sensitivity of five-miR test was 81.3% for all stages, 82.9% for stages I and II, and 83.0% for stage I NSCLC, when the specificity is at 90.7%. We developed a minimally invasive five-miR serum test for detecting early stage NSCLC and validated its performance in multiple patient cohorts independent of smoking status, gender, and ethnicity.

Non-disruptive mutation in TP53 DNA-binding domain is a beneficial factor of esophageal squamous cell carcinoma.

BACKGROUND: TP53 is frequently altered in esophageal squamous cell carcinoma (ESCC). However, the landscape of TP53 mutation and its effects on patients remain controversial. METHODS: Somatic mutations of TP53 in 161 patients with resectable ESCC were identified by next-generation sequencing (NGS) and verified by immunohistochemistry (IHC). Patients were stratified into seven TP53 mutations, and depending on the extent of the effect on the encoded protein, it was divided into "disruptive" and "non-disruptive" types. The association of TP53 mutation with clinicopathological properties and disease outcome was investigated. RESULTS: TP53 mutations were discovered in 85.7% patients, of which 68.9% carried mutations in the DNA-binding domain (DBD). A total of 47.8% and 37.9% patients had disruptive and non-disruptive TP53 mutations, respectively. Most patients carried only one TP53 mutation, but 15.5% had double mutations. TP53 mutations were dominant in exons 5 to 8. Missense mutation was the most frequent (97/163, 59.5%), and the top five frequently occurring variations included R273X, Y220X, H193, H179X, and R175H. Multivariable analysis revealed non-disruptive mutation in TP53 DBD as the independent prognostic predictor for progression-free survival (PFS) and overall survival (OS). The expression of p53 positively correlated with non-disruptive mutation in DBD. Patients with high p53 protein expression showed better outcomes. CONCLUSIONS: Non-disruptive mutation in TP53 DBD serves as an independent beneficial prognostic factor of prolonged survival in resectable ESCC.

Identification of predictors of drug sensitivity using patient-derived models of esophageal squamous cell carcinoma.

Previous studies from the Cancer Cell Line Encyclopedia (CCLE) project have adopted commercial pan-cancer cell line models to identify drug sensitivity biomarkers. However, drug sensitivity biomarkers in esophageal squamous cell carcinoma (ESCC) have not been widely explored. Here, eight patient-derived cell lines (PDCs) are successfully established from 123 patients with ESCC. The mutation profiling of PDCs can partially recapture the tumor tissue actionable mutations from 161 patients with ESCC. Based on these mutations and relative pathways in eight PDCs, 46 targeted drugs are selected for screening. Interestingly, some drug and biomarker relationships are established that were not discovered in the CCLE project. For example, CDKN2A or CDKN2B loss is significantly associated with the sensitivity of CDK4/6 inhibitors. Furthermore, both PDC xenografts and patient-derived xenografts confirm CDKN2A/2B loss as a biomarker predictive of CDK4/6 inhibitor sensitivity. Collectively, patient-derived models could predict targeted drug sensitivity associated with actionable mutations in ESCC.

A Nomogram to Predict the Pathologic Complete Response of Neoadjuvant Chemotherapy in Triple-Negative Breast Cancer Based on Simple Laboratory Indicators.

BACKGROUND: Triple-negative breast cancer (TNBC) patients who achieve a pathologic complete response (pCR) after neoadjuvant chemotherapy (NAC) have better prognoses. OBJECTIVE: This study aimed to develop an intuitive nomogram based on simple laboratory indexes to predict the pCR of standard NAC in TNBC patients. METHODS: A total of 80 TNBC patients who received eight cycles of thrice-weekly standard NAC (anthracycline and cyclophosphamide followed by taxane) and subsequently underwent surgery in Zhejiang Cancer Hospital were retrospectively enrolled, and data on their pretreatment clinical features and multiple simple laboratory indexes were collected. The optimal cut-off values of the laboratory indexes were determined by the Youden index using receiver operating characteristic (ROC) curve analyses. Forward stepwise logistic regression (likelihood ratio) analysis was applied to identify predictive factors for a pCR of NAC. A nomogram was then developed according to the logistic model, and internally validated using the bootstrap resampling method. RESULTS: pCR was achieved in 39 (48.8%) patients after NAC. Multivariate analysis identified four independent indicators: clinical tumor stage, lymphocyte to monocyte ratio, fibrinogen level, and D-dimer level. The nomogram established based on these factors showed its discriminatory ability, with an area under the curve (AUC) of 0.803 (95% confidence interval 0.706-0.899) and a bias-corrected AUC of 0.771. The calibration curve and Hosmer-Lemeshow test showed that the predictive ability of the nomogram was a good fit to actual observation. CONCLUSIONS: The nomogram proposed in the present study exhibited a sufficient discriminatory ability for predicting pCR of NAC in TNBC patients.

GAP43, a novel metastasis promoter in non-small cell lung cancer.

BACKGROUND: Brain metastasis is an extremely serious sequela with a dismal prognosis in non-small cell lung cancer (NSCLC). The present study aimed to identify novel biomarkers and potential therapeutic targets for brain metastases of NSCLC. METHODS: We performed high-throughput Luminex assays to profile the transcriptional levels of 36 genes in 70 operable NSCLC patients, among whom 37 developed brain metastases as the first relapse within 3 years after surgery. The Cox proportional hazards regression model was used to evaluate the association between genes and brain metastases. Wound healing assay and transwell assay was carried out to estimate the function of target gene in vitro. And left ventricular injection on nude mice was used to evaluate the effect of target gene in vivo. RESULTS: Growth-associated protein 43 (GAP43) was found to be related to brain metastasis. Multivariate Cox regression analysis showed that NSCLC patients with elevated GAP43 had a 3.29-fold increase in the risk for brain metastasis compared with those with low levels (95% confidence interval: 1.55-7.00; P = 0.002). Kaplan-Meier survival curves revealed that GAP43 was also associated with overall survival. Analysis of a cohort of 1926 NSCLC patients showed similar results: patients with high levels of GAP43 had worse progression-free and overall survival rates. Furthermore, in vitro experiments showed that GAP43 facilitated cell migration. Animal studies demonstrated that GAP43-silenced NSCLC cells were less likely to metastasize to the brain and bone than control cells. Immunofluorescence and F-actin/G-actin in vivo assays indicated that GAP43 knockdown triggered depolymerization of the F-actin cytoskeleton. Rho GTPase activation assays showed that Rac1 was deactivated after GAP43 was silenced. CONCLUSIONS: Our findings suggest that GAP43 is an independent predictor of NSCLC brain metastasis and that it may facilitate metastasis by regulating the Rac1/F-actin pathway.

Low Serum Levels of Pre-Surgical Total Cholesterol are Associated with Unfavorable Overall Survival in Patients with Operable Non-Small Cell Lung Cancer.

BACKGROUND: Cholesterol is an essential building block of the cell membrane and an important molecule for cell signaling and function. The dysregulation of cholesterol metabolism has been linked to several diseases, including cancer. The aim of this study is to investigate whether serum cholesterol is associated with the survival outcomes of patients with non-small cell lung cancer (NSCLC). METHODS: The concentration of total cholesterol (TC) was measured in pre-operative serum samples of 637 NSCLC patients. The associations of TC with recurrence and overall survival were analyzed using a Cox proportional hazard regression model. Kaplan-Meier survival curves were calculated for overall survival analysis. RESULTS: Our analyses showed that low serum levels of TC were associated with an increased risk of death. The association between TC and overall survival remained significant after patient age at diagnosis, gender, disease stage, histotype, tumor grade, body mass index (BMI), and smoking status were adjusted in the analysis. The patients with low serum TC had a 61% (95% confidence interval: 1.18 - 2.19) higher risk of death compared to those with normal TC. A Kaplan-Meier survival analysis showed similar results. No association was found between TC and recurrence in NSCLC. CONCLUSIONS: Our study suggests that the pre-surgical serum level of TC may be an independent prognostic indicator for NSCLC overall survival.

Tumor-Infiltrating CD4+ Lymphocytes Predict a Favorable Survival in Patients with Operable Esophageal Squamous Cell Carcinoma.

BACKGROUND The immune status within the tumor microenvironment has not been well determined in esophageal squamous cell carcinoma (ESCC). The aim of this study was to investigate the distributions of tumor-infiltrating T lymphocytes (TILs), and analyze their associations with clinical characteristics and prognosis; as well as investigate the expression of programmed death-ligand 1 (PD-L1) which has been identified as a favorable indicator of prognosis in our previous study on ESCC. MATERIAL AND METHODS Five hundred and thirty-six patients who underwent radical surgery for ESCC between January 2008 and April 2012 in Department of Thoracic Surgery at Zhejiang Cancer Hospital were included in the study. Immunohistochemistry was used to investigate the infiltration of various TILs (CD3+, CD4+, CD8+ T lymphocytes) in ESCC tissues. Chi-square test and Cox proportional hazards regression were used to explore the correlations between TILs abundance and clinicopathological variables and survival. RESULTS The infiltration of intraepithelial CD4+ (iCD4+) lymphocytes was markedly higher than it in the stromal region (44.2% for intraepithelial versus 28.9% for stromal, p<0.001). Moreover, increased iCD4+ lymphocytes were significantly associated with longer overall survival (OS, p=0.001) in univariate analysis and were identified as an independent predictor for improved OS in multivariate analysis (hazard ratio [HR]=0.67, 95% confidence interval [CI]: 0.51-0.88, p=0.040). Neither the infiltration of CD3+ nor CD8+ lymphocytes showed the prognostic value in ESCC (p>0.05). Unexpectedly, combined with our previous study results, the TILs infiltration in ESCC showed an inverse association with the expression of PD-L1 (p=0.027). CONCLUSIONS Our results suggested that iCD4+ lymphocytes infiltration could be a favorable indicator for prognosis in ESCC.

Regenerating Family Member 4 (Reg4) Enhances 5-Fluorouracil Resistance of Gastric Cancer Through Activating MAPK/Erk/Bim Signaling Pathway.

BACKGROUND Reg4, a member of the Reg multigene family, is highly upregulated in many gastrointestinal cancers including gastric cancer (GC). The enhanced expression of Reg4 is associated with the resistance of GC to 5-fluorouracil (5-FU), while the underlying mechanism is not clear. The aim of the present study was to explore the resistant mechanism underlying 5-FU resistance. MATERIAL AND METHODS Reg4 expression was assessed by Western blot analysis for SGC-7901, BGC-823, AGS, MKN28, and MKN45. Synthetic short single strand RNA oligonucleotides and Flag-Reg4 plasmid were used to investigate the biological function of Reg4 in vitro. The cell viability assay was performed by MTT. Flow cytometry was carried out to measure the apoptosis caused by 5-FU. Reverse-transcriptase quantitative polymerase chain reaction (RT-qPCR) was used to examine the expression of 5-FU metabolism related enzymes. The effect of Reg4 on intracellular signaling was evaluated by Western blot. RESULTS Western blot analysis of 5 GC cells showed that Reg4 was low or null in SGC-7901 and BGC-823, while high in AGS, MKN28, and MKN45. Over-expression of flag-Reg4 in SGC-7901 led to an increase in cell viability and lower apoptosis with 5-FU treatment. In contrast, siRNA knockdown of Reg4 enhanced 5-FU induced apoptosis. However, over-expression or knockdown of Reg4 had no significant influence on the expression of 5-FU metabolic enzymes. Further investigation revealed that Reg4 could activate Erk1/2-Bim-caspase3 cascade. CONCLUSIONS Reg4 inhibited apoptosis through regulating MAPK/Erk/Bim signaling pathway and thereby enhanced the resistance of GC to 5-FU.

Overcoming Linsitinib intrinsic resistance through inhibition of nuclear factor-κB signaling in esophageal squamous cell carcinoma.

The aim of this study is to evaluate the efficacy of insulin-like growth factor 1 receptor (IGF-1R) inhibitor Linsitinib, in esophageal squamous cell carcinoma (ESCC), and to characterize special biomarker to screen Linsitinib-sensitive patients as well as explore the molecular-resistant mechanism to Linsitinib in ESCC. Our study evaluated the sensitivity of insulin-like growth factor 1 receptor (IGF-1R) inhibitor, Linsitinib in ESCC cells with MTT assay. After Linsitinib treatment, the expressions of downstream signaling molecules and apoptosis pathways were measured by western blot. And the antitumor effect of Linsitinib and JSH-23, an inhibitor of nuclear factor-κB transcriptional activity, was analyzed both as single agent and in combination in ESCC. Apoptosis, cell viability, and clonogenic survival analysis were also investigated. The sensitivity of Linsitinib was relatively variable in patient-derived primary ESCC cells as well as in human commercial cell lines. And the downstream AKT/mTOR and ERK signaling pathways were inhibited by Linsitinib, while phosphorylation level of NF-κB p65 was obviously activated to reduce apoptosis effect in Linsitinib-resistant cell lines. Most importantly, blockage of NF-κB activity by JSH-23 could sensitize resistant cells to Linsitinib treatment. Results from this study demonstrated that the intrinsic resistance to Linsitinib was predominantly mediated by NF-κB activation in ESCC. Moreover, combination of Linsitinib and JSH-23 as therapy provides a novel strategy to overcome resistance to Linsitinib in ESCC.

The C-reactive protein/albumin ratio predicts long-term outcomes of patients with operable non-small cell lung cancer.

PURPOSE: To investigate the association between C-reactive protein/albumin ratio (CAR), an inflammation-based prognostic score, and clinicopathological factors, as well as its association with long-term outcomes in patients with operable non-small cell lung cancer (NSCLC). METHODS: A total of 617 operable NSCLC patients were retrospectively evaluated and the data of preoperative serum CRP and serum albumin was collected. The correlation between the CAR and clinicopathological factors was analyzed using the chi-square test. A Cox proportional hazards regression model was performed to evaluate the association between the CAR and outcome. RESULTS: The CAR was significantly related to sex, smoking status, BMI, histology type and clinical stage (p ≤ 0.05). The patients with characteristic of male, smoker, BMI under 18.5, squamous cell carcinoma or clinical stage III had a high level of CAR. Additionally, elevated CAR indicated a worse outcome, and the patients with higher CAR had 2.02-fold risk for disease progression (95% CI 1.48-2.74, p < 0.001) and 2.61-fold risk for death (95 % CI 2.02-3.37, p < 0.001). Multivariate analyses showed the similar results after adjusted by clinicopathological factors and another four inflammation-based prognostic scores. CONCLUSIONS: The CAR is a potential independent predictor for disease progression and death in patients with operable NSCLC.

Complement component 7 (C7), a potential tumor suppressor, is correlated with tumor progression and prognosis.

Our previous study found copy number variation of chromosome fragment 5p13.1-13.3 might involve in the progression of ovarian cancer. In the current study, the alteration was validated and complement component 7 (C7), located on 5p13.1, was identified. To further explore the clinical value of C7 in tumors, 156 malignant, 22 borderline, 33 benign and 24 normal ovarian tissues, as well as 173 non-small cell lung cancer (NSCLC) tissues along with corresponding adjacent and normal tissues from the tissue bank of Zhejiang Cancer Hospital were collected. The expression of C7 was analyzed using reverse transcriptase quantitative polymerase chain reaction. As a result, the C7 expression displayed a gradual downward trend in normal, benign, borderline and malignant ovarian tissues, and the decreased expression of C7 was correlative to poor differentiation in patients with ovarian cancer. Interestingly, a similar change of expression of C7 was found in normal, adjacent and malignant tissues in patients with NSCLC, and low expression of C7 was associated with worse grade and advanced clinical stage. Both results from this cohort and the public database indicated that NSCLC patients with low expression of C7 had a worse outcome. Furthermore, multivariate cox regression analysis showed NSCLC patients with low C7 had a 3.09 or 5.65-fold higher risk for relapse or death than those with high C7 respectively, suggesting C7 was an independent prognostic predictor for prognoses of patients with NSCLC. Additionally, overexpression of C7 inhibited colony formation of NSCLC cells, which hints C7 might be a potential tumor suppressor.

Prognostic significance of programmed death-1 and programmed death-ligand 1 expression in patients with esophageal squamous cell carcinoma.

AIMS: To evaluate the expression of programmed death-1 (PD-1) and programmed death-ligand 1 (PD-L1) and their clinical and prognostic significance in primary esophageal squamous cell carcinoma (ESCC). RESULTS: The expression rate of PD-1 and PD-L1 in ESCC was 33.5% (117/349) and 41.4% (222/536), respectively. PD-L1 expression differed significantly by tumor location, grade, lymph node metastases, and disease stage (P < 0.05). Moreover, its expression was associated with the disease free survival (DFS). Patients with positive PD-L1 expression had reduced risk for disease relapse compared to those without PD-L1 expression (Hazard ratio [HR] = 0.75, 95% confidence interval [CI]: 0.56-1.00, P = 0.048). Kaplan-Meier curves showed the similar result, P = 0.047. However, there was no significant correlation between PD-1 expression and clinicopathological factors or outcome in ESCC (P > 0.05). METHODS: The expression of PD-1 and PD-L1 was assessed by immunohistochemistry on tissue microarrays from 536 primary ESCC who underwent surgery during January 2008 and April 2012 in Zhejiang Cancer Hospital. Chi-square test and Cox proportional hazards regression were employed to analyze the associations between their expressions and clinicopathological variables and survival. CONCLUSIONS: Our results suggested that PD-L1 could be a favorable indicator of prognosis in ESCC.