The expression of PD-L1 protein as a prognostic factor in lung squamous cell carcinoma

Clinical significance of CD155 expression in surgically resected lung squamous cell carcinoma

BACKGROUND

Cluster of differentiation 155 (CD155) is expressed in many tumor types. CD155 is involved in the immune avoidance of tumor cells and contributes to tumor development and progression. Therefore, CD155 is a novel target for cancer immunotherapy. The clinical significance of CD155 expression in lung squamous cell carcinoma (LUSC) has not been fully elucidated.

MATERIALS AND METHODS

We performed a retrospective analysis of 264 patients with surgically resected LUSC. Immunohistochemistry was used to evaluate CD155 expression. The association of CD155 expression with clinicopathological features and clinical outcomes was assessed. We also analyzed the relationship between CD155 expression and programmed cell death-ligand 1 (PD-L1) expression and tumor-infiltrating lymphocytes.

RESULTS

Among the 264 patients, 137 patients (51.9%) were classified in the high CD155 expression group. High CD155 expression was significantly associated with pleural invasion, vascular invasion, PD-L1 positivity, and high CD3, CD4, and CD8 expressions. In multivariate analysis, the presence of pleural invasion and PD-L1 positivity were independent predictors of high CD155 expression. Kaplan-Meier curve analysis showed that high CD155 expression was significantly associated with shorter disease-free survival and overall survival. In multivariate analysis, high CD155 expression was an independent poor prognostic factor for overall survival, but not for disease-free survival. Subgroup analyses revealed that the prognostic effect of CD155 expression was observed in the PD-L1 positive group but not the PD-L1 negative group.

CONCLUSION

Our analysis revealed that high CD155 expression significantly predicted poor prognosis in patients with surgically resected LUSC, especially in patients with PD-L1-positive tumors.

Clinical Significance of SIRPα Expression on Tumor-Associated Macrophages in Patients with Lung Squamous Cell Carcinoma

BACKGROUND

Signal-regulatory protein alpha (SIRPα) is an immune checkpoint molecule expressed on macrophages that functions to inhibit phagocytosis by binding to CD47 expressed on tumor cells. SIRPα has attracted increasing attention as a novel target for cancer immunotherapy; however, the expression and immune function of SIRPα in lung squamous cell carcinoma (LUSC) remain unclear. Therefore, this study aimed to identify the clinical importance of SIRPα expression in LUSC and to explore the factors that elevate SIRPα expression.

PATIENTS AND METHODS

Primary LUSC specimens surgically resected from 172 patients underwent immunohistochemical evaluation of the association of SIRPα expression on tumor-associated macrophages with clinicopathological features and clinical outcomes. Furthermore, we analyzed the association of SIRPα expression with tumor-infiltrating lymphocytes and the expression of programmed cell death ligand 1 (PD-L1). In vitro, monocytes were treated with cytokines, and SIRPα protein expression was assessed by flow cytometry.

RESULTS

There were no differences in SIRPα expression and clinicopathological factors. High SIRPα expression was significantly associated with PD-L1-positive expression, and high CD8, PD-1, and CD163 expression. The high SIRPα expression group showed significantly shorter recurrence-free survival (RFS) and overall survival (OS). On multivariate analysis, high SIRPα expression was an independent poor prognostic factor for RFS and OS. The expression of SIRPα protein in monocytes was upregulated by treatment with IFNγ.

CONCLUSION

Our analysis revealed that high SIRPα expression significantly predicts poor prognosis in patients with surgically resected LUSC.

Sumo-regulatory SENP2 controls the homeostatic squamous mitosis-differentiation checkpoint

Squamous or epidermoid cancer arises in stratified epithelia but also is frequent in the non-epidermoid epithelium of the lung by unclear mechanisms. A poorly studied mitotic checkpoint drives epithelial cells bearing irreparable genetic damage into epidermoid differentiation. We performed an RNA-sequencing gene search to target unknown regulators of this response and selected the SUMO regulatory protein SENP2. Alterations of SENP2 expression have been associated with some types of cancer. We found the protein to be strongly localised to mitotic spindles of freshly isolated human epidermal cells. Primary cells rapidly differentiated after silencing SENP2 with specific shRNAs. Loss of SENP2 produced in synchronised epithelial cells delays in mitotic entry and exit and defects in chromosomal alignment. The results altogether strongly argue for an essential role of SENP2 in the mitotic spindle and hence in controlling differentiation. In addition, the expression of SENP2 displayed an inverse correlation with the immuno-checkpoint biomarker PD-L1 in a pilot collection of aggressive lung carcinomas. Consistently, metastatic head and neck cancer cells that do not respond to the mitosis-differentiation checkpoint were resistant to depletion of SENP2. Our results identify SENP2 as a novel regulator of the epithelial mitosis-differentiation checkpoint and a potential biomarker in epithelial cancer.

Progress of immune checkpoint inhibitors therapy for non-small cell lung cancer with liver metastases

Nearly one-fifth of patients with non-small cell Lung Cancer (NSCLC) will develop liver metastases (LMs), and the overall treatment strategy of LMs will directly affect the survival of patients. However, some retrospective studies have found that patients receiving chemotherapy or targeted therapy have a poorer prognosis once LMs develop. In recent years, multiple randomised controlled trials (RCTS) have shown significant improvements in outcomes for patients with advanced lung cancer following the introduction of immune checkpoint inhibitors (ICIs) compared to conventional chemotherapy. ICIs is safe and effective in patients with LMs, although patients with LMs are mostly underrepresented in randomised clinical trials. However, NSCLC patients with LMs have a significantly worse prognosis than those without LMs when treated with ICIs, and the mechanism by which LMs induce systemic anti-tumour immunity reduction is unknown, so the management of LMs in patients with NSCLC is a clinical challenge that requires more optimised therapies to achieve effective disease control. In this review, we summarised the mechanism of ICIs in the treatment of LMs, the clinical research and treatment progress of ICIs and their combination with other therapies in patients with LMs from NSCLC.

Effects of EGFR driver mutations on pathologic regression in resectable locally advanced non-small cell lung cancer treated with neoadjuvant chemoradiation and completion surgery

OBJECTIVE

We hypothesized that driver mutations in epidermal growth factor receptor (EGFR) are associated with decreased pathologic response to neoadjuvant chemoradiation (NA-ChRT) in locally advanced non-small cell lung cancer (LA-NSCLC).

METHODS

Patients with Stage IIB-IIIA NSCLC treated with NA-ChRT, completion surgery, and underwent molecular profile testing were identified in a lung cancer database. Pathologic response was quantified using: (i) major pathologic response (MPR), (ii) complete pathologic response (pCR), and (iii) mean residual viable tumor cells (MRTC). Two groups were formed based on the presence or absence of driver mutations. Clinical and pathological correlations between the groups were studied.

RESULTS

Forty-seven patients underwent tumor molecular profile testing, NA-ChRT, and completion surgery. Compared to the no-driver mutation group, the driver mutation group had lower MPR (23% vs 71%, p = 0.003), pCR (0% vs 26%, p = 0.02), and higher MRTC (43.4% vs 15.8%, p = 0.009). Univariate analysis showed an increased MPR rate for smokers, squamous cell histology, ChRT-surgery interval >65 days, and no-driver mutations. Multivariate analysis showed that only no-driver mutations (OR 0.39, p = 0.02) remained significant for MPR. PD-L1 status did not affect MPR. At 2 years, the driver mutation group had lower rates of local control (Hazard ration [HR] 0.67, p = 0.17) and disease-free survival (HR 0.5, p = 0.001). Overall survival was similar for both groups (HR = 1.04, p = 0.86).

CONCLUSION

Following 60 Gray NA-ChRT, tumors with a driver mutation had lower MPR and pCR rates than tumors without a driver mutation. PD-L1 was not associated with tumor regression.

ADVANCES IN KNOWLEDGE

Patients with resectable LA-NSCLC and an EGFR driver mutation treated with neoadjuvant-ChRT and completion surgery have reduced pathologic regression, lower local control rates, and shorter disease-free survival than patients without a driver mutation. Evaluation of molecular testing should be introduced in LA-NSCLC intended for prognostication and treatment decisions.

Progress of immune checkpoint inhibitors therapy for non-small cell lung cancer with brain metastases

About 40% of patients with non-small cell lung cancer (NSCLC) develop brain metastases (BMs) throughout the disease, and the occurrence of BMs is considered to have a fairly high mortality rate. Therefore, the management of brain metastases in NSCLC patients is a clinical challenge. Currently, multidisciplinary diagnosis and treatment methods are often used to achieve effective control of intracranial disease and prolong survival. Immunotherapy (IT) is one of the core therapies for NSCLC. Single or combined IT represented by immune checkpoint inhibitors(ICIs) of programmed death-1(PD-1)/ programmed cell death-ligand 1 (PD-L1) can significantly improve the prognosis of patients with advanced NSCLC.ICIs has been shown to be safe and effective in patients with BMs, although patients with BMs are mostly underrepresented in randomized clinical trials. In this review, we summarized the mechanism of ICIs in the treatment of BMs, and the clinical research and treatment progress of ICIs and their combination with other therapies in patients with BMs s from NSCLC.

A Review of Biomarkers and Their Clinical Impact in Resected Early-Stage Non-Small-Cell Lung Cancer

The postoperative survival of early-stage non-small-cell lung cancer (NSCLC) patients remains unsatisfactory. In this review, we examined the relevant literature to ascertain the prognostic effect of related indicators on early-stage NSCLC. The prognostic effects of the epidermal growth factor receptor (EGFR), anaplastic lymphoma kinase (ALK), mesenchymal-epithelial transition (MET), C-ros oncogene 1 (ROS1), or tumour protein p53 (TP53) alterations in resected NSCLC remains debatable. Kirsten rat sarcoma viral oncogene homologue (KRAS) alterations indicate unfavourable outcomes in early-stage NSCLC. Meanwhile, adjuvant or neoadjuvant EGFR-targeted agents can substantially improve prognosis in early-stage NSCLC with EGFR alterations. Based on the summary of current studies, resected NSCLC patients with overexpression of programmed death-ligand 1 (PD-L1) had worsening survival. Conversely, PD-L1 or PD-1 inhibitors can substantially improve patient survival. Considering blood biomarkers, perioperative peripheral venous circulating tumour cells (CTCs) and pulmonary venous CTCs predicted unfavourable prognoses and led to distant metastases. Similarly, patients with detectable perioperative circulating tumour DNA (ctDNA) also had reduced survival. Moreover, patients with perioperatively elevated carcinoembryonic antigen (CEA) in the circulation predicted significantly worse survival outcomes. In the future, we will incorporate mutated genes, immune checkpoints, and blood-based biomarkers by applying artificial intelligence (AI) to construct prognostic models that predict patient survival accurately and guide individualised treatment.

Prognostic implication of PD-L1 in early-stage non-small cell lung cancer: a retrospective single-centre study

BACKGROUND

The prognostic role of programmed death-ligand 1 (PD-L1) expression in patients with localised and locally advanced non-small cell lung cancer has not been fully elucidated. This information could help to better interpret recent and upcoming results of phase III adjuvant or neoadjuvant anti-PD-1/PD-L1 immunotherapy studies.

METHODS

In a cohort of 146 patients with early or locally advanced non-small cell lung cancer treated with curative intent (by surgery or radiotherapy), we investigated the prognostic value of PD-L1 expression and its correlation with other biological and clinical features. PD-L1 expression was stratified by quartiles. Primary endpoints were overall and disease-free survival. We also analysed the prognostic impact of the presence of actionable mutations, implemented treatment modality and completion of the treatment plan. Neither type of patient received neoadjuvant or adjuvant immunotherapy or target therapy.

RESULTS

Of the 146 selected patients, 32 (21.9%) presented disease progression and 15 died (10.3%) at a median follow-up of 20 months. In a univariable analysis, PD-L1 expression ≥25% was associated with significantly lower disease-free survival (hazard ratio [HR]) 1.9, 95% confidence interval [CI] 1.0-3.9, p = 0.049). PD-L1 expression ≥50% did not lead to disease-free survival or overall survival benefits (HR 1.2 and 1.1, respectively; 95% CI 0.6-2.6 and 0.3-3.4, respectively; pnot significant). In a multivariate analysis, a stage >I (HR 2.7, 95% CI 1.2-6, p = 0.012) and having an inoperable tumour (HR 3.2, 95% CI 1.4-7.4, p = 0.005) were associated with lower disease-free survival.

CONCLUSION

The population of patients with early-stage non-small cell lung cancer and PD-L1 expression ≥25% who were treated with curative intent during the pre-immunotherapy era exhibited a worse prognosis. This finding provides justification for the utilisation of adjuvant immunotherapy in this subgroup of patients, based on the current evidence derived from disease-free survival outcomes. However, for patients with PD-L1 expression <25%, opting to wait for the availability of the overall survival results may be a prudent choice.

Significance of programmed death-ligand 1 expression in resected lung cancer and its relationship with EGFR mutation

BACKGROUND

Several studies have reported that the high expression of programmed death-ligand 1 (PD-L1) within tumor cells predicts a poor prognosis. However, the relationship between the PD-L1 expression and lymph node metastasis or driver mutations in lung cancer remains poorly understood.

METHODS

A total of 356 consecutive patients who underwent surgical resection for primary lung cancer were included in the study. There were 268 adenocarcinomas including 100 EGFR mutations, 67 squamous cell carcinomas (Sq), and 21 other histologies. The high expression of PD-L1 was defined as a tumor proportion score (TPS) of ≥50. The relationship between the PD-L1 expression and clinicopathological factors and recurrence-free survival (RFS) was analyzed.

RESULTS

The PD-L1 expression was high in 75 patients. It was significantly related to smoking history, Sq histology, driver mutation negative, elevated serum carcinoembryonic antigen levels, and lymph node metastasis. Among patients with driver mutations, a high PD-L1 TPS was found in patients with EGFR G719X mutation. A significant difference in RFS was observed in adenocarcinoma patients. A multivariate analysis of adenocarcinoma cases revealed that tumor size and lymph node metastasis were independent prognostic factors for poor RFS, while the PD-L1 expression was not. A logistic regression analysis revealed that the absence of driver mutations, lymph node metastasis, and a history of smoking were significantly associated with the high expression of PD-L1.

CONCLUSION

Lymph node metastasis was positively related with the high expression of PD-L1, resulting in poor RFS. A high PD-L1 TPS was observed in patients with the EGFR G719X mutation.

Let-7a/cMyc/CCAT1/miR-17-5p Circuit Re-sensitizes Atezolizumab Resistance in Triple Negative Breast Cancer through Modulating PD-L1

BACKGROUND

Triple negative breast cancer (TNBC) is an immunogenically hot tumor. The immune checkpoint blockades (ICBs) have been recently emerged as promising therapeutic candidates for several malignancies including TNBC. Yet, the development of innate and/or adaptive resistance by TNBC patients towards ICBs such as programmed death-ligand 1 (PD-L1) inhibitors (e.g. Atezolizumab) shed the light on importance of identifying the underlying mechanisms regulating PD-L1 in TNBC. Recently, it was reported that non-coding RNAs (ncRNAs) perform a fundamental role in regulating PD-L1 expression in TNBC. Hence, this study aims to explore a novel ncRNA axis tuning PD-L1 in TNBC patients and investigate its possible involvement in fighting Atezolizumab resistance.

METHODS

In-silico screening was executed to identify ncRNAs that could potentially target PD-L1. Screening of PD-L1 and the nominated ncRNAs (miR-17-5p, let-7a and CCAT1 lncRNA) was performed in BC patients and cell lines. Ectopic expression and/or knockdown of respective ncRNAs were performed in MDA-MB-231. Cellular viability, migration and clonogenic capacities were evaluated using MTT, scratch assay and colony-forming assay, respectively.

RESULTS

PD-L1 was upregulated in BC patients, especially in TNBC patients. PD-L1 is positively associated with lymph node metastasis and high Ki-67 in recruited BC patients. Let-7a and miR-17-5p were nominated as potential regulators of PD-L1. Ectopic expression of let-7a and miR-17-5p caused a noticeable reduction in PD-L1 levels in TNBC cells. In order to investigate the whole ceRNA circuit regulating PD-L1 in TNBC, intensive bioinformatic studies were performed. The lncRNA, Colon Cancer-associated transcript 1 (CCAT1), was reported to target PD-L1 regulating miRNAs. Results showed that CCAT1 is an upregulated oncogenic lncRNA in TNBC patients and cell lines. CCAT1 siRNAs induced a noticeable reduction in PD-L1 levels and a marked increase in miR-17-5p level, building up a novel regulatory axis CCAT1/miR-17-5p/PD-L1 in TNBC cells that was tuned by the let-7a/c-Myc engine. On the functional level, co-treatment of CCAT-1 siRNAs and let-7a mimics efficiently relieved Atezolizumab resistance in MDA-MB-231 cells.

CONCLUSION

The present study revealed a novel PD-L1 regulatory axis via targeting let-7a/c-Myc/CCAT/miR-17-5p. Additionally, it sheds the light on the potential combinational role of CCAT-1 siRNAs and Let-7a mimics in relieving Atezolizumab resistance in TNBC patients.

Clinical significance of the combination of preoperative SUVmax and CEA in patients with clinical stage IA lung adenocarcinoma

BACKGROUND

Preoperative maximum standardized uptake value (SUVmax) of 2-[18F]-fluoro-2-deoxy-D-glucose positron emission tomography and serum carcinoembryonic antigen (CEA) have been reported as prognostic factors for lung adenocarcinoma. However, the significance of combined SUVmax and CEA in early-stage lung adenocarcinoma is not well known.

METHODS

We retrospectively evaluated the relationship between the combination of SUVmax and CEA and the prognosis of 410 patients with clinical stage IA lung adenocarcinoma who underwent resection. The cutoff values for SUVmax and CEA were determined by receiver operating characteristic curve analysis, and patients were categorized into high SC (SUVmax and CEA) group (SUVmax ≥2.96 and CEA ≥5.3), moderate SC group (either SUVmax <2.96 and CEA ≥5.3 or SUVmax ≥2.96 and CEA <5.3) and low SC group (SUVmax <2.96 and CEA <5.3).

RESULTS

Kaplan-Meier curve analysis showed that patients with clinical stage IA lung adenocarcinoma in the high SC group had significantly shorter overall survival (OS) and recurrence-free survival (RFS) than the other groups (p = 0.011 and p < 0.0001, respectively). Multivariate analysis showed that high SC was an independent prognostic factor of OS (p = 0.029) and RFS (p < 0.0001).

CONCLUSIONS

High values of SUVmax and CEA were associated with poor OS and RFS in patients with stage IA lung adenocarcinoma. Simultaneous evaluation of SUVmax and CEA may be an effective prognostic marker to determine the optimal treatment strategy of early-stage lung adenocarcinoma.

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.

Clinical and Prognostic Value of Antigen-Presenting Cells with PD-L1/PD-L2 Expression in Ovarian Cancer Patients

The latest literature demonstrates the predominant role of the programmed cell death axis (PD-1/PD-L1/PD-L2) in ovarian cancer (OC) pathogenesis. However, data concerning this issue is ambiguous. Our research aimed to evaluate the clinical importance of PD-L1/PD-L2 expression in OC environments. We evaluated the role of PD-L1/PD-L2 in OC patients (n = 53). The analysis was performed via flow cytometry on myeloid (mDCs) and plasmacytoid dendritic cells (pDCs) and monocytes/macrophages (MO/MA) in peripheral blood, peritoneal fluid (PF), and tumor tissue (TT). The data were correlated with clinicopathological characteristics and prognosis of OC patients. The concentration of soluble PD-L1 (sPD-L1) and PD-1 in the plasma and PF were determined by ELISA. We established an accumulation of PD-L1+/PD-L2+ mDCs, pDCs, and MA in the tumor microenvironment. We showed an elevated level of sPD-L1 in the PF of OC patients in comparison to plasma and healthy subjects. sPD-L1 levels in PF showed a positive relationship with Ca125 concentration. Moreover, we established an association between higher sPD-L1 levels in PF and shorter survival of OC patients. An accumulation of PD-L1+/PD-L2+ mDCs, pDCs, and MA in the TT and high sPD-L1 levels in PF could represent the hallmark of immune regulation in OC patients.

PD-L1 Protein Expression and Gene Amplification Correlate with the Clinicopathological Characteristics and Prognosis of Lung Squamous Cell Carcinoma

Purpose

To investigate PD-L1 protein expression and gene amplification in lung squamous cell carcinoma (LUSC) and analyse their correlation with the clinicopathological characteristics and prognosis of LUSC patients.

Patients and Methods

Tissue samples from 164 LUSC patients were collected. PD-L1 protein was detected by immunochemistry (IHC), and PD-L1 gene amplification was investigated by fluorescence in situ hybridization in LUSC patients.

Results

The positive expression rate of PD-L1 in LUSC was 47.6% (78/164), and the amplification rate of PD-L1 was 6.7% (11/164); both rates were higher than those of paratumor tissue. Both PD-L1 positive expression and gene amplification were correlated with clinical stage and lymph node metastasis (P<0.05). PD-L1 protein expression, PD-L1 gene amplification, late stage, lymph node metastasis and distant metastasis were significantly correlated with the prognosis of patients. Among these factors, late stage, lymph node metastasis, PD-L1 protein expression and PD-L1 gene amplification were independent prognostic factors for LUSC.

Conclusion

Positive PD-L1 protein expression and gene amplification are involved in the malignant progression and metastasis of LUSC. Both PD-L1 protein expression and gene amplification are associated with poor prognosis.

PDL-1 expression in lung carcinoma and its correlation with clinicopathological and prognostic characteristics

Lung cancers have high incidence and high mortality rates. The immune checkpoints as programmed death ligand 1 (PDL-1) can suppress the tumor immune reaction. So, their blocking seems to be a way to treat tumors. This study assesses PDL-1 immunohistochemical expression in lung cancer, and its correlation with prognosis. It included 62 specimens of lung cancer in Hospitals of Mansoura Faculty of Medicine, Egypt. Seventy-one percent of cases showed positive PDL-1 and about 59.1% of them showed high expression. PDL-1 expression in NSCLC was significantly higher than in SCLC (P = 0.019). There were no significant associations between PDL-1 expression and other clinicopathological parameters. A significant mild positive correlation between PDL-1 and EGFR marker was found (P = 0.006). The mean overall survival in cases with positive PDL-1 was lower than negative cases (P = 0.37). Also, progression-free survival was lower among PDL-1 positive cases compared to negative cases (P = 0.5). This study reports that immune checkpoint, PDL-1 is overexpressed in lung cancer especially NSCLC. It is correlated with EGFR overexpression. PDL-1 could have potential to be an effective immune target for lung cancer immunotherapy. But the presence of PD-L1-negative tumors highlights the importance of searching for alternative or combination treatment strategies.Abbreviations: AC: Adenocarcinoma; COPD: Chronic Obstructive Pulmonary Diseases; CTLA-4: Cytotoxic T-lymphocyte-associated protein 4; EGFR: Epidermal Growth Factor Receptor; IHC: Immunohistochemical; NSCLC: Non-Small Cell Lung Cancer; OS: Overall Survival; PD1: Programmed Death 1; PDL-1: Programmed Death ligand 1; PFS: Progression Free Survival; SCC: Squamous cell carcinoma; SCLC: Small Cell Lung Cancer; SD: Standard Deviation; TCR: T-cell receptor; TPS: Tumor Proportion Score.

Non-invasive measurement of PD-L1 status and prediction of immunotherapy response using deep learning of PET/CT images

BACKGROUND

Currently, only a fraction of patients with non-small cell lung cancer (NSCLC) treated with immune checkpoint inhibitors (ICIs) experience a durable clinical benefit (DCB). According to NCCN guidelines, Programmed death-ligand 1 (PD-L1) expression status determined by immunohistochemistry (IHC) of biopsies is the only clinically approved companion biomarker to trigger the use of ICI therapy. Based on prior work showing a relationship between quantitative imaging and gene expression, we hypothesize that quantitative imaging (radiomics) can provide an alternative surrogate for PD-L1 expression status in clinical decision support.

METHODS

18F-FDG-PET/CT images and clinical data were curated from 697 patients with NSCLC from three institutions and these were analyzed using a small-residual-convolutional-network (SResCNN) to develop a deeply learned score (DLS) to predict the PD-L1 expression status. This developed model was further used to predict DCB, progression-free survival (PFS), and overall survival (OS) in two retrospective and one prospective test cohorts of ICI-treated patients with advanced stage NSCLC.

RESULTS

The PD-L1 DLS significantly discriminated between PD-L1 positive and negative patients (area under receiver operating characteristics curve ≥0.82 in the training, validation, and two external test cohorts). Importantly, the DLS was indistinguishable from IHC-derived PD-L1 status in predicting PFS and OS, suggesting the utility of DLS as a surrogate for IHC. A score generated by combining the DLS with clinical characteristics was able to accurately (C-indexes of 0.70-0.87) predict DCB, PFS, and OS in retrospective training, prospective testing and external validation cohorts.

CONCLUSION

Hence, we propose DLS as a surrogate or substitute for IHC-determined PD-L1 measurement to guide individual pretherapy decisions pending in larger prospective trials.

Immunotherapy in Treating EGFR-Mutant Lung Cancer: Current Challenges and New Strategies

Lung cancer is the leading cause of cancer-related deaths worldwide. Immune checkpoint inhibitors, including monoclonal antibodies against programmed death-1 (PD-1) and programmed death ligand-1 (PD-L1), have dramatically improved the survival and quality of life of a subset of non-small cell lung cancer (NSCLC) patients. Multiple predictive biomarkers have been proposed to select the patients who may benefit from the immune checkpoint inhibitors. EGFR-mutant NSCLC is the most prevalent molecular subtype in Asian lung cancer patients. However, patients with EGFR-mutant NSCLC show poor response to anti-PD-1/PD-L1 treatment. While small-molecule EGFR tyrosine kinase inhibitors (TKIs) are the preferred initial treatment for EGFR-mutant NSCLC, acquired drug resistance is severely limiting the long-term efficacy. However, there is currently no further effective treatment option for TKIs-refractory EGFR-mutant NSCLC patients. The reasons mediating the poor response of EGFR-mutated NSCLC patients to immunotherapy are not clear. Initial investigations revealed that EGFR-mutated NSCLC has lower PD-L1 expression and a low tumor mutational burden, thus leading to weak immunogenicity. Moreover, the use of PD-1/PD-L1 blockade prior to or concurrent with osimertinib has been reported to increase the risk of pulmonary toxicity. Furthermore, emerging evidence shows that PD-1/PD-L1 blockade in NSCLC patients can lead to hyperprogressive disease associated with dismal prognosis. However, it is difficult to predict the treatment toxicity. New biomarkers are urgently needed to predict response and toxicity associated with the use of PD-1/PD-L1 immunotherapy in EGFR-mutated NSCLC. Recently, promising data have emerged to suggest the potentiation of PD-1/PD-L1 blockade therapy by anti-angiogenic agents and a few other novel therapeutic agents. This article reviews the current investigations about the poor response of EGFR-mutated NSCLC to anti-PD-1/PD-L1 therapy, and discusses the new strategies that may be adopted in the future.

Prognostic Impact of PD-L1 Expression in pN1 NSCLC: A Retrospective Single-Center Analysis

Simple Summary

The analysis of prognostic biomarkers (e.g., PD-L1) helps to define treatment for lung cancer patients. To date, these markers have only been examined in metastatic or inoperable situations. We analyzed the PD-L1 expression-levels of tumors from 277 lung cancer patients that underwent curative intent surgery. PD-L1 was identified as a prognostic factor, depending on histologic subtype.

Abstract

The programmed death-ligand 1 (PD-L1) plays a crucial role in immunomodulatory treatment concepts for end-stage non-small cell lung cancer (NSCLC). To date, its prognostic significance in patients with curative surgical treatment but regional nodal metastases, reflecting tumor spread beyond the primary site, is unclear. We evaluated the prognostic impact of PD-L1 expression in a surgical cohort of 277 consecutive patients with pN1 NSCLC on a tissue microarray. Patients with PD-L1 staining (clone SP263) on >1% of tumor cells were defined as PD-L1 positive. Tumor-specific survival (TSS) of the entire cohort was 64% at five years. Low tumor stage (p < 0.0001) and adjuvant therapy (p = 0.036) were identified as independent positive prognostic factors in multivariate analysis for TSS. PD-L1 negative patients had a significantly better survival following adjuvant chemotherapy than PD-L1 positive patients. The benefit of adjuvant therapy diminished in patients with PD-L1 expression in more than 10% of tumor cells. Stratification towards histologic subtype identified PD-L1 as a significant positive predictive factor for TSS after adjuvant therapy in patients with adenocarcinoma, but not squamous cell carcinoma. Routine PD-L1 assessment in curative intent treatment may help to identify patients with a better prognosis. Further research is needed to elucidate the predictive value of PD-L1 in an adjuvant setting.

Serum-derived exosomal PD-L1 expression to predict anti-PD-1 response and in patients with non-small cell lung cancer

PD-L1 expression is the most useful predictive biomarker for immunotherapy efficacy on non-small cell lung cancer (NSCLC), and CD8+ tumor-infiltrating lymphocytes (CD8+ TILs) play an essential role in the clinical activity of immunotherapy. PD-L1 is found on the exosome’s surface, and PD-L1 expressing exosomes can inhibit antitumor immune responses. This study aimed to analyze tumor PD-L1 expression, serum exosomal PD-L1, and CD8+ TILs to investigate anti-PD-1 response and clinicopathological outcomes in NSCLC. One hundred twenty patients with stage I–III NSCLC were enrolled, and serum samples collected during the initial surgery were pooled. The Human CD274/PD-L1 ELISA kit was used to quantify the exosomal PD-L1. Exosomal PD-L1 levels were significantly correlated with tumor PD-L1 levels (p < 0.001) and the number of CD8+ TILs (p = 0.001). Patients with exosomal PD-L1 ≥ 166 pg/mL tended to have a worse RFS than those with < 166 pg/mL in all stage (p = 0.163) and stage I patients (p = 0.116). Seventeen patients exhibited postoperative recurrences and received anti-PD-1 treatment. The disease control rate of patients with exosomal PD-L1 ≥ 166 pg/mL was 100%. The measurement of serum exosomal PD-L1 as a quantitative factor with tumor PD-L1 status may help predict anti-PD-1 response and clinical outcomes in patients with NSCLC.

Prognostic impact of PD-1 and PD-L1 expression in malignant pleural mesothelioma: an international multicenter study

BACKGROUND

Programmed cell death 1/programmed death ligand 1 (PD-1/PD-L1) immune-checkpoint blockade is a promising new therapeutic strategy in cancer. However, expression patterns and prognostic significance of PD-L1 and PD-1 are still controversial in human malignant pleural mesothelioma (MPM).

METHODS

Formalin-fixed paraffin-embedded (FFPE) tumor samples from 203 MPM patients receiving standard treatment without immunotherapy were collected from 5 European centers. PD-L1 and PD-1 expression of tumor cells (TCs) and tumor-infiltrating lymphocytes (TILs) were measured by immunohistochemistry and correlated with clinical parameters and long-term outcome.

RESULTS

High (>10%) PD-L1 TC and PD-1 TILs expressions were found in 18 (8%) and 39 (24%) patients, respectively. PD-L1 was rarely expressed by TILs [≥1%, n=13 (8%); >10%, n=1]. No significant associations were found between the PD-L1 or PD-1 expression of TCs or TILs and clinicopathological parameters such as stage or histological subtype. Notably, patients with high (>10%) TC-specific PD-L1 expression exhibited significantly worse median overall survival (OS) (6.3 vs. 15.1 months of those with low TC PD-L1 expression; HR: 2.51, P<0.001). In multivariate cox regression analysis adjusted for clinical parameters, high TC PD-L1 expression (>10%) proved to be an independent negative prognostic factor for OS (HR: 2.486, P=0.005). There was no significant correlation between PD-L1 or PD-1 expression of TILs and OS.

CONCLUSIONS

In this multicenter cohort study, we demonstrate that high (>10%) PD-L1 expression of TCs independently predicts worse OS in MPM. Further studies are warranted to investigate the value of PD-L1/PD-1 expression as a marker for treatment response in MPM patients receiving immunotherapy.

Mutational signatures in squamous cell carcinoma of the lung

Background

Tumor mutational burden (TMB) has been identified as one of the predictors for the response to anti-programmed cell death-1 (anti-PD-1) antibody therapy and reported to correlate with smoking history in lung adenocarcinoma. However, in squamous cell carcinoma of the lung, the association between TMB and clinicopathological background factors, such as smoking history, has not been reported, including in our previous study. The mutational signature is a tool to identify the mutagens that are contributing to the mutational spectrum of a tumor by investigating the pattern of DNA changes. Here, we analyzed the mutational signature in lung squamous cell carcinoma to identify mutagens affecting the TMB.

Methods

Seven representative mutational signatures including signature 7 (SI7) [ultraviolet (UV)-related], SI4 (smoking), SI6/15 [mismatch repair (MMR)], SI2/13 [apolipoprotein B mRNA editing enzyme, catalytic polypeptide-like (APOBEC)], and SI5 (clock-like) were analyzed in Japanese patients with lung squamous cell carcinoma (n=67) using data generated by next-generation sequencing consisting of a 415-gene panel. The relationships between signatures and clinico-pathological data including TMB and programmed death-ligand 1 (PD-L1) expression were analyzed.

Results

Although the reconstructed mutational counts were small with targeted sequencing (median: 30.1, range: 13.3–98.7), the distributions of signatures were comparable among samples, with 56 cases containing more than four signatures. The smoking-related SI4 was found in 45 cases and was significantly related with pack-year index (PYI) (P=0.026). The reconstructed mutation counts were highly correlated with SI4 (r=0.51, P<0.0001), whereas the correlation was weak with SI6/15 (MMR-related) and SI2/13 (APOBEC-related). There was no mutational signature related with PD-L1 expression. Some patients exhibited unique signatures; the patient with the highest mutational counts had a MMR signature, and another patient with a prominent UV signature had occupational exposure to UV, as he was employed as a neon sign engineer.

Conclusions

Mutational signatures can predict the cause of lung squamous cell carcinoma. Tobacco smoking is the mutagen most related with TMB.

Genotyping Squamous Cell Lung Carcinoma in Colombia (Geno1.1-CLICaP)

Background

Lung cancer is a public health problem, and squamous cell carcinoma (SCC) is the second most prevalent subtype of this neoplasm. Compared to other subtypes, including adenocarcinoma, SCC is less well understood in terms of molecular pathogenesis, limiting therapeutic options among targeted agents approved for other disease subgroups. In this study, we sought to characterize the SCC genomic profile using a validated Next Generation Sequencing (NGS) platform.

Methods

The comprehensive NGS assay (TruSight Tumor 170) was used in order to target the full coding regions of 170 cancer-related genes on SCC samples. PD-L1 expression in tumor cells (TCs) was assessed using clone 22C3 (Dako). Clinical outcomes were correlated with molecular profile, including progression free survival (PFS), overall response rate (ORR), and overall survival (OS).

Results

A total of 26 samples were included, median age was 67 years (r, 33–83) and 53.8% were men. Tobacco consumption was identified in all subjects (mean 34-year package). For first-line treatment 80.8% of patients received cisplatin or carboplatin plus gemcitabine. In terms of molecular profile, we identified a high prevalence of inactivating mutations in TP53 (61.5%), PIK3CA (34.6%), MLL2 (34.6%), KEAP1 (38.4%), and NOTCH1 (26.9%). PD-L1 expression ranged from negative, 1, 2–49, and ≥50% in 23.1, 38.5, 26.9, and 11.5%, respectively. Interestingly, the genetic alterations did not have an effect in PFS, OS or ORR in this study. However, PDL1 expression was higher among those who had mutations in TP53 (p = 0.037) and greater expression of PDL1 was related to PIK3CA alterations (p = 0.05).

Conclusions

The genomic profile of SCC encompasses important genes including TP53, PIK3CA and KEAP1. TP53 mutations could be associated with PDL1 expression, generating hypothesis regarding specific treatment options.

Impact of Programmed Death Ligand 1 Expression in Advanced Non-Small-Cell Lung Cancer Patients, Treated by Chemotherapy (GFPC 06-2015 Study)

Background

Few data have been published on the clinical and histopathological characteristics of advanced non-small–cell lung cancer (NSCLC) patients with high PD-L1 expression versus intermediate or none and the prognostic value of PD-L1 expression for patients treated with chemotherapy is unknown. This study was undertaken to prospectively assess the prognostic value of tumor-cell (TC) and immune-cell (IC) PD-L1 expressions for advanced NSCLC patients.

Methods

It was a prospective, multicenter study on advanced NSCLC patients, with performance status 0/1, scheduled, consecutively, to receive first-line platin-based chemotherapy. PD-L1 expression was determined immunochemically (Dako Autostainer and monoclonal antibody 22C3) and its impact on progression-free survival (PFS) and overall survival (OS) assessed.

Results

Among 198 patients screened in 19 centers, 140 were included median age: 66.5 ± 10 years; 76.4% men; 79.3% Caucasians; 10.7% nonsmokers; 63.6% adenocarcinomas; <1%, 1–50% and ≥50% TC PD-L1–expression rates were 47.1%, 25.7% and 27.2% of patients, respectively; respective null, intermediate and high rates on ICs were 35.7%, 38.6% and 25.7%. Second- and third-line chemotherapies were administered to 58.6% and 26.4% of the patients, respectively. None received immunotherapy. First-, second- and third-line median (95% CI) PFS lasted 4.6 (3.6–5.2), 3.7 (2.3–4.7) and 2.2 (1.5–4.3) months, respectively; median OS was 16.9 (11.4–19.9) months. No significant PFS and OS differences were observed according to TC or IC PD-L1 expression.

Conclusion

According to the results of this prospective, multicenter study, neither TC nor IC PD-L1 expression appears to be prognostic for chemotherapy-managed advanced NSCLC patients.

Clinical outcomes of immune checkpoint blockades and the underlying immune escape mechanisms in squamous and adenocarcinoma NSCLC

Immune checkpoint blockades (ICBs) have changed the standard of care of squamous and adenocarcinoma non‐small cell lung cancer (NSCLC). Whereas detailed researches regarding ICBs in the two major histological subtypes are rare. In order to uncover the clinical efficacy differences between squamous and adenocarcinoma NSCLC and better understand the underlying immune‐regulatory mechanisms, we compared the survival benefits of ICBs between the two subtypes by revealing phase 3 randomized trials and attempted to uncover the immune‐regulatory discrepancy. Generally, compared with nonsquamous NSCLC, squamous NSCLC benefited more from ICBs in Keynote 024, CheckMate 026, CheckMate 227 and CheckMate 017 and similar in OAK, but less in Keynote 010 and PACIFIC. We revealed that the tumor mutation burden (TMB) level, the programmed cell death ligand 1 (PD‐L1) expression, tumor infiltrating lymphocytes (TILs) in the tumor microenvironment (TME), chemokines, and oncogenic driver alterations within the two subtypes may contributed to the clinical outcomes of ICBs. We prospected that the combinations of ICBs with chemotherapy, radiation therapy, and antiangiogenic therapy could be promising strategies to re‐immunize the less immunogenic tumors and further enhance the efficacy of ICBs.

Programmed death ligand 1 protein expression is positively correlated with the solid predominant subtype, high MIB-1 labeling index, and p53 expression and negatively correlated with epidermal growth factor receptor mutations in lung adenocarcinoma

Programmed death ligand 1 (PD-L1) protein expression is a proposed predictive biomarker of immunotherapy; thus, identification of the clinicopathological and molecular characteristics associated with PD-L1 expression is important and necessary. We examined PD-L1 immunohistochemical expression and its relationships with the clinicopathological and molecular characteristics of patients with surgically resected nonsmall cell lung carcinoma. PD-L1 expression differed according to the histological subtype. Among 633 patients with adenocarcinoma, 523 (82.6%) had no PD-L1 expression, 78 (12.3%) low expression, and 32 (5.1%) high expression. PD-L1 expression was more common in men (p < 0.001), in smokers (p = 0.002), and in patients with a more advanced stage (p = 0.002), the solid predominant subtype (p < 0.001), no epidermal growth factor receptor(EGFR) mutations (p < 0.001), a high MIB-1 labeling index (p < 0.001), and positive p53 immunohistochemical expression (p < 0.001). In a multivariate logistic regression analysis, the solid predominant subtype (odds ratio [OR] = 4.92, 95% confidence interval [CI]: 2.72-8.89, p < 0.001), no EGFR mutations (OR = 2.27, 95% CI: 1.35-2.7, p = 0.002), a high MIB-1 labeling index (OR = 2.78, 95% CI: 1.72-4.55, p < 0.001), and p53 positivity (OR = 2.13, 95% CI: 1.34-4.36, p = 0.042) were significantly and independently associated with PD-L1 expression. The combination of the solid predominant subtype with a high MIB-1 labeling index was strongly associated with positive expression of PD-L1. In the 193 patients with squamous cell carcinoma, 92 (47.7%) had no PD-L1 expression, 57 (29.5%) low expression, and 44 (22.8%) high expression. There were no significant correlations between PD-L1 expression and the evaluated clinicopathological or molecular characteristics of these patients. These results, indicating associations of PD-L1 with various clinicopathological or molecular characteristics in adenocarcinoma but not squamous cell carcinoma, may be useful for selecting patients with a good response to immune checkpoint inhibitors.

Biphasic prognostic significance of PD-L1 expression status in patients with early- and locally advanced-stage non-small cell lung cancer

Programmed cell death-ligand 1 (PD-L1) expression on tumor cells is induced by interferon-gamma, suggesting the induction of an anti-tumor immune response. In turn, binding of PD-L1 to programmed cell death 1 (PD-1) triggers an immune checkpoint pathway that contributes to tumor growth. Though it remains to be elucidated, the clinical significance of PD-L1 expression might vary with tumor progression in non-small-cell lung cancer (NSCLC). Immunohistochemical analysis of PD-L1 was done in tumor specimens from patients who underwent radical surgery for stage I-IIIA NSCLC (n = 228). Tumor PD-L1 expression intensity was semi-quantitatively scored and its correlation with various clinicopathological features and postoperative relapse-free survival (RFS) was assessed relative to pathological stage. In stage I, postoperative RFS was significantly prolonged in patients with a high PD-L1 score compared with a low PD-L1 score, exhibiting 5-year relapse-free probabilities of 94.1% and 75.1%, respectively (P = 0.031). A multivariate analysis revealed that a high PD-L1 score was a prognostic factor of longer postoperative RFS (hazard ratio: 0.111, P = 0.033). Conversely, in stages II and IIIA, patients with a high PD-L1 score tended to suffer from postoperative tumor recurrence. In early-stage NSCLC, high tumor PD-L1 expression status represents a biomarker to predict good prognosis after radical surgery and may reflect the induction of an antitumor immune response. However, in locally advanced stage NSCLC, tumor PD-L1 expression status may reflect the execution of an immune checkpoint pathway and predicts the incidence of postoperative tumor recurrence.

CMTM6 is positively correlated with PD-L1 expression and immune cells infiltration in lung squamous carcinoma

BACKGROUND

The aim of this study was to clarify the association between CMTM6 and PD-L1 expression as well as microenvironment in lung squamous carcinoma (LUSC).

MATERIAL AND METHODS

Using Spearman's correlation and Tumor Immune Estimation Resource (TIMER), we analyzed the relationship between CMTM6 and PD-L1 mRNA in LUSC. Immunohistochemistry (IHC) assay was applied to validate the correlation between CMTM6 and PD-L1 protein level in 80 LUSC samples originated from Shandong Provincial Hospital. Then, using The Cancer Genome Atlas (TCGA) database and fisher test, we analyzed the differential mutation genes in high and low CMTM6 expression group. TISIDB was used to explore the distribution of CMTM6 across immune- and molecular-subtypes. TCGA database and Gene Set variation analysis (GSVA) were used to analyze the relationship between CMTM6 and immune genes, immune related pathways.

RESULT

Positive correlation between CMTM6 and PD-L1 in mRNA and protein level was found in LUSC patients. More gene mutations were found in CMTM6 high expression group compared with low expression group. Meanwhile, we also found the correlation between CMTM6 expression and molecular subtypes, immune genes, immune related pathways. Furthermore, our result revealed that B cells memory, T cells memory testing, T cells folicular helper, macrophages M0, macrophages M1 and neutrophils varied significantly between patients with CMTM6 high and low expression group. Finally, we found that CMTM6 expression was positively related to CD8 + T cell, macrophage, neutrophil and dendtritic cell (all, P < 0.05) and negatively related to CD4 + T cell (P = 0.018).

CONCLUSION

CMTM6 is positively associated with PD-L1 expression and correlates with infiltration of immune cells in microenvironment of lung squamous carcinoma.

PD-L1 as a prognostic biomarker in surgically resectable non-small cell lung cancer: a meta-analysis

Background

PD-L1 tumor expression has been associated with poor prognosis in a variety of solid tumors, including lung cancer, and represents a validated target for immune checkpoint inhibition in advanced malignances. It remains unknown, however, if PD-L1 can be used to predict survival in early stage, surgically treated cancers. This meta-analysis compares PD-L1 tumor expression and long term survival after surgical resection in early non-small cell lung cancer (NSCLC).

Methods

PubMed was searched to identify eligible studies that compared survival of surgically resected stage I–III NSCLC patients according to PD-L1 tumor expression. Included studies were grouped according to measurement criteria of PD-L1 expression: 1%, 5%, 50% cutoffs or H-score. Meta-analysis was performed using a linear mixed-effects model to determine overall survival (OS). I² was used as a measure of heterogeneity.

Results

There were 40 eligible studies, including 10,380 patients. Regardless of cut-off used, higher PD-L1 tumor expression was associated with worse OS [hazard ratio (HR)_1%: 1.59, 95% confidence interval (CI), 1.17–2.17; HR_5%: 1.44, 95% CI, 1.03–2.00; HR_50%: 1.52, 95% CI, 1.02–2.25, HR_H-score: 1.34, 95% CI, 1.04–1.73]. Study heterogeneity was low and not statistically significant under all PD-L1 cutoffs.

Conclusions

PD-L1 expression is consistently associated with worse survival, regardless of how it is quantified. In addition to acting as a prognostic biomarker, PD-L1 may also be used in future as a predictive biomarker for patients most likely to benefit from adjuvant immunotherapy.

Uptake of positron emission tomography tracers reflects the tumor immune status in esophageal squamous cell carcinoma

The relationship between the local immune status and cancer metabolism regarding ¹⁸F‐FDG and ¹⁸F‐FAMT uptake in esophageal squamous cell carcinoma (ESCC) remains unknown. The present study examined the correlations between tumor immune status, clinicopathological factors, and positron emission tomography (PET) tracer uptake in ESCC. Forty‐one ESCC patients who underwent ¹⁸F‐FDG PET and ¹⁸F‐FAMT PET before surgery were enrolled in the study. Immunohistochemistry was conducted for programmed death 1 (PD‐1), CD8, Ki‐67, CD34, GLUT1 (¹⁸F‐FDG transporter) and LAT1 (¹⁸F‐FAMT transporter). ESCC specimens with high tumoral PD‐L1 and high CD8‐positive lymphocytes were considered to have “hot tumor immune status.” High PD‐L1 expression (53.7%) was significantly associated with tumor/lymphatic/venous invasion (P = 0.028, 0.032 and 0.018), stage (P = 0.041), CD8‐positive lymphocytes (P < 0.001), GLUT1 (P < 0.001), LAT1 expression (P = 0.006), Ki‐67 labelling index (P = 0.009) and CD34‐positive vessel counts (P < 0.001). SUVmax of ¹⁸F‐FDG was significantly higher in high PD‐L1 cases than in low PD‐L1 cases (P = 0.009). SUVmax of ¹⁸F‐FAMT was significantly higher in high PD‐L1 (P < 0.001), high CD8 (P = 0.012) and hot tumor groups (P = 0.028) than in other groups. High SUVmax of ¹⁸F‐FAMT (≥4.15) was identified as the only predictor of hot tumor immune status. High PET tracer uptake was significantly associated with cancer aggressiveness and hot tumor immune status in ESCC. PET imaging may be an effective tool to predict tumor immune status in ESCC with respect to immune checkpoint inhibitor sensitivity.

A prognostic 11-DNA methylation signature for lung squamous cell carcinoma

Background

Lung squamous cell carcinoma (LUSC), as the second frequent subtype of lung cancer, causes lots of mortalities primarily due to a lack of precise prognostic markers and timely treatment intervention. Previous studies have constructed several risk prognostic models based on DNA methylation sites in multiple tumors, whereas, DNA methylation signature of LUSC remains to be built, and its predictive value need to be evaluated.

Methods

The genome-wide DNA methylation data of LUSC samples was obtained from The Cancer Genome Atlas dataset. Univariate Cox analysis and the least absolute shrinkage and selection operator (LASSO) were implemented to identify DNA methylation sites related to overall survival of LUSC patients. Thus, we performed multivariate Cox regression to establish a DNA methylation signature. The Kaplan-Meier (K-M) survival curves and time-dependent receiver operating characteristic (ROC) curves were plotted to estimate the prognostic power of the signature. Comparison with other known prognostic biomarkers, our DNA methylation signature showed higher predictive specificity and sensitivity. In addition, multivariate Cox regression screened out independent prognostic factors and constructed a nomogram.

Results

Several statistical methods were performed to construct an 11-DNA methylation signature. LUSC patients were divided into low- and high-risk group based on risk score, and high-risk group had a shorter survival time. According to the results of K-M and ROC analyses, the 11-DNA methylation signature showed significant sensitivity and specificity in predicting the LUSC patients’ overall survival. Finally, we integrated some independent prognostic factors (risk score, metastasis stage, and tobacco smoking history) to construct a nomogram, which has excellent prognostic power and may provide guidance for the therapeutic strategies.

Conclusions

We constructed the first risk prognosis model based on DNA methylation site in LUSC, which showed better predictive ability. In addition, a nomogram integrating the DNA methylation signature, metastasis stage, and tobacco smoking history was developed.

Differential Expression and Clinicopathological Significance of HER2, Indoleamine 2,3-Dioxygenase and PD-L1 in Urothelial Carcinoma of the Bladder

Purpose: Evasion of the immune system by cancer cells allows for the progression of tumors. Antitumor immunotherapy has shown remarkable effects in a diverse range of cancers. The aim of this study was to determine the clinicopathological significance of human epidermal growth factor receptor 2 (HER2), indoleamine 2,3-dioxygenase (IDO), and programmed death ligand-1 (PD-L1) expression in urothelial carcinoma of the bladder (UCB). Materials and Methods: We retrospectively studied 97 patients with UCB. We performed an immunohistochemical study to measure the expression levels of HER2, IDO, and PD-L1 in UCB tissue from these 97 patients. Results: In all 97 cases, the PD-L1 expression of tumor-infiltrating immune cells (ICs) was significantly correlated with higher pathologic tumor stage (pT). In pT2–pT4 cases (n = 69), higher levels of HER2 and IDO expression in invasive tumor cells (TCs) were associated with shorter periods of disease-free survival (DFS). Conclusion: These results imply that the expression of PD-L1 in ICs of the UCB microenvironment is associated with cancer invasion and the expression of HER2 or IDO in the invasive cancer cell and suggestive of the potential for cancer recurrence. We suggest that the expression levels of IDO, HER2, and PD-L1 could be useful as targets in the development of combined cancer immunotherapeutic strategies.

Clinical significance of PD-L1-positive cancer-associated fibroblasts in pN0M0 non-small cell lung cancer

OBJECTIVES

Cancer-associated fibroblasts (CAFs) are a dominant cell type in tumor stroma and support the generation of pro-tumorigenic microenvironment. CAFs have frequent opportunities to interact with immune cells infiltrating the tumor stroma, but the process remains to be determined. In this study, we focused on immune checkpoint mechanism. We also examined the induction of programmed cell death-ligand 1 (PD-L1) on CAFs by immune cell, and the clinical significance of PD-L1-expressed CAFs in non-small cell lung cancer (NSCLC).

MATERIALS AND METHODS

CAFs were isolated from human NSCLC tissues, and PD-L1 expression levels in CAFs were analyzed by real-time polymerase chain reaction and flow-cytometry. Following immunohistochemical analysis of PD-L1 in surgically resected pN0M0 NSCLC (n = 125, including 88 invasive adenocarcinomas and 37 squamous cell carcinomas), the correlation of PD-L1-positive CAFs with clinicopathological features was investigated.

RESULTS

PD-L1 mRNA and protein expression on CAFs was upregulated by exogenously supplemented interferon-gamma (IFN-γ) and downregulated through the depletion of IFN-γ. PD-L1 expression on CAFs was upregulated by co-culture with activated lymphocytes releasing IFN-γ. Immunohistochemistry revealed that PD-L1-positive CAFs were observed in 31 cases (24.8%). Postoperative relapse-free survival was significantly prolonged in patients with PD-L1-positive CAFs as compared with those with PD-L1-negative CAFs, with 5-year relapse-free probabilities of 84.5% and 66.3%, respectively (P = 0.031). Multivariate analysis revealed that PD-L1 expression on CAFs was an independent prognostic factor of longer relapse-free survival after surgery (hazard ratio: 3.225, P = 0.027).

CONCLUSION

PD-L1 expression on CAFs is reversibly regulated by environmental stimuli including IFN-γ from activated lymphocytes. In the non-metastatic NSCLC, PD-L1 expression on CAFs suggests the induction of anti-tumor immune responses, contributing to better prognosis after surgery.

The clinicopathological and prognostic significance of PD-L1 expression assessed by immunohistochemistry in lung cancer: a meta-analysis of 50 studies with 11,383 patients

Background

We conducted a meta-analysis to systematically evaluate the relationship between programmed death-ligand 1 (PD-L1) expression and survival in patients with lung cancer.

Methods

The electronic databases PubMed, Embase, Cochrane, and Web of Science were searched up to January 2^nd, 2018, for articles relating to PD-L1 expression detected by immunohistochemistry (IHC) and lung cancer patient prognosis.

Results

Fifty studies including 11,383 patients published between 2011 and 2017 were enrolled in this meta-analysis. The pooled hazard ratios (HRs) and 95% confidence intervals (CIs) suggested that PD-L1 IHC expression was related to poor overall survival (OS) (HR =1.45, 95% CI: 1.24-1.68). In subgroup analysis categorized according to sample type, cut-off value, ethnicity and TNM stage, the pooled results demonstrated inferior survival in the PD-L1 positive group when the PD-L1 expression was detected by resection specimens (P=0.000), 5% was taken as the cutoff value (P=0.000), the patients were in early stage (I-III) (P=0.000), and the geographic setting of the study was in Asia (P=0.000). Besides, patients with high PD-L1 expression had shorter OS in NSCLC (P=0.000), ADC (P=0.000), SCC (P=0.353) and LELC (P=0.810), while no significant difference was observed in SCLC (P=0.000). The pooled odds ratios (ORs) suggested that PD-L1 expression was associated with male (P<0.001), smoker (P<0.001), poor tumor differentiation (P=0.014), large tumor size (P=0.132), positive lymph nodal metastasis (P=0.002), EGFR wild-type status (P<0.001) and KRAS mutations (P=0.393). However, age (P=0.15) and ALK rearrangements (P=0.567) had no bearing on PD-L1 expression.

Conclusions

PD-L1 expression that is associated with several clinicopathological feactures may serve as a poor prognostic biomarker for patients with lung cancer.

Genomic landscape and its correlations with tumor mutational burden, PD-L1 expression, and immune cells infiltration in Chinese lung squamous cell carcinoma

INTRODUCTION

To depict the genomic landscape of Chinese early-stage lung squamous cell carcinoma (LUSC) and investigate its correlation with tumor mutation burden (TMB), PD-L1 expression, and immune infiltrates.

METHODS

Whole-exome sequencing was performed on 189 surgically resected LUSC. TMB was defined as the sum of nonsynonymous single nucleotide and indel variants. CD8⁺ tumor-infiltrating lymphocyte (TIL) density and PD-L1 expression were evaluated by immunohistochemistry. Six immune infiltrates were estimated using an online database.

RESULTS

The median TMB was 9.43 mutations per megabase. Positive PD-L1 expression and CD8⁺ TILs density were identified in 24.3% and 78.8%. PIK3CA amplification was associated with significantly higher TMB (P = 0.036). Frequent genetic alterations had no impact on PD-L1 expression but PIK3CA amplification and KEAP1 mutation were independently associated with significantly lower CD8⁺ TIL density (P < 0.001, P = 0.005, respectively). Low TMB and high CD8⁺ TIL density were independently associated with longer disease-free survival (DFS) while none of them could individually predict the overall survival (OS). Combination of TMB and PD-L1 expression or TMB and CD8⁺ TIL density could stratify total populations into two groups with distinct prognosis. Classifying tumor-immune microenvironment based on PD-L1 expression and CD8⁺ TIL density showed discrepant genomic alterations but similar TMB, clinical features, and OS. Notably, patients with different smoking status had distinct prognostic factors.

CONCLUSION

The combination of TMB, PD-L1 expression, immune infiltrates, and smoking status showed the feasibility to subgroup stratification in Chinese patients with early-stage LUSC, which might be helpful for future design of personalized immunotherapy trials in LUSC.

Positive PD-L1 expression is predictive for patients with advanced EGFR wild-type non-small cell lung cancer treated with gemcitabine and cisplatin

This retrospective study aimed to investigate the association between programmed death ligand-1 (PD-L1) expression and the clinicopathological characteristics of patients with advanced epidermal growth factor receptor (EGFR) wild-type non-small cell lung cancer (NSCLC). The predictive role and cut-off value of PD-L1 expression was subsequently investigated. A total of 172 patients with advanced EGFR wild-type NSCLC were enrolled. All patients received platinum-based doublet chemotherapy (gemcitabine plus cisplatin). PD-L1 expression in lung tissues was assessed using immunohistochemical methods. The χ² test was used to analyze the association between PD-L1 expression and clinicopathological characteristics. Survival time analysis was performed using the Kaplan-Meier method. The two groups, positive PD-L1 expression and negative PD-L1 expression, were compared using the log-rank test. Multivariate analysis using the Cox proportional hazard regression model was conducted to determine prognostic factors for overall survival (OS) and progression-free survival (PFS) times. Positive PD-L1 expression was observed in 48.3% (84/172), 40.7% (70/172), 21.5% (37/172) and 8.1% (14/172) of patients when using cut-off values of 1, 5, 10 and 50%, respectively. The χ² test revealed that elevated pretreatment C-reactive protein (CRP) level and cancer stage IV were significantly associated with positive PD-L1 expression. The OS and PFS of positive PD-L1 (1, 5, 10 and 50% cut-off) expression group were shorter compared with the negative PD-L1 (1, 5, 10 and 50% cut-off) expression group. Multivariate survival analysis revealed that PD-L1 expression ≥50% was significantly associated with decreased OS and PFS [OS time, P=0.001; hazard ratio (HR), 2.768; 95% confidence interval (CI), 1.551–4.940; PFS time, P=0.002; HR, 2.537; 95% CI, 1.423–4.524]. These results indicated that positive PD-L1 (50% cut-off) expression was an independent predictor of poor prognosis for patients with advanced NSCLC treated with gemcitabine plus cisplatin. PD-L1 expression was associated with CRP level and cancer stage. The results obtained in the present study suggest that positive PD-L1 expression serves a prognostic role in advanced NSCLC and that the optimal cut-off value may be 50%.

PD-L1 Expression in Systemic Immune Cell Populations as a Potential Predictive Biomarker of Responses to PD-L1/PD-1 Blockade Therapy in Lung Cancer

PD-L1 tumor expression is a widely used biomarker for patient stratification in PD-L1/PD-1 blockade anticancer therapies, particularly for lung cancer. However, the reliability of this marker is still under debate. Moreover, PD-L1 is widely expressed by many immune cell types, and little is known on the relevance of systemic PD-L1⁺ cells for responses to immune checkpoint blockade. We present two clinical cases of patients with non-small cell lung cancer (NSCLC) and PD-L1-negative tumors treated with atezolizumab that showed either objective responses or progression. These patients showed major differences in the distribution of PD-L1 expression within systemic immune cells. Based on these results, an exploratory study was carried out with 32 cases of NSCLC patients undergoing PD-L1/PD-1 blockade therapies, to compare PD-L1 expression profiles and their relationships with clinical outcomes. Significant differences in the percentage of PD-L1⁺ CD11b⁺ myeloid cell populations were found between objective responders and non-responders. Patients with percentages of PD-L1⁺ CD11b⁺ cells above 30% before the start of immunotherapy showed response rates of 50%, and 70% when combined with memory CD4 T cell profiling. These findings indicate that quantification of systemic PD-L1⁺ myeloid cell subsets could provide a simple biomarker for patient stratification, even if biopsies are scored as PD-L1 null.

Phase III Non-inferiority Study Evaluating Efficacy and Safety of Low Dose Gemcitabine Compared to Standard Dose Gemcitabine With Platinum in Advanced Squamous Lung Cancer

BACKGROUND

Prolonged infusion of low dose gemcitabine (PLDG) in combination with platinum has shown promising activity in terms of improved response rate and progression free survival (PFS); especially in squamous non-small cell lung cancer (NSCLC). Hence, we conducted a phase 3 randomized non-inferiority study with the primary objective of comparing the overall survival (OS) between PLDG and standard dose of gemcitabine with platinum.

METHODOLOGY

Adult subjects (age ≥ 18 years), with stages IIIB-IV, NSCLC (squamous) and ECOG performance status of ≤ 2 were randomized 1:1 into either carboplatin with standard dose gemcitabine (1000 mg/m² intravenous over 30 min, days 1 and 8) (STD-G arm) or carboplatin along with low dose gemcitabine (250 mg/m² intravenous over 6 h, days 1 and 8) (LOW-G arm) for a maximum of 6 cycles. Tumor response was assessed by RECIST criteria version 1.1 every 2 cycles till 6th cycle and thereafter at 2 monthly intervals till progression. The primary endpoint was overall survival. 308 patients were randomized, 155 in STD-G arm and 153 in LOW-G arm, respectively.

RESULTS

The median overall survival in STD-G arm was 6.8 months (95%CI 5.3-8.5) versus 8.4 months (95%CI 7-10.3) in the LOW-G arm (HR-0.890 (90%CI 0.725-1.092). The results with per protocol analysis were in line with these results. There was no statistical difference in progression free survival (HR-0.949; 90%CI 0.867-1.280) and adverse event rate between the 2 arms.

CONCLUSION

This study suggests that PLDG is an alternative to the standard gemcitabine schedule in squamous NSCLC, and either of these can be selected subject to patient convenience.

Role of PD-L1 Expression in Non-Small Cell Lung Cancer and Their Prognostic Significance according to Clinicopathological Factors and Diagnostic Markers

Background: The latest immunotherapy, used in the treatment of non-small cell lung cancer (NSCLC), uses monoclonal antibodies directed against programmed death ligand 1 (PD-L1) to inhibit its interaction with the PD-1 receptor. Elevated levels of PD-L1 expression were observed on NSCLC cells. The association between PD-L1 expression and clinicopathological features is still unclear. Therefore, we examined this relationship and also compare PD-L1 expression levels with Ki-67, p63 and TTF-1. Methods: 866 samples of NSCLCs were used to prepare tissue microarrays (TMAs) on which immunohistochemical (IHC) reactions were performed. Changes in the level of CD274 (PD-L1) gene expression in 62 NSCLC tumors were tested in relation to 14 normal lung tissues by real-time PCR reactions (RT-PCR). Results: PD-L1 expression was observed in 32.6% of NSCLCs. PD-L1 expression was increased in higher malignancy grades (G) (p < 0.0001) and in higher lymph node status (pN) (p = 0.0428). The patients with low PD-L1 expression had longer overall survival compared to the group with high expression (p = 0.0332) in adenocarcinoma (AC) only. Conclusions: PD-L1 expression seems to be associated with increased tumor proliferation and aggressiveness as well as shorter patient survival in NSCLC, predominantly in the AC group.

Radiological Features of Programmed Cell Death-Ligand 2-positive Lung Adenocarcinoma: A Single-institution Retrospective Study

AIM

Programmed cell death-ligand 1 and 2 (PD-L1 and PD-L2) are ligands of the programmed cell death-1 (PD1) receptor. PD1/PD-L1 inhibitors have shown clinical efficacy in non-small cell lung cancer (NSCLC). However, relatively little is known about the expression of PD-L2, or its association with the clinicopathological features of NSCLC. Here, the radiological features of PD-L2-positive lung adenocarcinoma were evaluated.

MATERIALS AND METHODS

PD-L1 and PD-L2 expression were evaluated by immunohistochemical staining of surgically-resected specimens from 393 patients with primary lung adenocarcinoma who underwent preoperative thin-section computed tomography (CT), 222 of whom also underwent ¹⁸F-fluorodeoxyglucose positron-emission tomography/CT (¹⁸F-FDG-PET/CT).

RESULTS

Among the 393 specimens, 132 (33.6%) and 266 (67.7%) were positive for PD-L1 and PD-L2 expression, respectively. Multivariate analysis showed that the absence of surrounding ground glass opacity and the presence of air bronchogram were significantly associated with PD-L2 expression; however, there was no significant association between PD-L2 expression and the consolidation/tumor ratio. In 222 ¹⁸F-FDG-PET/CT, the maximum standardized uptake value was significantly higher in patients with PD-L2-positive compared to those with PD-L2-negative tumors.

CONCLUSION

PD-L2-positive lung adenocarcinomas are less radiologically malignant and invasive than their PD-L1-positive counterparts.

Programmed death ligand 1 expression in early stage, resectable non-small cell lung cancer

INTRODUCTION

For several years non-small cell lung cancer (NSCLC) has been considered non-immunogenic. Recent advances in antitumor immunity brought to the discovery of checkpoints that modulate immune response against cancer. One of them is programmed death receptor 1 (PD-1) and its ligand (PD-L1). Although PD-L1 expression seems predictive of response to anti-PD-1/PD-L1 agents, its prognostic value is unclear. In this study we investigated the prognostic value of PD-L1 expression and its correlation with clinical-pathological characteristics in a cohort of surgically resected NSCLC.

MATERIAL AND METHODS

PD-L1 expression was evaluated in 289 surgically resected NSCLC samples by immunohistochemistry. Our cohort included patients not exposed to adjuvant chemotherapy. PD-L1 status was defined as: 1) PD-L1 high (tumor proportion score, TPS≥50%), PD-L1 low (TPS 1-49%), PD-L1 negative (TPS<1%); 2) PD-L1 positive (TPS≥50%) and negative (TPS<50%); 3) as a continuous variable.

RESULTS

Patients were mostly males (79%), former or current smokers (81%), with a median age of 67 years, non-squamous histology (67.5%) and high-grade tumors (55%). PD-L1 tumors were 18.7%. There was no significant association with sex, age, smoking status and histology. A strong correlation between high PD-L1 expression and tumor grade was detected. The difference in median OS in the different groups of patients was not statistically significant.

CONCLUSION

PD-L1 is not prognostic in surgically resected NSCLC. The association with tumor differentiation suggests that grading could represent an easy-to-assess tool for selecting subjects potentially sensitive to immunotherapy warranting further investigations.

Clinical significance of ≥ 50% PD-L1 expression with the SP263 monoclonal antibody in non-small cell lung cancer patients

BACKGROUND

PD-L1 expression in tumor cells has been associated with the efficacy of immune checkpoint inhibitors in non-small cell lung cancer (NSCLC). The aim of this study was to explore correlations between smoking, genetic profiles, patient outcomes, and PD-L1 expression in NSCLC.

METHODS

PD-L1 expression was evaluated in 241 surgically resected specimens by immunostaining and 50% was set as the cutoff value.

RESULTS

Of the 241 tumors analyzed, a PD-L1 tumor proportion score (TPS) of ≥ 50% was detected in 35 cases (14.5%) and a TPS of < 50% in 206 cases (85.5%). A PD-L1 TPS ≥ 50% was significantly associated with smoking and EGFR wild-type status (P < 0.001 and P = 0.039, respectively). Detailed assessment of smoking variables showed that total smoking duration was a predictor of a PD-L1 TPS ≥ 50% (P = 0.001). Univariate and multivariate survival analyses revealed that patients with a PD-L1 TPS ≥ 50% had poorer disease-free and overall survival than those with a PD-L1 TPS < 50% (P = 0.001 and P < 0.001, respectively).

CONCLUSION

The incidence of a PD-L1 TPS ≥ 50% was significantly higher in smoking and EGFR wild-type NSCLC patients, particularly in long-term smokers. A PD-L1 TPS of ≥ 50% was an independent adverse prognostic factor for survival in patients with NSCLC.

Co-expression of IDO1 and PD-L1 in lung squamous cell carcinoma: Potential targets of novel combination therapy

OBJECTIVES

Combination therapy with an inhibitor of indoleamine 2, 3-dioxygenase 1 (IDO1) and an agent targeting programmed cell death-1 (PD-1)/programmed cell death-ligand 1 (PD-L1) is expected to be a novel and effective treatment option for various solid tumors including non-small cell lung cancer (NSCLC). Therefore, it is important to elucidate the clinical and pathological features of tumors with IDO1/PD-L1 co-expression and the association between IDO1/PD-L1 co-expression and efficacy of combination therapy in NSCLC patients. In this study, we examined the prognostic impact of IDO1/PD-L1 co-expression and its relationship with tumor-infiltrating lymphocytes (TILs) in primary lung squamous cell carcinoma (SCC).

MATERIALS AND METHODS

The expression levels of IDO1, PD-L1, Ki-67, cluster of differentiation 3 (CD3), CD4, and CD8 in 202 patients with surgically resected primary lung SCC were evaluated by immunohistochemistry.

RESULTS

Among 202 patients, 176 (87.1%) were positive for IDO1 expression, 106 (52.5%) were positive for PD-L1 expression, and 99 (49.0%) showed co-expression of IDO1/PD-L1 proteins. Fisher's exact test showed a significant association between IDO1 and PD-L1 tumor proportion scores (P =  0.0011). Kaplan-Meier curve showed that PD-L1 alone and co-expression of IDO1 and PD-L1 were significantly associated with shorter overall survival, but IDO1 alone was not (log rank test: P =  0.0122, P =  0.0303 and P =  0.5168, respectively). The Ki-67 labeling index was significantly higher in patients with co-expression of IDO1 and PD-L1 than in patients without co-expression (Student's t-test: P =  0.0005). Moreover, IDO1/PD-L1 co-expression was significantly associated with high CD3, CD4, and CD8 expression (Fisher's exact test: P =  0.0033, P =  0.0003, and P <  0.0001, respectively).

CONCLUSIONS

IDO1 expression correlated to PD-L1 expression, and co-expression of IDO1 and PD-L1 may be important targets for immunotherapy in lung SCC.

[Predictive Markers for Treating Efficacy of PD-1/PD-L1 Inhibitors in Patients with Lung Cancer: A Review of the 18th World Conference on Lung Cancer]

Programmed cell death-1 (PD-1)/programmed cell death-ligand 1 (PD-L1) checkpoint blockades have dramatically changed the treatment of non-small cell lung cancer (NSCLC). But we still have no definite biomarkers that may predict the efficacy of treatment by PD-1/PD-L1 inhibitors. In the 18th World Conference on Lung Cancer, the biomarkers that may predict the efficacy of treatment by PD-1/PD-L1 inhibitors in patients with lung cancer has been a popular topic, and it has huge potential in the future. In order to enable more patients to get more benefits from treatment, researchers are looking forward to finding the optimum biomarkers. By organizing and summarizing the information about the biomarkers predicting PD-1/PD-L1 in patients with lung cancer, this review mainly focused on the following six aspects to introduce: expression of PD-L1; tumor mutational burden and the ability of mutation repair, malignant tumor driver mutation, biomarker of immunological effect, blood cell account, comprehensive analysis model. We are hoping to help doctors to find the best biomarker, then much more lung cancer patients could obtain antitumor effects in PD-1/PD-L1 inhibitors treatment.
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Differences in PD-L1 expression on tumor and immune cells between lung metastases and corresponding primary tumors

BACKGROUND

It has been reported that the tumor microenvironment, including tumor-associated immune cells (ICs) and programmed cell death-ligand 1 (PD-L1) expression, differs between primary and metastatic tumors. This study aimed to elucidate the differences in PD-L1 expression on tumor cells (TCs) and ICs between lung metastases and corresponding primary tumors.

METHODS

We analyzed paired lesions from 44 patients diagnosed with lung metastases between 2005 and 2017 at Kyushu University. The percentages of PD-L1-positive TCs and ICs in lung metastases and the primary tumor were classified into five categories (0: <1%; 1: 1%-4%; 2: 5%-9%; 3: 10%-49%; and 4: ≥50%). Lesions in which ≥1% of the TCs and ICs were PD-L1-positive were considered positive.

RESULTS

The primary cancers included rectal (n = 19), colon (n = 10), liver (n = 10), bile duct (n = 2), stomach (n = 1), gall bladder (n = 1) and breast (n = 1). Discrepancies in PD-L1 expression on TCs and ICs between lung metastases and primary lesions were observed in 5 (11.4%, κ = 0.23) and 9 (20.5%, κ = 0.11) of the 44 cases, respectively. PD-L1 expression on ICs was higher in lung metastases than paired primary tumors (p = 0.026), although the percentage of PD-L1-positive TCs was not significantly different between lung metastases and primary tumors (p = 0.767).

CONCLUSIONS

There were significant differences in PD-L1 expression on TCs and ICs between lung metastases and primary tumors. Clinicians should be aware of these differences in the tumor microenvironment when treating patients with immunotherapy.

Genetic, transcriptional and post-translational regulation of the programmed death protein ligand 1 in cancer: biology and clinical correlations

The programmed death protein 1 (PD-1) and its ligand (PD-L1) represent a well-characterized immune checkpoint in cancer, effectively targeted by monoclonal antibodies that are approved for routine clinical use. The regulation of PD-L1 expression is complex, varies between different tumor types and occurs at the genetic, transcriptional and post-transcriptional levels. Copy number alterations of PD-L1 locus have been reported with varying frequency in several tumor types. At the transcriptional level, a number of transcriptional factors seem to regulate PD-L1 expression including HIF-1, STAT3, NF-κΒ, and AP-1. Activation of common oncogenic pathways such as JAK/STAT, RAS/ERK, or PI3K/AKT/MTOR, as well as treatment with cytotoxic agents have also been shown to affect tumoral PD-L1 expression. Correlative studies of clinical trials with PD-1/PD-L1 inhibitors have so far shown markedly discordant results regarding the value of PD-L1 expression as a marker of response to treatment. As the indications for immune checkpoint inhibition broaden, understanding the regulation of PD-L1 in cancer will be of utmost importance for defining its role as predictive marker but also for optimizing strategies for cancer immunotherapy. Here, we review the current knowledge of PD-L1 regulation, and its use as biomarker and as therapeutic target in cancer.

Lung Cancers: Molecular Characterization, Clonal Heterogeneity and Evolution, and Cancer Stem Cells

Lung cancer causes the largest number of cancer-related deaths in the world. Most (85%) of lung cancers are classified as non-small-cell lung cancer (NSCLC) and small-cell lung cancer (15%) (SCLC). The 5-year survival rate for NSCLC patients remains very low (about 16% at 5 years). The two predominant NSCLC histological phenotypes are adenocarcinoma (ADC) and squamous cell carcinoma (LSQCC). ADCs display several recurrent genetic alterations, including: KRAS, BRAF and EGFR mutations; recurrent mutations and amplifications of several oncogenes, including ERBB2, MET, FGFR1 and FGFR2; fusion oncogenes involving ALK, ROS1, Neuregulin1 (NRG1) and RET. In LSQCC recurrent mutations of TP53, FGFR1, FGFR2, FGFR3, DDR2 and genes of the PI3K pathway have been detected, quantitative gene abnormalities of PTEN and CDKN2A. Developments in the characterization of lung cancer molecular abnormalities provided a strong rationale for new therapeutic options and for understanding the mechanisms of drug resistance. However, the complexity of lung cancer genomes is particularly high, as shown by deep-sequencing studies supporting the heterogeneity of lung tumors at cellular level, with sub-clones exhibiting different combinations of mutations. Molecular studies performed on lung tumors during treatment have shown the phenomenon of clonal evolution, thus supporting the occurrence of a temporal tumor heterogeneity.

[Immunotherapy - The New Era of Oncology]

In the field of immunotherapy, essential progress was achieved over the past years partially demonstrating long lasting therapeutic responses in different tumor entities. A better understanding of the interactions between the tumor and the immune system as well as the integration of immunotherapeutic approaches into clinical routine were the foundations for this development. The different approaches intervene on multiple levels of the immune response and directly or indirectly mount the patient‘s own immune defense against tumor cells. Immunotherapeutic approaches are represented by cytokine therapies, vaccinations, the use of oncolytic viruses and monoclonal antibody therapies as well as adoptive cell transfer strategies.