Programmed death ligand-1 expression and its prognostic role in esophageal squamous cell carcinoma

Significant role of savolitinib in a case of advanced gastric cancer with abnormal mesenchymal-epithelial transition factor (MET): A case report

RATIONALE

Gastric cancer is a common and lethal malignancy worldwide. It lacks specific clinical symptoms during the early stages, and when detected, the optimal surgical opportunity is lost. Chemotherapy alone offers limited benefits in advanced inoperable disease or postoperative recurrence. Gastric cancer is a heterogeneous tumor involving multiple gene regulations; thus, multi-target combination therapy is the trend in research. The c-MET protein is a tyrosine kinase receptor belonging to the MET family, encoded by the MET proto-oncogene. After binding with its ligand, the hepatocyte growth factor, MET activates cellular signaling pathways in proliferation, motility, migration, and invasion. In addition, it may be abnormally activated in cancers via mutation, amplification, and protein overexpression.

PATIENT CONCERNS AND DIAGNOSIS

We report a 35-year-old male with advanced gastric cancer and bone metastasis who was intolerant to chemotherapy. He was in poor general condition, with thrombocytopenia and anemia.

INTERVENTIONS AND OUTCOME

Next-generation sequencing (NGS) suggested MET gene amplification in the tumor. After savolitinib treatment, the condition improved significantly without noticeable adverse reactions and maintained a progression-free status for 14 weeks.

LESSONS

This case report provides evidence for MET tyrosine kinase inhibitors in treating gastric cancer patients with MET gene amplification. It also shows that MET detection is a target in gastric cancer.

Prognostic Value of Programmed Death Ligand-1 Expression in Solid Tumors Irrespective of Immunotherapy Exposure: A Systematic Review and Meta-Analysis

BACKGROUND

The programmed cell death-1/programmed cell death ligand-1 (PD-L1) pathway, which plays a crucial role in cancer immune surveillance, is the target of several approved immunotherapeutic agents and is used as a predictive biomarker in some solid tumors. However, its use as a prognostic marker (i.e., regardless of therapy used) is not established clearly with available data demonstrating inconsistent prognostic impact of PD-L1 expression in solid tumors.

METHODS

We conducted a systematic literature search of electronic databases and identified publications exploring the effect of PD-L1 expression on overall survival and/or disease-free survival. Hazard ratios were pooled in a meta-analysis using generic inverse-variance and random-effects modeling. We used the Deeks method to explore subgroup differences based on disease site, stage of disease, and method of PD-L1 quantification.

RESULTS

One hundred and eighty-six studies met the inclusion criteria. Programmed cell death ligand-1 expression was associated with worse overall survival (hazard ratio 1.33, 95% confidence interval 1.26-1.39; p < 0.001). There was significant heterogeneity between disease sites (subgroup p = 0.002) with pancreatic, hepatocellular, and genitourinary cancers associated with the highest magnitude of adverse outcomes. Programmed cell death ligand-1 was also associated with worse overall disease-free survival (hazard ratio 1.19, 95% confidence interval 1.09-1.30; p < 0.001). Stage of disease did not significantly affect the results (subgroup p = 0.52), nor did the method of quantification via immunohistochemistry or messenger RNA (subgroup p = 0.70).

CONCLUSIONS

High expression of PD-L1 is associated with worse survival in solid tumors albeit with significant heterogeneity among tumor types. The effect is consistent in early-stage and metastatic disease and is not sensitive to method of PD-L1 quantification. These data can provide additional information for the counseling of patients with cancer about prognosis.

Clinicopathological and prognostic values of PD-L1 expression in oesophageal squamous cell carcinoma: a meta-analysis of 31 studies with 5368 patients

Several immune checkpoint inhibitors targeting programmed death ligand 1 (PD-L1)/programmed death 1 have successfully improved the prognosis of oesophageal squamous cell carcinoma (ESCC) with approval in certain countries. However, whether the expression of PD-L1 is associated with the degree of benefit is unclear yet and a unified standard of antibody and cut-off value of PD-L1 detection is also lacking. The current meta-analysis then aimed to explore the association between PD-L1 expression and clinicopathological features as well as prognosis in ESCC.A systematic search on PubMed, Embase, Cochrane Library and Web of Science databases was performed up to 30 March 2021. The correlation between PD-L1 expression and clinicopathological features, as well as prognosis in ESCC, was estimated with the random-effects model.A total of 5368 patients from 31 retrospective studies were enrolled. The overexpression of PD-L1 was significantly associated with lymph node metastasis (OR 1.342, 95% CI 0.995 to 1.809, p=0.050) and distant metastasis (OR 1.516, 95% CI 1.001 to 2.294, p=0.050). The pooled HR showed that PD-L1 overexpression was significantly correlated with poor overall survival (OS) of patients with ESCC (HR 1.306, 95% CI 1.108 to 1.539, p<0.010) but not disease-free survival (DFS) (HR 1.180, 95% CI 0.937 to 1.487, p=0.160). Heterogeneity decreased significantly in subgroup analyses. The overexpression of PD-L1 was associated with poor DFS at the cut-off point of ≥1% (HR 1.642, 95% CI 1.367 to 1.973, p<0.010; I²=0%) and worse OS at the cut-off point of ≥10% (HR 1.575, 95% CI 1.175 to 2.111, p<0.010; I²=0%).The overexpression of PD-L1 was correlated with lymph node and distant metastasis as well as poor survival of ESCC.

Ultrasensitive detection of programmed death-ligand 1 (PD-L1) in whole blood using dispersible electrodes

The direct quantification of programmed death-ligand 1 (PD-L1) as a biomarker for cancer diagnosis, prognosis and treatment efficacy is an unmet clinical need. Herein, we demonstrate the first report of rapid, ultrasensitive and selective electrochemical detection of PD-L1 directly in undiluted whole blood using modified gold-coated magnetic nanoparticles as "dispersible electrodes" with an ultralow detection limit of 15 attomolar and a response time of only 15 minutes.

Significance of druggable targets (PD-L1, KRAS, BRAF, PIK3CA, MSI, and HPV) on curatively resected esophageal squamous cell carcinoma

Background

Esophageal squamous cell carcinoma (ESCC) still remains intractable disease with few therapeutic options. Programmed death-ligand 1 (PD-L1), which is essential for immune evasion, is involved in the pathogenesis of ESCC and thus is a potential therapeutic target. PIK3CA, KRAS, and BRAF mutations, microsatellite instability (MSI) caused by deficient mismatch repair (dMMR), and human papillomavirus (HPV) can potentially upregulate PD-L1 expression, which might contribute to the clinical outcome of patients with ESCC.

Methods

We investigated the significance of the present druggable markers [PD-L1, PIK3CA, KRAS, and BRAF mutations, MSI caused by deficient dMMR, and HPV] in 64 curatively resected ESCCs, using immunohistochemistry (PD-L1 and MMR protein expression), direct sequencing (KRAS, BRAF, and PIK3CA mutations), real-time PCR (HPV infection), and MSI using quasi-monomorphic markers.

Results

PD-L1 expression, PIK3CA mutation, and MSI/dMMR were detected in 35.9, 12.5, and 17.2% of ESCCs, respectively. HPV was rarely detected (1.6%) (high-risk HPV68), whereas KRAS and BRAF mutations were not detected in ESCCs. PD-L1-positive tumors were not correlated with PIK3CA mutation or MSI/dMMR (all P > 0.05). PD-L1, PIK3CA mutation, and MSI/dMMR characterized the patients associated with light smoking, female and younger age, and younger age and well-differentiated tumors, respectively (all P < 0.05). In multivariate analysis, only PD-L1-positivity was an independent favorable prognostic factor for overall survival (OS) and disease-free survival (DFS) (P = 0.023, P = 0.014). In the PD-L1-negative ESCCs, PIK3CA mutation had a poor prognostic impact on both OS and DFS (P = 0.006, P = 0.002).

Conclusions

PIK3CA mutation may be an alternative prognostic biomarker in PD-L1-negative curatively resected ESCCs that can be optional to identify high-risk patients with worse clinical outcome who require more intensive therapy and follow-up.

MiR-212-3p mediates apoptosis and invasion of esophageal squamous cell carcinoma through inhibition of the Wnt/β-catenin signaling pathway by targeting SOX4

Background

Esophageal squamous cell carcinoma (ESCC) is the predominant subtype of esophageal cancer in East Asia, with approximately half of ESCC cases occurring in China. ESCC poses a serious threat to the quality of life of patients. MicroRNAs (miRNAs) are extremely important in the occurrence and development of ESCC. Current studies have shown that miR-212-3p is expressed at low levels in esophageal adenocarcinoma tumor tissues; however, its function and mechanism in ESCC have not been studied.

Methods

The expression levels of miR-212-3p and SOX4 were detected by quantitative polymerase chain reaction (qPCR) in ESCC tissues and adjacent tissues, and ESCC cell lines from 60 patients. The interaction of miR-212-3p and SOX4 was determined using a dual-luciferase reporter gene system. EC9706 Cells were transfected with miR-212-3p mimic, NC mimic, si-NC and si-SOX4 and miR-212-3p mimic + overexpressing-SOX4, and the effects on miR-212-3p and SOX4 expression were observed, respectively. An MTT assay was carried out to detect the proliferation ability of ESCC. The invasion ability and apoptosis level of the cells were determined by Transwell assay and flow cytometry, respectively. qPCR was used to detect expression of miR-212-3p and SOX4. Western blot was performed to observe the expression of SOX4, Wnt1, β-catenin, c-Myc, and Cyclin D1.

Results

miR-212-3P was observed to be down-regulated in ESCC tissues and cells, while SOX4 expression was up-regulated; the two were negatively correlated. The dual-luciferase reporter gene further confirmed that miR-212-3p targeted SOX4. miR-212-3p overexpression and interference with SOX4 significantly inhibited the proliferation and invasion of ESCC EC970 cells, and promoted apoptosis. Furthermore, the results of Western blot confirmed that miR-212-3p overexpression and interference with SOX4 down-regulated the expression of Wnt1, β-catenin, c-Myc, and Cyclin D1. Meanwhile, SOX4 overexpression reversed the effect of up-regulation of miR-212-3p on EC970 function.

Conclusions

miR-212-3p mediates the apoptosis and invasion of ESCC cells through inhibiting the Wnt/β-catenin signal pathway by targeting SOX4.

Programmed death ligand-1 expression in gastrointestinal cancer: Clinical significance and future challenges

Cancer immunotherapy has caused a paradigm shift from conventional therapies that directly target cancer cells to innovative therapies that utilize the host immune system. In particular, programmed cell death-1 (PD-1)/programmed death ligand-1 (PD-L1) inhibitors have achieved an impressive breakthrough and been approved for clinical use in several types of cancer including gastrointestinal (GI) cancer. To identify and develop predictive biomarkers for PD-1 inhibitors is of great concern in clinical practice. Although PD-L1 expression is considered a logical biomarker as PD-L1 is a substantial target of the immune checkpoint inhibitors, its clinical significance in GI cancer remains unclear. In this review, we summarize the current evidence for PD-L1 expression as a prognostic and predictive biomarker for PD-1/PD-L1 inhibitors in GI cancer from recent publications, and emerging evidence from recent key clinical trials on the efficacy of PD-1/PD-L1 inhibitors. Challenging clinical issues for PD-L1 assessment are then discussed from the viewpoint of the methodology for PD-L1 evaluation including the differences in PD-L1 detection assays and evaluation criteria for PD-L1 positivity. Moreover, we highlight the biological features of PD-L1 expression in terms of tumor spatial and temporal heterogeneity, which suggests important implications for biomarker analysis. Finally, we describe future perspectives using liquid biopsy for better assessment of PD-L1 status. This new information should improve our understanding of the clinical significance of PD-L1 in GI cancer, leading to optimal patient selection and treatment strategy for the clinical use of PD-1/PD-L1 inhibitors in patients with GI cancer.

Clinical Significance of Programmed Death Ligand-1 Expression in Esophageal Squamous Cell Carcinoma

BACKGROUND

The aim of this study was to evaluate the association between the expression of programmed death ligand-1 (PD-L1) and clinical outcomes in patients with surgically resected esophageal squamous cell carcinoma (ESCC).

MATERIALS AND METHODS

We included 76 patients with primary ESCC who underwent surgical resection between January 2009 and December 2014 at National Defense Medical College Hospital. Using the tumor tissues, we evaluated PD-L1 expression in tumor cells and stromal reactive lymphocytes via immunohistochemistry. Furthermore, the relationship between PD-L1 expression and the clinicopathological status of patients with ESCC was investigated.

RESULTS

PD-L1 expression in tumor cells was detected in 39.5% of the patients. In addition, 51.3% of the patients had PD-L1-positive stromal reactive lymphocytes and exhibited significantly longer overall survival than those with lack of PD-L1 expression in stromal reactive lymphocytes (median survival time, 56.0 versus 27.3 mo; log-rank test, P = 0.04). Patients with lack of PD-L1 expression in both tumor cells and stromal reactive lymphocytes showed worse overall survival than those with the PD-L1-positive expression in tumor cells and/or stromal reactive lymphocytes (P = 0.02).

CONCLUSIONS

PD-L1-positive expression in stromal reactive lymphocytes, rather than in tumor cells, is associated with a longer survival in patients with ESCC.

Significance of PD-L1 clones and C-MET expression in hepatocellular carcinoma

Programmed cell death ligand 1 (PD-L1) is an essential immune checkpoint protein implicated in immune evasion by malignant tumors. Overexpression of programmed cell death protein 1 (PD-1) and its ligand PD-L1 is associated with poor prognosis in various types of cancer. Recently, multiple advances have occurred in the area of cancer immunotherapy. Inhibiting the ligation of PD-1 by PD-L1 has been the major focus of anti-tumor immunotherapy. In diagnostic pathology, it has become crucial to detect PD-L1⁺ tumor cases using a validated immunohistochemistry (IHC) approach. Preliminary data demonstrate that C-MET promotes survival of some (e.g., renal) cancer types through regulation of PD-L1. However, C-MET expression, and its association with PD-L1, has not been well-characterized in the context of hepatocellular carcinoma (HCC), and no anti-HCC immunotherapy is currently available in Korea. Therefore, it is crucial to investigate the expression of C-MET and PD-L1, and their association with clinicopathologic factors, to facilitate the development of targeted treatments for HCC. PD-L1 expression was examined in tumor cells (TC) and immune cells (IC) of 70 patient-derived HCC specimens using IHC. Two anti-PD-L1 monoclonal antibodies (MAbs), SP263 and SP142, were utilized. Additionally, TC C-MET expression was assessed. Correlations between PD-L1 expression (as identified by both MAbs), C-MET expression and clinicopathologic factors were assessed. More PD-L1⁺ cases were identified via SP263 than via SP142 when assessing both TC and IC; in the former group, SP236 identified 14/70 positive cases, while SP142 identified only 2/70. In the latter group, SP236 identified 49/70 positive cases, while SP142 identified 30/70. Both MAbs demonstrated a higher frequency of PD-L1 expression by IC than TC. The Edmondson-Steiner grade statistically correlated with a higher frequency of SP236-detected TC PD-L1 expression. C-MET was significantly associated with advanced tumor size and was positively correlated with SP263-detected PD-L1 expression in TC. These results suggest that C-MET may serve a role in regulating PD-L1 expression in HCC. Furthermore, while SP263 generally exhibited a higher sensitivity for PD-L1 detection, concordance in PD-L1⁺ case detection between the two different MAbs was generally good. These background data may be helpful in the development of targeted anti-HCC immunotherapy focused on PD-L1 or C-MET, and in evaluating selection criteria for target populations best suited to such treatments.

From Tumor Immunology to Immunotherapy in Gastric and Esophageal Cancer

Esophageal and gastric cancers represent tumors with poor prognosis. Unfortunately, radiotherapy, chemotherapy, and targeted therapy have made only limited progress in recent years in improving the generally disappointing outcome. Immunotherapy with checkpoint inhibitors is a novel treatment approach that quickly entered clinical practice in malignant melanoma and renal cell cancer, but the role in esophageal and gastric cancer is still poorly defined. The principal prognostic/predictive biomarkers for immunotherapy efficacy currently considered are PD-L1 expression along with defects in mismatch repair genes resulting in microsatellite instability (MSI-H) phenotype. The new molecular classification of gastric cancer also takes these factors into consideration. Available reports regarding PD-1, PD-L1, PD-L2 expression and MSI status in gastric and esophageal cancer are reviewed to summarize the clinical prognostic and predictive role together with potential clinical implications. The most important recently published clinical trials evaluating checkpoint inhibitor efficacy in these tumors are also summarized.

PD-L1 expression on tumor cells associated with favorable prognosis in surgically resected esophageal squamous cell carcinoma

There is limited evidence regarding the relationship between programmed cell death ligand 1 (PD-L1) expression on tumor cells (TCs) and prognosis of esophageal squamous cell carcinoma (ESCC). This retrospective study aimed to investigate the clinical significance of PD-L1 expression in ESCC. To assess PD-L1 expression, we conducted immunohistochemistry studies using a tissue microarray encompassing 233 ESCC cases, stages I, II, and III, with detailed clinical data. PD-L1 expression on TCs was observed in 55.4% (129/233) of ESCC cases and was not associated with clinicopathological factors. ESCC patients with PD-L1-positive tumors showed significantly better overall survival and disease-free survival than did those with PD-L1-negative tumors (P = .023 and P = .026, respectively). When patients were stratified into those with stage I-II (127; 54.5%) and stage III (106; 45.5%) disease and those without (134; 57.5%) and with (99; 42.5%) lymph node metastasis, the prognostic effect was inconsistent. The overall survival and disease-free survival of patients with positive PD-L1 expression were significantly better in patients with stage I-II disease (P = .021 and P = .015, respectively) and without lymph node metastasis (P = .009 and P = .07, respectively) than their counterparts. Our results showed that PD-L1 expression on TCs was an independent predictor of prognosis of ESCC patients. However, the effect varied in patients with different stages and lymph node status. Positive PD-L1 expression was a favorable predictor in ESCC patients with stage I-II disease or without lymph node metastasis but not in patients with stage III disease or lymph node metastasis.

Prognostic significance of programmed death ligand-1 immunohistochemical expression in esophageal cancer: A meta-analysis of the literature

BACKGROUND

It is thought that expression of programmed death ligand-1 (PD-L1) in esophageal cancer (EC) might compromise patient survival. However, the association between PD-L1 expression and survival of patients with EC remains controversial.

METHODS

A meta-analysis combining eligible published studies was performed to evaluate the effect of PD-L1 expression in tumor cells detected by immunohistochemistry (IHC) on overall survival (OS) and disease-free survival (DFS) in patients with EC, using pooled hazard ratio (HR) with its 95% confidence interval (CI).

RESULTS

The pooled HR for 19 eligible studies (18 publications, n = 3306) suggested that PD-L1 overexpression had an unfavorable impact on OS (HR = 1.42, 95% CI: 1.09-1.86). No significant effect of PD-L1 overexpression on DFS was observed, and the combined HR was 1.08 (95% CI: 0.76-1.53) for 12 eligible studies (11 publications, n = 2260).

CONCLUSION

PD-L1 expression in tumor cells detected by IHC was associated with worse OS in EC. However, the prognostic value of PD-L1 expression in tumor cells on OS in EC still needs further large prospective trials to be clarified.

Clinical relevance of PD-L1 and PD-L2 overexpression in patients with esophageal squamous cell carcinoma

Background

Even with the advance of diagnosis and the treatment, the 5-year survival rate for esophageal cancer patients is still poor. The checkpoint protein inhibition provides another choice to improve the survival. The expression of the programmed death ligand-1 (PD-L1) was reported but the clinical relevance remained inconsistent in esophageal cancer. Besides, there were few references about the other ligand, programed death ligand-2 (PD-L2). In this study, we evaluated the expressions of PD-L1 and PD-L2 in patients with esophageal squamous cell carcinoma (ESCC) and assessed their clinical relevance.

Methods

From 1996 to 2011, 150 patients undergone complete surgical resection for ESCC were enrolled. Clinical data were recorded. Expression of PD-L1 and PD-L2 on cytoplasm in paraffin embedded tumor samples were analyzed by immunohistochemistry staining and scored with a semi-quantitative method.

Results

Of the patients, 96 (64.0%) patients had PD-L1 overexpression and 63 (42.0%) had PD-L2 overexpression. There was a correlation between the expression of PD-L1 and PD-L2 (P<0.001). Patients without overexpression of PD-L1, pathological T1-2 and N0 status, pathological stage I-II and no post-operative adjuvant treatment had a better disease free survival (DFS). In multivariate analysis, PD-L1 expression and pathological stage were the independent prognostic factors for DFS. The expression of PD-L2 did not influence the DFS. Although not statistically significant, patients without overexpression of PD-L1 and PD-L2 seem to have a better overall survival (OS).

Conclusions

The overexpression of PD-L1 on cytoplasm, not PD-L2, is an independent prognostic factor for DFS in patients with ESCC undergone esophagectomy. However, there is a trend which suggested that patients without overexpression of PD-L1 and PD-L2 had a better OS.

PD-L1 Expression On tumor Cells Was Associated With Unfavorable Prognosis In Esophageal Squamous Cell Carcinoma

Background: Evidence about the association between programmed cell death ligand 1 (PD-L1) expression and prognosis of esophageal squamous cell carcinoma (ESCC) were limited and controversial. Thus, the present study aims to investigate the prognostic value of tumor immune microenvironment (TIM) based on PD-L1 expression and CD8+ T cell infiltration in ESCC tissues.

Methods: From September 2008 to March 2010, a total of 146 ESCC patients received radical esophagectomy were retrospectively analyzed in our present study. PD-L1 expression and CD8+ T cell infiltration were evaluated through immunohistochemistry. The clinicopathological characteristics and survival were analyzed.

Results: There were 111 male and 35 female. The median age was 59.1 years (37-78 years). The positive rate of PD-L1 expression was 61.7%. The rate of high CD8+ T cell infiltration was 33%. No significant differences were found between clinicopathological features and PD-L1 expression or CD8+ T cell infiltration. PD-L1 expression was significantly associated with poor overall survival (P=0.010). However, CD8+ T cell infiltration was not a prognostic risk factor. Type of TIM was significantly associated with the prognosis of ESCC patients (P=0.021).

Conclusions: PD-L1 expression was an independent risk factor for the prognosis of ESCC patients. Immunotherapy may achieve promising outcomes in ESCC patients with type I TIM.

Prognostic value of PD-L1 in esophageal squamous cell carcinoma: a meta-analysis

Accumulated evidence has shown that the programmed cell death receptor 1/programmed cell death receptor 1 ligand 1 (PD-1/PD-L1) pathway is a promising therapeutic target for cancer immunotherapy. However, the association between PD-L1 and esophageal squamous cell carcinoma (ESCC) patient survival remains unclear. We performed a meta-analysis to investigate the prognostic value of PD-L1 in ESCC. We searched PubMed, Embase, Web of Knowledge, and Cochrane Central Register of Controlled Trials databases for relevant studies that evaluated PD-L1 expression and ESCC patient survival. Fixed- and random-effects meta-analyses were conducted according to the heterogeneity of the included studies. Sensitivity analysis was performed according to Metan-based influence analysis. Publication bias was evaluated using Egger's and Begg's tests. Overall, 13 studies with 2,877 patients were included. Twelve studies demonstrated the association between overall survival (OS), and 6 studies described the relation between disease-free survival (DFS). PD-L1 overexpression was found in 43.7% (1,258 of 2,877) of the patients with ESCC. High PD-L1 expression was associated with distant metastasis in patients with ESCC (P = 0.04). Moreover, high PD-L1 expression was significantly associated with poor OS (hazard ratio [HR] 1.38, 95% confidence interval [CI] = 1.02-1.86, P = 0.04) and especially in Asian populations (HR 1.49, 95% CI = 1.11-1.99, P = 0.008). But it did not have an impact on disease-free survival (HR 1.15, 95% CI = 0.76-1.74, P = 0.52). Further well-designed clinical studies with uniform assessment approaches for PD-L1 expression are warranted to verify its prognostic value.

Expression, regulation and targeting of receptor tyrosine kinases in esophageal squamous cell carcinoma

Esophageal cancer is one of the most common types of cancer, which is a leading cause of cancer-related death worldwide. Based on histological behavior, it is mainly of two types (i) Esophageal squamous cell carcinoma (ESCC), and (ii) esophageal adenocarcinoma (EAD or EAC). In astronomically immense majority of malignancies, receptor tyrosine kinases (RTKs) have been kenned to play a consequential role in cellular proliferation, migration, and metastasis of the cells. The post-translational modifications (PTMs) including phosphorylation of tyrosine (pY) residue of the tyrosine kinase (TK) domain have been exploited for treatment in different malignancies. Lung cancer where pY residues of EGFR have been exploited for treatment purpose in lung adenocarcinoma patients, but we do not have such kind of felicitously studied and catalogued data in ESCC patients. Thus, the goal of this review is to summarize the studies carried out on ESCC to explore the role of RTKs, tyrosine kinase inhibitors, and their pertinence and consequentiality for the treatment of ESCC patients.

Expression, regulation and targeting of receptor tyrosine kinases in esophageal squamous cell carcinoma

Esophageal cancer is one of the most common types of cancer, which is a leading cause of cancer-related death worldwide. Based on histological behavior, it is mainly of two types (i) Esophageal squamous cell carcinoma (ESCC), and (ii) esophageal adenocarcinoma (EAD or EAC). In astronomically immense majority of malignancies, receptor tyrosine kinases (RTKs) have been kenned to play a consequential role in cellular proliferation, migration, and metastasis of the cells. The post-translational modifications (PTMs) including phosphorylation of tyrosine (pY) residue of the tyrosine kinase (TK) domain have been exploited for treatment in different malignancies. Lung cancer where pY residues of EGFR have been exploited for treatment purpose in lung adenocarcinoma patients, but we do not have such kind of felicitously studied and catalogued data in ESCC patients. Thus, the goal of this review is to summarize the studies carried out on ESCC to explore the role of RTKs, tyrosine kinase inhibitors, and their pertinence and consequentiality for the treatment of ESCC patients.

Role of PD-L1 expression as a biomarker for GEP neuroendocrine neoplasm grading

Neuroendocrine neoplasms (NENs) are rare, heterogeneous and ubiquitous tumors commonly localized in the gastrointestinal tract, lung, and pancreas. The clinical behavior of NEN is highly unpredictable; in fact, low-grade cases can unexpectedly be associated with metastases. Currently, the 2010 WHO NEN classification employs histological differentiation and the proliferation index for grading tumors but fails to provide reliable prognostic and therapeutic indications. Therefore, there is an urgent need for a better characterization of G2/G3 NENs. Similar to several other tumors, NENs possess immune-escape mechanisms, but very little has yet been done to characterize this crucial aspect. There are no available data describing PD-L1 expression in these tumors. Here we provide, for the first time, evidence of PD-L1 tissue expression in gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs). PD-L1 expression was significantly associated with a high-grade WHO classification (G3) (P<0.001) but not with gender, primary site, or lymph node status. The PD-L1 positivity rate and signal intensity are directly correlated (P<0.001) with a grade increase from G1 to G3. In particular in G3 cases, we observed a dichotomy between the morphology (WD- and PD-NENs) and Ki67. Moreover, our study demonstrated a significant association with the grade and PD-L1 expression levels in immune-infiltrating cells (P<0.001). In particular, G3 tumors are characterized by strong PD-L1 expression in both the tumor and infiltrating immune cells (P<0.001), reflecting an unfavorable environment for T-cell-mediated tumor aggression. These findings suggest that NENs might acquire resistance to immune surveillance by upregulating PD-L1 and inhibiting peritumoral and intratumoral infiltrating lymphocytes. Here we demonstrate that PD-L1 is currently the best-known biomarker for G3 NENs, becoming the new gold standard for G3 NEN discrimination. Furthermore, pharmacological approaches using anti-PD-1 antibodies may become the logical choice for the treatment of G3 cases with a poor prognosis.

MACC1 induces autophagy to regulate proliferation, apoptosis, migration and invasion of squamous cell carcinoma

Metastasis-associated colon cancer-1 (MACC1) plays an important role in cancer development, but the role and mechansim of MACC1 in squamous cell carcinoma (ESCC) remain unclear. In this study, we found that MACC1 expression was increased in ESCC, and correlated with lymph node metastasis. MACC1 knockdown suppresed ESCC cell proliferation, metastasis and enchanced cell apoptosis. Moreover, MACC1 knockdown inhibited ESCC cell autophagy, and 3-methyladenine was able to rescue MACC1-induced malignant phenotype of ESCC cells. Furthermore, MACC1 knockdown inactivated AMPK-ULK1 signaling pathway, and metformin could rescue MACC1-induced autophagy in ESCC cells. Collectively, this study found that upregulation of MACC1 in ESCC was associated with lymph node metastasis of patients, and MACC1 regulated ESCC cell proliferation, apoptosis, migration and invasion mainly through AMPK-ULK1 induced autophagy.

Programmed death ligand-1 and MET co-expression is a poor prognostic factor in gastric cancers after resection

Programmed death-ligand 1 (PD-L1) plays an essential protein for immune evasion, contributing to tumor development and progression. Recent studies have reported MET as an upregulator for PD-L1 overexpression through an oncogenic pathway. However, an association between PD-L1 expression with MET has not been reported in gastric cancer.The prognostic significance of PD-L1 and its association with Epstein-Barr virus (EBV), microsatellite instability (MSI), and mucin phenotype remain controversial. We performed in situ hybridization for EBV-encoded RNA and immunohistochemistry in tissue microarrays for 394 gastric cancers. A multiplex polymerase chain reaction with five quasimonomorphic markers was performed for MSI. PD-L1 expression was observed in 123 cases (31.2%), and clinicopathological features such as MET overexpression, high pT stage, and a lack of lymphatic invasion represent significant risk factors associated with PD-L1 overexpression in gastric cancers. No associations of EBV, MSI, or mucin phenotype with PD-L1 expression were statistically significant. PD-L1 expression was a strong indicator for worse overall survival (OS) but borderline significant in disease-free survival (DFS). A combined analysis of PD-L1 and MET expression indicated that the PD-L1+/MET+ subgroup showed the worst prognosis when compared to the PD-L1-/MET- subgroup, which had the best clinical outcome. Furthermore, PD-L1 overexpression exhibited poor prognosis in terms of both OS and DFS in EBV-negative, microsatellite stable, and intestinal mucin phenotype tumors. In conclusion, this is the first study to evaluate the overexpression of MET as a risk factor for PD-L1 positivity in gastric cancer tissue as well as the reliability and prognostic relevance of PD-L1/MET co-expression after surgery.