EML4-ALK enhances programmed cell death-ligand 1 expression in pulmonary adenocarcinoma via hypoxia-inducible factor (HIF)-1α and STAT3

Programmed cell death (PD)-1/PD-1 ligand-1 (PD-L1)-targeted therapy has emerged as a promising therapeutic strategy for lung cancer. However, whether EML4-ALK regulates PD-L1 expression in lung cancer remains unknown. A total of 532 pulmonary adenocarcinomas (pADCs), including 58 ALK-translocated tumors, were immunohistochemically evaluated for PD-L1 and PD-1. H23 (EGFR^Wild-typeEML4-ALK^-PD-L1^Low) and H2228 (EGFR^Wild-typeEML4-ALK⁺PD-L1^High) cells were transfected with EML4-ALK or ALK short interfering RNAs and used to investigate the alterations in PD-L1 expression. PD-L1 expression was detected in 81% of ALK-translocated pADCs; this value was significantly higher than those of pADCs with EGFR mutation, KRAS mutation or lacking ALK, EGFR or KRAS mutation (p <0.005 for all). Moreover, ALK-translocated pADC with PD-L1 expression showed significantly higher numbers of tumor-infiltrating PD-1⁺ cells. ALK knockdown or inhibition (crizotinib treatment) in H2228 cells downregulated PD-L1 expression. Transfection of H23 cells with EML4-ALK enhanced PD-L1 expression, which was compromised by crizotinib treatment. This ALK-dependent upregulation of PD-L1 expression was mediated by STAT3 and hypoxia-inducible factor (HIF)-1α under normoxia and hypoxia. Furthermore, EML4-ALK enhanced HIF-1α expression through increasing transcription and decreasing ubiquitination of HIF-1α. In ALK-translocated pADC tissues, significant positive correlations between PD-L1 and nuclear HIF-1α (p < 0.05) or pSTAT3 expression levels (p<0.005) were observed. Among patients with ALK-translocated pADC, strong PD-L1 expression was significantly associated with shorter progression-free (p = 0.001) and overall survival (p = 0.002) after crizotinib treatment. Collectively, our findings demonstrate that ALK-derived pADCs increase PD-L1 expression via HIF-1α and/or STAT3, thus providing a rationale for PD-1/PD-L1 pathway-targeted therapy in ALK-translocated lung cancer.

PD-1/PD-L1-dependent immune response in colorectal cancer

Colorectal cancer (CRC) is still considered as the third most frequent cancer in the world. Microsatellite instability (MSI), inflammation, and microRNAs have been demonstrated as the main contributing factors in CRC. Subtype 1 CRC is defined by NK cells infiltration, induction of Th1 lymphocyte and cytotoxic T cell responses as well as upregulation of immune checkpoint proteins including programmed cell death-1 (PD-1). Based on the diverse features of CRC, such as the stage and localization of the tumor, several treatment approaches are available. However, the efficiency of these treatments may be decreased due to the development of diverse resistance mechanisms. It has been proven that monoclonal antibodies (mAbs) can increase the effectiveness of CRC treatments. Nowadays, several mAbs including nivolumab and pembrolizumab have been approved for the treatment of CRC. Immune checkpoint receptors including PD-1 can be inhibited by these antibodies. Combination therapy gives an opportunity for advanced treatment for CRC patients. In this review, an update has been provided on the molecular mechanisms involved in MSI colorectal cancer immune microenvironment by focusing on PD-ligand 1 (PD-L1) and treatment of patients with advanced immunotherapy, which were examined in the different clinical trial phases. Considering induced expression of PD-L1 by conventional chemotherapeutics, we have summarized the role of PD-L1 in CRC, the chemotherapy effects on the PD-1/PD-L1 axis and novel combined approaches to enhance immunotherapy of CRC by focusing on PD-L1.

Combining BRAF inhibitor and anti PD-L1 antibody dramatically improves tumor regression and anti tumor immunity in an immunocompetent murine model of anaplastic thyroid cancer

The interaction of programmed cell death-1 and its ligand is widely studied in cancer. Monoclonal antibodies blocking these molecules have had great success but little is known about them in thyroid cancer. We investigated the role of PD-L1 in thyroid cancer with respect to BRAF mutation and MAP kinase pathway activity and the effect of anti PD-L1 antibody therapy on tumor regression and intra-tumoral immune response alone or in combination with BRAF inhibitor (BRAFi). BRAFV600E cells showed significantly higher baseline expression of PD-L1 at mRNA and protein levels compared to BRAFWT cells. MEK inhibitor treatment resulted in a decrease of PD-L1 expression across all cell lines. BRAFi treatment decreased PD-L1 expression in BRAFV600E cells, but paradoxically increased its expression in BRAFWT cells. BRAFV600E mutated patients samples had a higher level of PD-L1 mRNA compared to BRAFWT (p=0.015). Immunocompetent mice (B6129SF1/J) implanted with syngeneic 3747 BRAFV600E/WT P53-/- murine tumor cells were randomized to control, PLX4720, anti PD-L1 antibody and their combination. In this model of aggressive thyroid cancer, control tumor volume reached 782.3±174.6mm3 at two weeks. The combination dramatically reduced tumor volume to 147.3±60.8, compared to PLX4720 (439.3±188.4 mm3, P=0.023) or PD-L1 antibody (716.7±62.1, P<0.001) alone. Immunohistochemistry analysis revealed intense CD8+ CTL infiltration and cytotoxicity and favorable CD8+:Treg ratio compared to each individual treatment. Our results show anti PD-L1 treatment potentiates the effect of BRAFi on tumor regression and intensifies anti tumor immune response in an immunocompetent model of ATC. Clinical trials of this therapeutic combination may be of benefit in patients with ATC.

Immune Checkpoint Inhibitor-Associated Cardiotoxicity: Current Understanding on Its Mechanism, Diagnosis and Management

Immune checkpoint inhibitors (ICIs) that target cytotoxic T lymphocyte antigen 4, programmed cell death-1, and PD-ligand 1 have revolutionized cancer treatment, achieving unprecedented efficacy in multiple malignancies. ICIs are increasingly being used in early cancer settings and in combination with various other types of therapies, including targeted therapy, radiotherapy, and chemotherapy. However, despite the excellent therapeutic effect of ICIs, these medications typically result in a broad spectrum of toxicity reactions, termed immune-related adverse events (irAEs). Of all irAEs, cardiotoxicity, uncommon but with high mortality, has not been well recognized. Herein, based on previous published reports and current evidence, we summarize the incidence, diagnosis, clinical manifestations, underlying mechanisms, treatments, and outcomes of ICI-associated cardiotoxicity and discuss possible management strategies. A better understanding of these characteristics is critical to managing patients with ICI-associated cardiotoxicity.

Prognostic Role and Clinical Significance of Tumor-Infiltrating Lymphocyte (TIL) and Programmed Death Ligand 1 (PD-L1) Expression in Triple-Negative Breast Cancer (TNBC): A Systematic Review and Meta-Analysis Study

This meta-analysis aimed to evaluate the prognostic value of tumor-infiltrating lymphocytes (TILs) and programmed death-ligand 1 (PD-L1), their associations with the clinicopathological characteristics, and the association between their levels in patients with triple-negative breast cancer (TNBC). PubMed, EMBASE, Scopus, ProQuest, Web of Science, and Cochrane Library databases were searched to obtain the relevant papers. Seven studies with 1152 patients were included in this study. Like the level of TILs, there were no significant associations between PD-L1 expression and tumor size, tumor stage, lymph node metastasis, histological grade, and Ki67 (All p-values ≥ 0.05). Furthermore, there was no significant association between PD-L1 expression with overall survival (OS) and disease-free survival (DFS). In assessment of TILs and survival relationship, the results showed that a high level of TILs was associated with long-term OS (hazard ratios (HR) = 0.48, 95% CI: 0.30 to 0.77, p-value < 0.001) and DFS (HR = 0.53, 95% CI: 0.35 to 0.78, p-value < 0.001). The results displayed that tumoral PD-L1 expression was strongly associated with high levels of TILs in TNBC patients (OR = 8.34, 95% CI: 2.68 to 25.95, p-value < 0.001). In conclusion, the study has shown the prognostic value of TILs and a strong association between tumoral PD-L1 overexpression with TILs in TNBC patients.

Immune Checkpoint Inhibitors and Cardiac Toxicity in Patients Treated for Non-Small Lung Cancer: A Review

Lung cancer is a major cause of cancer-related mortality worldwide, both in men and women. The vast majority of patients are diagnosed with non-small-cell lung cancer (NSCLC, 80-85% of lung cancer cases). Therapeutics named immune checkpoint inhibitors (ICIs) have revolutionized cancer treatment in the last decade. They are monoclonal antibodies, and those directed against PD-1 (programmed cell death protein 1) or PD-L1 (programmed cell death-ligand 1) have been used in the treatment of lung cancer and significantly improved the prognosis of NSCLC patients. However, during treatment with ICIs, immune-related adverse events (irAEs) can occur in any organ and any tissue. At the same time, although cardiac irAEs are relatively rare compared to irAEs in other organs, they have a high mortality rate. The two most common clinical manifestations of immunotherapy-related cardiotoxicity are myocarditis and pericarditis. Various types of arrhythmias have been reported in patients treated with ICIs, including the occurrence of life-threatening complete atrioventricular block or ventricular tachyarrhythmias. Here, we aim to summarize the incidence, clinical manifestations, underlying mechanisms, diagnosis, and treatment strategies for ICI-associated cardiotoxicity as these issues become very important in view of the increasing use of ICI in the treatment of lung cancer.

PD-L1 immunohistochemical assays for assessment of therapeutic strategies involving immune checkpoint inhibitors in non-small cell lung cancer: a comparative study

Although immune checkpoints inhibitors have exhibited promising activity in clinical trials in non-small cell lung cancer (NSCLC) patients, the current programmed cell death-ligand 1 (PD-L1) assays are inconsistent in terms of the staining analysis and scoring system used. To verify the interchangeability of the available PD-L1 assays, we performed immunohistochemistry using three antibody clones used in clinical trials (22C3, SP263, and SP142) and the E1L3N clone as a laboratory developed test for 97 resected NSCLC specimens. Matched tissue microarray specimens were also stained. Staining with 22C3 yielded a greater proportion of stained tumor cells, whereas SP142 staining consistently labelled fewer tumor cells. However, when various cut-off criteria were applied, the positivity rates for PD-L1 were similar, with high concordance, under assay-specific cut-offs. Moreover, seven cases of discordant PD-L1 expression between the resected specimen and matched tissue microarray specimens were observed. In conclusion, despite of inter-assay variability of the PD-L1 status in NSCLC, the positivity rate appears to be similar under assay-specific criteria. Hence, an appropriate clinically defined algorithm or cut-off should be separately applied for each assay. Moreover, multiple biopsy specimens from different tumor areas should be obtained to reduce false results due to intratumoral heterogeneity in PD-L1 expression.

Prognostic value of programmed cell death-ligand 1 expression in patients with non-small-cell lung cancer: evidence from an updated meta-analysis

Background

The association between the expression of programmed cell death-ligand 1 (PD-L1) and survival in patients with non-small-cell lung cancer (NSCLC) is controversial. Thus, we conducted a meta-analysis of all available studies to evaluate the prognostic role of PD-L1 expression in NSCLC.

Materials and methods

PubMed, Embase, and Chinese (China National Knowledge Infrastructure and Wanfang) databases were searched to identify all eligible studies evaluating PD-L1 expression and the survival of NSCLC patients. Hazard ratios (HRs) and 95% confidence interval (CI) used to assess overall survival were extracted and pooled. Subgroup, sensitivity, and publication-bias analyses were also performed.

Results

Eleven articles reporting 12 studies that included a total of 1,653 patients met the inclusion criteria and were included in the meta-analysis. Higher PD-L1 expression did not correlate with prognosis in terms of overall survival in patients with NSCLC (HR =1.21, 95% CI: 0.85–1.71, P=0.29). However, a subgroup analysis showed a significant association between PD-L1 expression and poor prognosis in Chinese patients with NSCLC (HR =1.55, 95% CI: 1.04–2.29, P=0.03). The sensitivity analysis showed that the pooled results were not affected by the removal of any single study. There was also no significant publication bias.

Conclusion

Our meta-analysis indicated no statistically significant difference between PD-L1 expression and prognosis for patients with NSCLC. Additional, high-quality studies with larger sample sizes are needed to determine the prognostic value of PD-L1 expression in NSCLC.

Comparability of PD-L1 immunohistochemistry assays for non-small-cell lung cancer: a systematic review

Programmed cell death ligand 1 (PD‐L1) immunohistochemistry is used to determine which patients with advanced non‐small‐cell lung cancer (NSCLC) respond best to treatment with PD‐L1 inhibitors. For each inhibitor, a unique immunohistochemical assay was developed. This systematic review gives an up‐to‐date insight into the comparability of standardised immunohistochemical assays and laboratory‐developed tests (LDTs), focusing specifically on tumour cell (TC) staining and scoring. A systematic search was performed identifying publications that assessed interassay, interobserver and/or interlaboratory concordance of PD‐L1 assays and LDTs in tissue of NSCLC patients. Of 4294 publications identified through the systematic search, 27 fulfilled the inclusion criteria and were of sufficient methodological quality. Studies assessing interassay concordance found high agreement between assays 22C3, 28‐8 and SP263 and properly validated LDTs, and lower concordance for comparisons involving SP142. A decrease in concordance, however, is seen with use of cut‐offs, which hampers interchangeability of PD‐L1 immunohistochemistry assays and LDTs. Studies assessing interobserver concordance found high agreement for all assays and LDTs, but lower agreement with use of a 1% cut‐off. This may be problematic in clinical practice, as discordance between pathologists at this cut‐off may result in some patients being denied valuable treatment options. Finally, five studies assessed interlaboratory concordance and found moderate to high agreement levels for various assays and LDTs. However, to assess the actual existence of interlaboratory variation in PD‐L1 testing and PD‐L1 positivity in clinical practice, studies using real‐world clinical pathology data are needed.

Positive expression of programmed death ligand-1 correlates with superior outcomes and might be a therapeutic target in primary pulmonary lymphoepithelioma-like carcinoma

Background

Primary pulmonary lymphoepithelioma-like carcinoma (LELC) is a rare subtype of non-small cell lung cancer (NSCLC), and no effective treatments have been defined for advanced disease. Programmed cell death-ligand 1 (PD-L1) is expressed in a group of cancers that may be suitable targets for specific immunotherapy.

Methods

This study investigated the expression and clinical value of PD-L1 in pulmonary LELC. Seventy-nine patients with pulmonary LELC were investigated. Paraffin-embedded tumor sections were stained with PD-L1 antibody. Correlations of PD-L1 expression with clinicopathologic parameters and outcomes were analyzed.

Results

Fifty patients (63.3%) were PD-L1 positive. The 3-year and 5-year progression-free survival (PFS) rate was 76.0% and 68.0%, respectively, and the 3-year and 5-year overall survival (OS) rate was 88.0% and 79.0%, respectively. Kaplan–Meier analysis revealed that patients with positive PD-L1 expression had longer PFS and OS than those with negative PD-L1 expression (P=0.019 and P=0.042, respectively). In a multivariate Cox regression model including age, tumor size, stage, and PD-L1 expression status, the latter three factors were found to be independent predictors of PFS (P=0.023, P=0.000, and P=0.009, respectively), but only stage was found to be an independent factor for OS (P=0.007), and PD-L1 expression status showed a trend to be independently correlated with OS (P=0.080).

Conclusion

Our results showed that a large proportion of patients with pulmonary LELC had positive expression of PD-L1, supporting the potential use of anti-PD-1/PD-L1-targeted therapies in this distinct type of NSCLC.

Nivolumab plus ipilimumab versus pembrolizumab as chemotherapy-free, first-line treatment for PD-L1-positive non-small cell lung cancer

BACKGROUND

Nivolumab plus ipilimumab (N-I) or pembrolizumab (PEM) is associated with survival improvement as chemotherapy-free, first-line treatment for patients with advanced non-small cell lung carcinoma (NSCLC) and positive programmed cell death ligand 1 (PD-L1). However, no direct comparison data exist between these two regimens to inform clinical decisions. Therefore, we performed indirect comparison for N-I versus PEM using frequentist methods.

RESULTS

Three randomized trials (KEYNOTE-024, KEYNOTE-042, and CheckMate 227) involving 2372 patients were included. For patients with tumor PD-L1 level of ≥1%, pooled meta-analyses showed that both N-I and PEM improved overall survival (OS) relative to chemotherapy (N-I: hazard ratio [HR] 0.82, 95% CI 0.69-0.97; PEM: HR 0.81, 95% CI 0.71-0.93); whereas only N-I significantly improved progression-free survival (PFS) (N-I: HR 0.79, 95% CI 0.65-0.96; PEM: HR 1.07, 95% CI 0.94-1.21). Neither N-I nor PEM was associated with improved objective response rate (ORR) compared with chemotherapy (N-I: relative risk [RR] 1.20, 95% CI 0.98-1.46; PEM: RR 1.03, 95% CI 0.86-1.23). Indirect comparisons showed that N-I was associated with longer PFS than PEM (HR 0.77, 95% CI 0.62-0.95). However, N-I was not superior to PEM in terms of OS (HR 0.98, 95% CI 0.77-1.24) and ORR (RR 1.17, 95% CI 0.89-1.52). N-I showed a less favorable toxicity profile relative to PEM (all grade adverse events: RR 1.28, 95% CI 1.17-1.40).

CONCLUSIONS

N-I and PEM provide comparable OS benefit for PD-L1-positive NSCLC. N-I further improves PFS relative to PEM but at meaningful cost of toxicities.

Treatment outcomes of patients with adenocarcinoma of the uterine cervix after definitive radiotherapy and the prognostic impact of tumor-infiltrating CD8+ lymphocytes in pre-treatment biopsy specimens: a multi-institutional retrospective study

The current study aimed to evaluate the outcomes of patients with adenocarcinoma (AC) of the uterine cervix after definitive radiotherapy (RT) and to evaluate prognostic factors, including immunity-related molecules. A total of 71 patients with AC of the uterine cervix from multiple Japanese institutions were retrospectively analysed. Histological subtypes were diagnosed according to the 2014 World Health Organization classification. All patients underwent definitive RT comprising external beam RT and intracavitary brachytherapy with or without concurrent chemotherapy. Immunohistochemical studies were performed to detect the expression of programmed cell death-ligand 1(PD-L1) and CD8. The 5-year locoregional control (LC), overall survival (OS) and progression-free survival (PFS) rates for all patients were 61.8, 49.7 and 36.1%, respectively. The LC, OS and PFS rates were not significantly different among the histological subtypes. Membranous PD-L1 expression was not significantly associated with prognosis. Patients with CD8-positive tumor-infiltrating lymphocytes (CD8+TILs) in the tumor nests had significantly better OS than patients without CD8+TILs in the tumor nests (5-year OS: 53.8 vs 23.8%, P = 0.038). As expected, the International Federation of Gynecology and Obstetrics (FIGO) stage (2008) III-IVA and maximum tumor diameter > 40 mm were significantly associated with worse prognosis. In summary, the presence of CD8+TILs in the tumor nests has the potential to be an independent favorable prognostic factor for patients with AC of the uterine cervix after definitive RT.

Programmed cell death 1 expression is associated with inferior survival in patients with primary central nervous system lymphoma

Programmed cell death 1 (PD-1) and its ligands PD-L1/PD-L2 have been shown to mediate immune evasion in various cancers, but their prognostic implications in patients with primary central nervous system lymphoma (PCNSL) are poorly understood. Therefore, we analyzed 76 PCNSL patients at initial diagnosis who were treated homogenously with high-dose methotrexate-based chemotherapy, and evaluated the prognostic roles of high immunohistochemical PD-1, PD-L1, and PD-L2 expression. The cut-off values for high PD-1 (≥ 70 cells/high power field [HPF]), PD-L1 (≥ 100 cells/HPF), and PD-L2 (≥ 100 cells/HPF) were determined by the area under the receiver operating characteristic curve. Expression of PD-1, PD-L1, and PD-L2 was high in 7.9%, 13.2%, and 42.1% patients, respectively. High PD-1, (P = 0.007) and Memorial Sloan Kettering Cancer Center (MSKCC) prognostic scoring (P = 0.019) were independently associated with inferior overall survival on multivariate analysis. High PD-1 also remained an independent prognostic factor for inferior progression-free survival (P = 0.028), as did MSKCC prognostic scoring (P = 0.041) on multivariate analysis. However, there were no differences in survival according to the expression levels of PD-L1/PD-L2 in PCNSL tumor microenvironment. Our results suggest that PD-1 may be considered a biomarker and potential therapeutic target in PCNSL.

Synergistic effect of ibrutinib and CD19 CAR-T cells on Raji cells in vivo and in vitro

Ibrutinib might improve the efficacy of anti‐CD19 chimeric antigen receptor (CD19 CAR) T‐cell therapy in chronic lymphocytic leukemia (CLL). We studied the possibility and mechanism of the synergistic effect of ibrutinib and CAR‐T cells in other types of lymphoma. In this study, we selected the CD19 CAR‐T cells of a patient with lymphoma who failed in his CD19 CAR‐T‐cell therapy and a dose of 8 mg/kg/d ibrutinib. Subcutaneous and tail vein tumorigenic mice were established with Raji cells. The differences in the synergistic effect between these 2 models were compared by bioluminescence imaging (BLI) monitoring and flow cytometry (FCM). The expression of the STAT‐3 signaling pathway was assessed by western blot analysis. There was no synergistic effect of ibrutinib and CD19 CAR‐T cells in vitro. Programmed cell death‐ligand 1 (PD‐L1) was expressed in 0.23 ± 0.06% of Raji cells. In the subcutaneous tumorigenic model, the luciferase signal was reduced significantly in the group receiving ibrutinib combined with CD19 CAR‐T cells. Moreover, the proportion of CD19 CAR‐T cells was higher in the polytherapy group than in the CAR‐T‐cell monotherapy group. However, we did not get an analogous synergistic effect in the tail vein tumorigenic model. STAT‐3 signaling pathway expression in the residual tumor cells did not differ between those with and those without ibrutinib, suggesting that the IL‐10/STAT‐3/PD‐L1 pathway was not involved in the synergistic effect. Therefore, some other mechanism might be a target for ibrutinib. Our results provide evidence for the use of ibrutinib in polytherapy for other types of B‐cell lymphoma.

Efficacy and safety profiles of programmed cell death-1/programmed cell death ligand-1 inhibitors in the treatment of triple-negative breast cancer: A comprehensive systematic review

Triple-negative breast cancer (TNBC) is associated with worse prognosis, with limited treatment regiments available and higher mortality rate. Immune checkpoint inhibitors targeting programmed cell death-1 (PD-1) or programmed cell death-ligand 1 (PD-L1) showed great potentials in treating malignancies and may serve as potential therapies for TNBC. This systematic review aims to evaluate the efficacy and safety profiles of PD-1/PD-L1 inhibitors in the treatment of TNBC. Literature search was performed via PubMed, EBSCOhost, Scopus, and CENTRAL databases, selecting studies which evaluated the use of anti-PD-1/PDL1 for TNBC from inception until February 2019. Risk of bias was assessed by the Newcastle-Ottawa Scale (NOS). Overall, 7 studies evaluating outcomes of 1395 patients with TNBC were included in this systematic review. Anti-PD-1/PD-L1 showed significant antitumor effect, proven by their promising response (objective response rate (ORR), 18.5-39.4%) and survival rates (median overall survival (OS), 9.2-21.3 months). Moreover, anti- PD-1/PD-L1 yielded better outcomes when given as first-line therapy, and overexpression of PD-L1 in tumors showed better therapeutic effects. On the other hands, safety profiles were similar across agents and generally acceptable, with grade ≥3 treatment- related adverse effects (AEs) ranging from 9.5% to 15.6% and no new AEs were experienced by TNBC patients. Most grade ≥3 AEs are immune-mediated, which are manifested as neutropenia, fatigue, peripheral neuropathy, and anemia. PD-1/PD-L1 inhibitors showed promising efficacy and tolerable AEs, and thus may benefit TNBC patients. Further studies of randomized controlled trials with larger populations are needed to better confirm the potential of these agents.

PD-L1 Expression in Muscle-Invasive Urinary Bladder Urothelial Carcinoma According to Basal/Squamous-Like Phenotype

Urothelial carcinoma (UC) is the most common histologic type of urinary bladder cancer, and muscle-invasive UC shows aggressive behaviors. Programmed cell death-1 (PD-1)/programmed cell death-ligand 1 (PD-L1) blockades have been approved as standard treatments for patients with advanced stage UC. A total of 166 muscle-invasive urinary bladder cancer (MIBC) patients, who underwent transurethral resection of the bladder or cystectomy from 2004 to 2010 were included. We evaluated PD-L1 expression by the SP142 and SP263 assays and classified the cases “positive” or “negative” according to the manufacturer’s recommendations. We performed immunohistochemistry (IHC) for cytokeratin (CK) 5/6, CK14, GATA3, FOXA1, and CK20 and classified samples as Basal-Squamous-like (BASQ) or non-BASQ subtype. The overall concordance rate for PD-L1 expression is 91.6% (152/166) (kappa = 0.732). The SP142 assay showed 15.1% positivity; the SP263 assay showed 23.5%. The high positivity in the SP142 and SP263 assay was significantly correlated with positive CK5/6, CK14 expression, negative GATA3, FOXA1, and CK20 expression. Classification according to IHC expression resulted in 12.0% (20/166) of samples being classified as BASQ subtype and 88.0% (146/166) of samples being classified as non-BASQ subtype. High positivity in the SP142 and SP263 assay was significantly correlated with the BASQ subtype (p < 0.001, both). Our study is the first to analyze the association of immunohistochemically defined BASQ and non-BASQ subtypes with two PD-L1 assays in MIBC. In conclusion, we revealed that a high PD-L1 positive rate in all PD-L1 assays was significantly associated with the BASQ-subtype, and these results suggest that the BASQ classification may be important to apply the PD-1/PD-L1 blockades in MIBC.

Selective Suppression of Cell Growth and Programmed Cell Death-Ligand 1 Expression in HT1080 Fibrosarcoma Cells by Low Molecular Weight Fucoidan Extract

Low molecular weight fucoidan extract (LMF), prepared by an abalone glycosidase digestion of a crude fucoidan extracted from Cladosiphon novae-caledoniae Kylin, exhibits various biological activities, including anticancer effect. Various cancers express programmed cell death-ligand 1 (PD-L1), which is known to play a significant role in evasion of the host immune surveillance system. PD-L1 is also expressed in many types of normal cells for self-protection. Previous research has revealed that selective inhibition of PD-L1 expressed in cancer cells is critical for successful cancer eradication. In the present study, we analyzed whether LMF could regulate PD-L1 expression in HT1080 fibrosarcoma cells. Our results demonstrated that LMF suppressed PD-L1/PD-L2 expression and the growth of HT1080 cancer cells and had no effect on the growth of normal TIG-1 cells. Thus, LMF differentially regulates PD-L1 expression in normal and cancer cells and could serve as an alternative complementary agent for treatment of cancers with high PD-L1 expression.

Prognostic significance of programmed cell death-ligand 1 expression on circulating tumor cells in various cancers: A systematic review and meta-analysis

Background

The prognostic significance of programmed cell death‐ligand 1 (PD‐L1) expression on circulating tumor cells (CTCs) has been explored but is still in controversy. We performed, for the first time, a meta‐analysis to systematically evaluate its prognostic value in human cancers.

Methods

Literature databases were searched for eligible studies prior to June 30, 2021. The pooled hazard ratios (HRs) and 95% confidence intervals (95% CIs) were calculated for the associations of pre‐treatment and post‐treatment PD‐L1⁺ CTCs with progression‐free survival (PFS) and overall survival (OS). Subgroup analyses with regards to cancer type, treatment, CTC enrichment method, PD‐L1 detection method, cut‐off, and specifically the comparison model were performed.

Results

We included 30 eligible studies (32 cohorts, 1419 cancer patients) in our analysis. Pre‐treatment PD‐L1⁺ CTCs detected by immunofluorescence (IF) tended to predict better PFS (HR = 0.55, 95% CI 0.28–1.08, p = 0.084) and OS (HR = 0.61, 95% CI 0.36–1.04, p = 0.067) for immune checkpoint inhibitor (ICI) treatment, but were significantly associated with unfavorable survival for non‐ICI therapies (PFS: HR = 1.85, 95% CI 1.21–2.85, p = 0.005; OS: HR = 2.44, 95% CI 1.69–3.51, p < 0.001). Post‐treatment PD‐L1⁺ CTCs predicted markedly worse PFS and OS. The prognostic value was obviously modulated by comparison models. Among patients with detectable CTCs, PD‐L1⁺ individuals had comparable survival to PD‐L1⁻ individuals, except ICI treatment for which PD‐L1⁺ may predict better PFS (HR = 0.42, 95% CI 0.17–1.06, p = 0.067). Patients with PD‐L1⁺ CTCs had worse survival prognosis compared to those without PD‐L1⁺ CTCs in overall analysis (PFS: HR = 2.10, 95% CI 1.59–2.77, p < 0.001; OS: HR = 2.55, 95% CI 1.70–3.81, p < 0.001) and in most subgroups.

Conclusions

Our analysis demonstrated that PD‐L1 positive expression on CTCs predicted better survival prognosis for ICI treatment but worse survival for other therapies, which thus can be potentially used as a prognostic marker of malignant tumor treatment. However, the prognostic value of PD‐L1⁺ CTCs for ICI treatment needs validation by more large‐scale studies in the future.

Frequency and clinicopathologic associations of DNA mismatch repair protein deficiency in ampullary carcinoma: Routine testing is indicated

BACKGROUND

The significance of DNA mismatch repair (MMR) deficiency in ampullary cancers (ACs) has not been established.

METHODS

In total, 127 ACs with invasive carcinomas measuring ≥3 mmthat had adequate tissue were analyzed immunohistochemically.

RESULTS

MMR loss was detected in 18% of ACs (higher than in colorectal cancers). Twelve tumors with MLH1-PMS2 loss were negative for BRAF V600E mutation, suggesting a Lynch syndrome association. MMR-deficient tumors (n = 23), comparedwith MMR-intact tumors (n = 104), showed a striking male predominance (male:female ratio, 4.7). Although the deficient tumors had slightly larger invasion size (2.7 vs 2.1 cm), they also had more expansile growth and less invasiveness, including less perineural invasion, and they ultimately had lower tumor (T) classification and less lymph node metastasis (30% vs 53%; P = .04). More important, patients who had MMR-deficient tumors had better clinical outcomes, with a 5-year overall survival rate of 68% versus 45% (P = .03), which was even more pronounced in those who had higher Tclassification (5-year overall survival, 69% vs 34%; P = .04). MMR deficiencyhad a statistically significant association with medullary phenotype, pushing-border invasion, and tumor-infiltrating immune cells, and it occurred more frequently in ampullary-duodenal type tumors. Programed cell death-ligand 1 (PD-L1) levels analyzed in the 22 MMR-deficient ACs revealed that all medullary carcinomas were positive. Nonmedullary MMR-deficient carcinomas expressed PD-L1 in 33% of tumors cells according to the criteria for a combined positive score ≥1, but all were negative according to the tumor proportion score≥1 method.

CONCLUSIONS

In ACs, MMR deficiency is even more frequent (18%) than in colon cancer and often has a Lynch-suggestive profile, thus routine testing is warranted. Male gender, pushing-border infiltration, ampullary-duodenal origin, medullary histology, and tumor-related inflammation have a significantly higher association with MMR deficiency. MMR-deficient tumors have less aggressive behavior. PD-L1 expression is common in medullary-phenotype ACs, thus immunotherapy should be considered at least for this group.

Immune checkpoint inhibitor-associated hypercalcaemia

Immune checkpoint inhibitors (CPIs) have recently become a cornerstone for the treatment of different advanced cancers. These drugs have the ability to reactivate the immune system against tumour cells but can also trigger a myriad of side effects, termed immune-related adverse events (irAEs). Although there are numerous reports of CPI-related endocrinopathies, hypercalcaemia as a suspected irAE is not well documented. The mechanisms of CPI hypercalcaemia are not clearly established. However, in our review, four distinct causes emerged: endocrine disease-related, sarcoid-like granuloma, humoral hypercalcaemia due to parathyroid-related hormone and hyperprogressive disease following CPI initiation. Prompt recognition of hypercalcaemia and the institution of therapy can be lifesaving, affording the opportunity to address the underlying aetiology. In this review we discuss the incidence, diagnosis and management of immune-related hypercalcaemia in oncological patients receiving CPI agents.

Epithelial-to-mesenchymal transition and its association with PD-L1 and CD8 in thyroid cancer

Programmed cell death-ligand 1 (PD-L1) has recently been shown to play a role in the regulation of epithelial-to-mesenchymal transition (EMT); however, the relationship between PD-L1 expression, EMT and the inflammatory tumour microenvironment has yet to be investigated in thyroid cancer. To address this issue, we examined the expression of CD8, PD-L1 and the EMT markers E-cadherin and vimentin in a cohort of 74 papillary thyroid cancer (PTC) patients and investigated the association of these with clinicopathologic characteristics and disease-free survival (DFS). The relationship between PD-L1 and EMT was further examined in three thyroid cancer cell lines via Western blot and live cell imaging. In order to expand our in vitro findings, the normalised gene expression profiles of 516 thyroid cancer patients were retrieved and analysed from The Cancer Genome Atlas (TCGA). PD-L1 positivity was significantly higher in PTC patients exhibiting a mesenchymal phenotype (P = 0.012). Kaplan-Meier analysis revealed that PD-L1 (P = 0.045), CD8 (P = 0.038) and EMT status (P = 0.038) were all significant predictors for DFS. Sub-analysis confirmed that the poorest DFS was evident in PD-L1 positive patients with EMT features and negative CD8 expression (P < 0.0001). IFN-γ treatment induced upregulation of PD-L1 and significantly promoted an EMT phenotype in two thyroid cancer cell lines. Our findings suggest that PD-L1 signalling may play a role in stimulating EMT in thyroid cancer. EMT, CD8 and PD-L1 expression may serve as valuable predictive biomarkers in patients with PTC.

Formalin fixation for optimal concordance of programmed death-ligand 1 immunostaining between cytologic and histologic specimens from patients with non-small cell lung cancer

BACKGROUND

Immunohistochemical staining of programmed death-ligand 1 (PD-L1) is used to determine which patients with non-small cell lung cancer (NSCLC) may benefit most from immunotherapy. Therapeutic management of many patients with NSCLC is based on cytology instead of histology. In this study, concordance of PD-L1 immunostaining between cytology cell blocks and their histologic counterparts was analyzed. Furthermore, the effect of various fixatives and fixation times on PD-L1 immunoreactivity was studied.

METHODS

Paired histologic and cytologic samples from 67 patients with NSCLC were collected by performing fine-needle aspiration on pneumonectomy/lobectomy specimens. Formalin-fixed, agar-based or CytoLyt/PreservCyt-fixed Cellient cell blocks were prepared. Sections from cell blocks and tissue blocks were stained with SP263 (standardized assay) and 22C3 (laboratory-developed test) antibodies. PD-L1 scores were compared between histology and cytology. In addition, immunostaining was compared between PD-L1-expressing human cell lines fixed in various fixatives at increasing increments in fixation duration.

RESULTS

Agar cell blocks and tissue blocks showed substantial agreement (κ = 0.70 and κ = 0.67, respectively), whereas fair-to-moderate agreement was found between Cellient cell blocks and histology (κ = 0.28 and κ = 0.49, respectively). Cell lines fixed in various alcohol-based fixatives showed less PD-L1 immunoreactivity compared with those fixed in formalin. In contrast to SP263, additional formalin fixation after alcohol fixation resulted in preserved staining intensity using the 22C3 laboratory-developed test and the 22C3 pharmDx assay.

CONCLUSIONS

Performing PD-L1 staining on cytologic specimens fixed in alcohol-based fixatives could result in false-negative immunostaining results, whereas fixation in formalin leads to higher and more histology-concordant PD-L1 immunostaining. The deleterious effect of alcohol fixation could be reversed to some degree by postfixation in formalin.

Prognostic value of PD-L1 expression in resected lung adenocarcinoma and potential molecular mechanisms

Background: The prognostic role of PD-L1 expression in surgically resected lung adenocarcinoma (ADC) remains controversial. The present study was aimed to clarify the role of PD-L1 expression in predicting prognosis and to investigate its biological function in ADC.

Materials and Methods: The association between PD-L1 expression and clinical outcomes in patients with resected ADC was analyzed using immunohistochemistry (IHC) in our cohort (n=104), externally validated by a meta-analysis of 13 published studies. The biological role of PD-L1 in ADC was explored using gene set enrichment analysis (GSEA).

Results: Positive PD-L1 expression in tumor cells was observed in 38.5% (40/104). High PD-L1 expression levels were significantly correlated with poor overall survival (P=0.008). Furthermore, the meta-analysis also showed that positive PD-L1 expression was associated with shorter OS than negative PD-L1 expression (HR= 1.75, 95% CI: 1.26-2.42; P<0.001). In subgroup analysis stratified according to ethnicity, the pooled results demonstrated that increased PD-L1 expression was an unfavorable prognostic factor for Asian populations (HR= 2.11, 95% CI: 1.48-3.02; P<0.001), but not for non-Asian populations (HR=1.16, 95% CI: 0.63-2.11, P=0.64). The pooled odds ratios (ORs) indicated that PD-L1 expression was associated with positive lymph node metastasis (OR=1.74, 95% CI: 1.23-2.46; P=0.002) and male (OR=1.56, 95% CI: 1.02-2.37; P=0.04). GSEA revealed PD-L1 expression levels positively correlated with immune process or immune-related pathways.

Conclusion: PD-L1 expression is an important negative prognostic factor in resected ADC. This finding has important implications for immunotherapy targeting the PD-1/PD-L1 pathway in patients with resected ADC.

Programmed cell death-ligand 1 expression and immunoscore in stage II and III non-small cell lung cancer patients receiving adjuvant chemotherapy

Programmed cell death 1 (PD-1) receptor–ligand interaction is a major pathway that is often hijacked by tumors to suppress immune control. Immunoscore (IS), a combinational index of CD3 and CD8 tumor-infiltrating lymphocyte (TIL) density in the tumor’s center and invasive margin, is a new prognostic tool suggested to be superior to conventional tumor-staging methods in various tumors. This retrospective study aimed to investigate the prevalence and prognostic roles of PD-ligand 1 (PD-L1) expression and IS in non-small cell lung cancer (NSCLC) patients receiving adjuvant chemotherapy. PD-L1 expression and TIL density were evaluated by immunohistochemical analysis in 36 patients with stage II and III NSCLC. Tumors with staining in over 1% of their cells were scored as positive for PD-L1 expression, and we determined the median number of CD3- and CD8-positive TILs as the cutoff point for TIL density. To determine IS, each patient was given a binary score (0 for low and 1 for high) for CD3 and CD8 density in both the tumor center and invasive margin region. PD-L1 expression in tumor cells was observed in 61.1% (22/36) of patients. PD-L1 expression was significantly associated with high IS, and highest IS tended to have a favorable disease-free survival.

High PD-L1 Expression on Tumor Cells Indicates Worse Overall Survival in Advanced Oral Squamous Cell Carcinomas of the Tongue and the Floor of the Mouth but Not in Other Oral Compartments

The markers of the tumor microenvironment (TME) are promising prognostic and predictive factors in oral squamous cell carcinoma (OSCC). The current study aims to analyze the immunohistochemical expression of programmed cell death-ligand 1 (PD-L1) and interleukin-33 (IL-33) in a cohort of 95 chemonaïve OSCCs. PD-L1 and IL-33 were assessed separately in tumor cells (TCs) and tumor-infiltrating lymphocytes (TILs). High PD-L1 expression in TILs was associated with better overall survival (OS) in univariate analysis. Tumors localized in the floor of the oral cavity and tongue tended to have a lower percentage of PD-L1-positive TCs when compared to other locations. PD-L1 expression on TCs had no prognostic significance when the whole cohort was analyzed. However, along with the T descriptor (TNM 8th), it was included in the multivariable model predicting death in carcinomas of the floor of the oral cavity and tongue (HR = 2.51, 95% CI = 1.97-5.28). In other locations, only nodal status was identified as an independent prognostic factor in multivariate analysis (HR = 0.24, 95% CI = 0.08-0.70). Expression of IL-33 had no impact on survival, but it was differently expressed in various locations. In conclusion, the prognostic significance of PD-L1 in oral cancer depends on the tumor site and type of cell expressing immune checkpoint receptor (TCs vs. TILs).