Changes In Programmed Death Ligand 1 Expression Research Articles

Enhanced Electrochemical Characterization of the Immune Checkpoint Protein PD-L1 using Aptamer-Functionalized Magnetic Metal-Organic Frameworks.

Programmed death ligand 1 (PD-L1) is highly expressed in cancer cells and participates in the immune escape process of tumor cells. However, as one of the most promising biomarkers for cancer immunotherapy monitoring, the key problem ahead of practical usage is how to effectively improve the detection sensitivity of PD-L1. Herein, an electrochemical aptasensor for the evaluation of tumor immunotherapy is developed based on the immune checkpoint protein PD-L1. The fundamental principle of this method involves the utilization of DNA nanotetrahedron (NTH)-based capture probes and aptamer-modified magnetic metal-organic framework nanocomposites as signaling probes. A synergistic enhancement is observed in the electrocatalytic effect between Fe3O4 and UiO-66 porous shells in Fe3O4@UiO-66 nanocomposites. Therefore, the integration of aptamer-modified Fe3O4@UiO-66@Au with NTH-assisted target immobilization as an electrochemical sensing platform can significantly enhance sensitivity and specificity for target detection. This method enables the detection of targets at concentrations as low as 7.76 pgmL-1 over a wide linear range (0.01 to 1000ngmL-1). The authors have successfully employed this sensor for in situ characterization of PD-L1 on the cell surface and for monitoring changes in PD-L1 expression during drug therapy, providing a cost-effective yet robust alternative to highly expensive and expertise-dependent flow cytometry.

Non-invasive PD-L1 quantification using [18F]DK222-PET imaging in cancer immunotherapy

BackgroundCombination therapies that aim to improve the clinical efficacy to immune checkpoint inhibitors have led to the need for non-invasive and early pharmacodynamic biomarkers. Positron emission tomography (PET) is a...

Implication of changes in PD-L1 expression during neoadjuvant chemotherapy with docetaxel, cisplatin, and 5-fluorouracil (DCF) regimen in esophageal squamous cell carcinoma.

Neoadjuvant docetaxel plus cisplatin and 5-FU (NAC-DCF) and adjuvant nivolumab monotherapy are the standard care for locally advanced resectable esophageal squamous cell carcinoma (ESCC). However, no effective biomarkers have been found in perioperative setting. We investigated how programmed death-ligand 1 (PD-L1) changes before and after NAC-DCF and how it relates to the therapeutic effect of NAC-DCF in resectable ESCC. PD-L1 expression in paired diagnostic biopsy and surgically resected tissues from ESCC patients who underwent surgical resection after receiving two or three NAC-DCF cycles was evaluated. PD-L1 positivity was defined as a combined positive score (CPS) of 10% ≤ . Gene expression analysis was conducted using samples before NAC-DCF. Sixty-six paired samples from 33 patients were included in PD-L1 expression analysis, and 33 Pre-NAC samples acquired by diagnostic biopsy were included in gene expression analysis. Pretreatment, 3 (9%), 13 (39%), and 17 (52%) patients harbored tumors with CPS ranges of < 1%, 1%-10%, and 10% ≤ , respectively. After NAC-DCF, 5 (15%), 15 (45%), and 13 (39%) tumors presented CPS ranges of < 1%, 1%-10%, and 10% ≤ , respectively. The concordance rate between Pre-and Post-NAC-DCF samples was 45%. Patients with PD-L1-negative tumors both before and after NAC-DCF (n = 9) had shorter survival and different gene expression profile characterized by upregulation in WNT signaling or neutrophils. A substantial PD-L1 expression alteration was observed, resulting in low concordance rate before and after NAC-DCF. Tumors persistently lacking PD-L1 had distinct gene expression profile with worse clinical outcomes, raising the need for further investigation.

Novel small 99mTc-labeled affibody molecular probe for PD-L1 receptor imaging.

The in vivo imaging of programmed death ligand 1 (PD-L1) can monitor changes in PD-L1 expression and guide programmed death 1 (PD-1) or PD-L1-targeted immune checkpoint therapy. A 99mTc-labeled affibody molecular probe targeting the PD-L1 receptor was prepared and evaluated its tracing effect in PD-L1-overexpressing colon cancer. The PD-L1 affibody was prepared by genetic recombineering. The 99mTc labeling of the affibody was achieved by sodium glucoheptonate and an SnCl2 labeling system. The labeling rate, radiochemical purity, and stability in vitro were determined by instant thin-layer chromatography; MC38-B7H1 (PD-L1-positive) and MC38 (PD-L1-negative) colon cancer cells were used to evaluate its affinity to PD-L1 by cell-binding experiments. The biodistribution of the 99mTc-labeled affibody molecular probe was then determined in C57BL/6J mice bearing MC38-B7H1 tumors, and tumor targeting was assessed in C57BL/6J mice with MC38-B7H1, MC38 double xenografts. The nondecayed corrected yield of the 99mTc-PD-L1 affibody molecular probe was 95.95% ± 1.26%, and showed good stability both in phosphate-buffered saline (PBS) and fetal bovine serum within 6h. The affinity of the 99mTc-PD-L1 affibody molecular probe for cell-binding assays was 10.02 nmol/L. Single photon emission-computed tomography imaging showed a rapid uptake of the tracer in PD-L1-positive tumors and very little tracer retention in PD-L1-negative control tumors. The tracer was significantly retained in the kidneys and bladder, suggesting that it is mainly excreted through the urinary system. Heart, liver, lung, and muscle tissue showed no significant radioactive retention. The biodistribution in vitro also showed significant renal retention, a small amount of uptake in the thyroid and gastrointestinal tract, and rapid blood clearance, and the tumor-to-blood radioactivity uptake ratio peaked 120min after drug injection. The 99mTc-PD-L1 affibody molecular probe that we prepared can effectively target to PD-L1-positive tumors imaging in vivo, and clear in blood quickly, with no obvious toxic side effects, which is expected to become a new type of tracer for detecting PD-L1 expression in tumors.

Combined treatment with anti-PSMA CAR NK-92 cell and anti-PD-L1 monoclonal antibody enhances the antitumour efficacy against castration-resistant prostate cancer.

BackgroundThe chimeric antigen receptor NK‐92 (CAR NK‐92) cell targeting the prostate‐specific membrane antigen (PSMA) has shown antitumour effects in castration‐resistant prostate cancer (CRPC). However, the expression changes of programmed death ligand 1 (PD‐L1) and its mechanisms on CAR NK‐92 and CRPC cells and the effect of the anti‐PD‐L1 monoclonal antibody (mAb) on PD‐L1 expressed on CAR NK‐92 cells remain unknown.MethodsHuman dendritic cells and CD8+ T cells were acquired from blood samples of healthy donors and cocultured with C4‐2 cells. Changes in PD‐L1 expression were detected by flow cytometry. Differential gene expressions were investigated by RNA sequence analysis, while the regulation of PD‐L1 molecular signaling was explored using western blotting. In vitro cytotoxicity was evaluated using the Cell Counting Kit‐8 assay and the bioluminescent intensity (BLI) of green fluorescent protein‐labelled C4‐2 cells. CRPC growth in vivo was monitored using callipers and BLI in male NOD/SCID mice subcutaneously injected with C4‐2 cells and treated intravenously with anti‐PD‐L1/PD‐1 mAb, CAR NK‐92 or cocultured CD8+ T cells.ResultsSignificantly upregulated expression of PD‐L1k was observed in cocultured C4‐2 and CAR NK‐92 cells. In addition, upregulation of PD‐L1 expression was dependent on interferon‐γ in C4‐2 cells, while it was dependent on direct cell‐to‐cell interaction via the NK group 2 member D/ phosphatidylinositol 3‐kinase/AKT pathway in CAR NK‐92 cells. The anti‐PD‐L1 mAb directly acted on PD‐L1 expressed on CAR NK‐92 cells and augmented the cytotoxicity of CAR NK‐92 cells against C4‐2 and CRPC cells from one patient in vitro. Anti‐PD‐L1 mAb significantly enhanced the antitumour effect of CAR NK‐92 cells against CRPC cells in vivo when compared to treatment with CAR NK‐92 cells or combined with anti‐PD‐1 mAb in the absence or presence of cocultured CD8+ T cells.ConclusionCombined treatment with CAR NK‐92 and anti‐PD‐L1 mAb improved the antitumour efficacy against CRPC, which is of extraordinary translational value in the clinical treatment of CRPC.

Increase in tumour PD-L1 expression in non-small cell lung cancer following bronchoscopic thermal vapour ablation.

Limited early evidence indicates thermal ablation of non-small cell lung cancer (NSCLC) may induce alterations to the immune response that could enhance the efficacy of immunotherapy with immune checkpoint inhibitor therapy. This study reports pilot data demonstrating increased programmed death-ligand 1 (PD-L1) expression on tumour cells in response to bronchoscopic thermal vapour ablation. Five patients underwent bronchoscopic thermal vapour ablation under a treat-and-resect protocol, as part of a clinical safety and feasibility study, with lobectomy performed five days after thermal vapour ablation. PD-L1 (clone SP263) immunohistochemistry (IHC) tumour proportion score (TPS) was assessed on both baseline diagnostic biopsy specimens, and post-ablation resection specimens in five patients with stage I NSCLC. Two areas of the resection sample defined as viable tumour and injured tumour were examined. All tumours demonstrated 0% PD-L1 TPS at baseline. Three of five (60%) patients demonstrated an increase in PD-L1 TPS in areas of injured tumour to 20%, 30% and 50%. One patient demonstrated an increase in PD-L1 expression in an area of viable tumour to 5%. Changes in PD-L1 expression did not correlate with measures of systemic inflammation. Our findings comprise the first evidence that thermal ablation of NSCLC may induce PD-L1 expression. Further investigation is required to determine the extent of an adaptive immune response, and confirm the potential for augmentation of clinical response to immune check point inhibitor therapy in NSCLC.

Temporal evolution of programmed death-ligand 1 expression in patients with non-small cell lung cancer.

Background/AimsProgrammed death-ligand 1 (PD-L1) expression, a validated predictive biomarker for anti-PD-1/PD-L1 inhibitors, is reported to change over time. This poses challenges during clinical application in non-small cell lung cancer.MethodsThis study included patients with non-small cell lung cancer who underwent surgery or biopsy and evaluation of PD-L1 expression in tumor cells via immunohistochemistry more than twice. We set the threshold of PD-L1 positivity to 10% and categorized patients into four groups according to changes in PD-L1 expression. Clinicopathologic information was collected from medical records. Statistical analyses, including Fisher’s exact test and log-rank test, were performed.ResultsOf 109 patients, 38 (34.9%) and 45 (41.3%) had PD-L1 positivity in archival and recent samples, respectively. PD-L1 status was maintained in 78 (71.6%) patients, but changed in 31 (28.4%), with 19 (17.4%) from negative to positive. There were no significant differences in characteristics between patients who maintained PD-L1 negativity and whose PD-L1 status changed from negative to positive. Patients harboring PD-L1 positivity in either archival or recent samples achieved better responses (p = 0.129) and showed longer overall survival than those who maintained PD-L1 negativity when they received immune checkpoint inhibitors after platinum failure (median overall survival 14.4 months vs. 4.93 months; hazard ratio, 0.43; 95% confidence interval, 0.20 to 0.93).ConclusionsPD-L1 status changed in about one-fourth of patients. PD-L1 positivity in either archival or recent samples was predictive of better responses to immune checkpoint inhibitors. Therefore, archival samples could be used for assessment of PD-L1 status. The need for new biopsies should be decided individually.

Immunotherapy and chemotherapy combination for chest wall disease: TBCRC 044 trial.

TPS1114 Background: Immunotherapy combined with chemotherapy is being studied in metastatic breast cancer, and may have durable outcomes. Chest wall recurrence represents a difficult to treat subtype of breast cancer with a poor prognosis, with lymphovascular invasion in the primary tumor a significant risk factor. Given the inflammatory nature of this disease and the association of programmed cell death 1 (PD-1) expression with lymphovascular invasion, we hypothesized that the combination of pembrolizumab, an anti-PD-1 antibody, with carboplatin may be effective as treatment for breast cancer chest wall recurrences. Methods: This randomized phase II study is enrolling 84 patients with breast cancer involving the chest wall, who may also have distant metastases. Patients receive treatment with pembrolizumab 200 mg and carboplatin AUC 5 every 3 weeks for 6 cycles (Arm A, n = 56) followed by maintenance pembrolizumab +/- carboplatin (Arm Ax), or carboplatin AUC 5 every 3 weeks for 6 cycles (Arm B, n = 28) with an option to cross-over to pembrolizumab +/- carboplatin on progression (Arm Bx). Patients with all disease subtypes, triple-negative, hormone receptor positive/HER2- after 2 prior lines of hormone therapy, and HER2+ disease (with the option to continue trastuzumab) are eligible, with no limit on the number of prior therapies. Prior platinum chemotherapy is allowed in the absence of overt disease progression. Patients undergo clinical assessment with every cycle of treatment including chest wall photography, scans (CT chest, abdomen, and pelvis) every 2 cycles, and have peripheral blood and chest wall biopsies collected at baseline and the start of cycle 3 for correlative studies. The primary endpoint is the disease control rate in the chest wall and distant sites at 18 weeks of treatment based on RECIST 1.1. The study is powered to determine a 20% difference in disease control between arms (hazard ratio 0.52, α = 0.10, β = 0.20). Additional endpoints include response by tumor programmed death ligand 1 (PD-L1) status and irRECIST, progression-free survival, and toxicity. Chest wall tumor samples will be analyzed for changes in tumor immune composition, and PD-L1 and MYC oncogene expression, based on preclinical data to suggest that PD-L1 may be upregulated by MYC. Peripheral blood samples will be evaluated for changes in PD-L1 expression, cell-free DNA, and circulating tumor cells with treatment. The study is enrolling patients at 7 sites within the Translational Breast Cancer Research Consortium (TBCRC), with current enrollment of 38/84 patients. Clinical trial information: NCT03095352 .

Treatment Results for Recurrent Glioblastoma and Alteration of Programmed Death-Ligand 1 Expression After Recurrence

This study was designed to analyze the results of recurrent glioblastoma (GBM) treatment, investigate the changes in molecular expression on paired primary and recurrent tumor specimens of GBM, and evaluate the effect of these changes on patient survival. A total of 170 adult patients were diagnosed with recurrent GBM at a single institution between 2005 and 2015. Patients were divided into the reoperation and nonoperation groups. In addition, we evaluated the expression of immunologic markers of 43 paired surgical specimens from the first and second operations. The median overall survival (OS) after recurrence in the reoperation group was significantly longer than that in the nonoperation group (median, 9.1 months vs. 5.6 months; P= 0.024). The groups differed in characteristics such as age, performance scale, and progression-free survival. In the reoperation group, higher performance scale at recurrence, better extent of resection, and adjuvant treatment were related to longer overall survival. Among 43 paired surgical specimens, programmed death-ligand 1 (PD-L1) was positively expressed in 17 (39.5%) and 6 (13.9%) patients after the first and second operations, respectively. PD-L1 expression after recurrence showed an increase, decrease, and no change in 6 (13.9%), 14 (32.5%), and 23 (53.4%) patients, respectively. Changes in PD-L1 expression after recurrence did not affect survival after recurrence during progression. The extent of resection and adjuvant treatment was important for prolonged survival. Reoperation without adjuvant treatment was not effective for prolonged survival. Initial and follow-up PD-L1 expression from both operations did not influence patient survival.

Dynamic changes in PD-L1 expression and CD8+ T cell infiltration in non-small cell lung cancer following chemoradiation therapy

ObjectivesThe treatment for stage III non-small cell lung cancer (NSCLC) is quite variable because stage III NSCLC is a heterogenous disease. Programmed death ligand 1 (PD-L1) and CD8+ tumor infiltrating lymphocytes (TILs) are thought to be related to treatment outcome in many tumors. To improve treatment outcome in stage III NSCLC, it is necessary to obtain data on PD-L1 expression and CD8+ TIL counts following CCRT and their relationship to treatment outcome. Materials and methodsWe retrospectively enrolled 43 patients with stage III NSCLC treated with neoadjuvant CCRT followed by surgery at Yonsei Cancer Center Severance Hospital in Korea between June 2008 and October 2010. PD-L1 level and CD8+ TIL numbers in tumors following CCRT were analyzed by immunohistochemistry, and their association with patient survival was evaluated with Kaplan-Meier method. ResultsMore than half patients (52%) showed up- or downregulation of PD-L1 expression, and most patients (81%) showed change in CD8+ TIL counts by CCRT. Patients with PD-L1 expression following CCRT tended to have shorter recurrence free survival (RFS) (P = 0.182) or overall survival (OS) (P = 0.215) compared to the ones without PD-L1 expression. In the survival analysis with pre-CCRT specimens, neither RFS nor OS showed statistically significant differences. Patients with increased CD8+ TIL counts following CCRT regardless of pathological response strongly showed longer OS (median: not reached vs. 14.2 months for others; P = 0.017). ConclusionsCCRT dynamically alters PD-L1 expression and CD8+ TIL numbers in stage III NSCLC. Our data provide a rationale for combining CCRT and immunotherapy for the treatment of potentially resectable NSCLC.

Adjuvant Chemotherapy Increases Programmed Death-Ligand 1 (PD-L1) Expression in Non–small Cell Lung Cancer Recurrence

BackgroundDespite recent studies, the effect of chemotherapy on programmed death-ligand 1 (PD-L1) expression remains controversial. In this study, we investigated whether PD-L1 expression is affected by platinum-based chemotherapy. Furthermore, we evaluated correlation of PD-L1 expression with oncogenic driver alterations. Materials and MethodsWe retrospectively evaluated changes in PD-L1 expression by immunohistochemical (IHC) analysis in resected specimens and in biopsies at non–small cell lung cancer recurrence in patients receiving or not adjuvant chemotherapy after surgical resection. Four IHC score groups were defined: TC0 < 1%, T ≥ 1% and < 5%, TC2 ≥ 5% and < 50%, and TC3 ≥ 50%. ResultsThirty-six patients with adenocarcinoma were included. Twenty (56%) patients underwent adjuvant chemotherapy, and 16 (44%) patients did not receive adjuvant chemotherapy. PD-L1 expression was present in 10 (28%) of 36 initial tumor specimens. From patients receiving adjuvant chemotherapy, 7 (35%) of 20 tumor biopsies showed significant upregulation in PD-L1 expression at recurrence. In contrast, from patients with no adjuvant therapy, only 2 (12.5%) of 16 showed a change in PD-L1 expression. Six (17%) of 36 patients were PD-L1-negative in the primary tumor and turned positive at recurrence. KRAS mutation was present in 70% of patients expressing PD-L1. ConclusionPD-L1 expression in non–small cell lung cancer can change from primary to recurrence, implicating the need for re-biopsy at recurrence. Moreover, chemotherapy might increase expression of PD-L1, supporting a combinatorial therapy with chemotherapy and anti-PD(L)1 treatment.

Near‐infrared fluorescence‐labeled anti‐PD‐L1‐mAb for tumor imaging in human colorectal cancer xenografted mice

The expression of programmed death ligand‐1 (PD‐L1) in tumor has been used as a biomarker to predict the anti‐PD‐L1 immunotherapy response. To develop a noninvasive imaging technique to monitor the dynamic changes in PD‐L1 expression in colorectal cancer (CRC), we labeled an anti‐PD‐L1 monoclonal antibody with near‐infrared (NIR) dye and tested the ability of the NIR‐PD‐L1‐mAb probe to monitor the PD‐L1 expression in CRC‐xenografted mice by performing optical imaging. Consistent with the expression levels of PD‐L1 protein in three CRC cell lines in vitro by flow cytometry and Western blot analyses, our in vivo imaging showed the highest fluorescence signal of the xenografted tumors in mice bearing SW620 CRC cells, followed by tumors derived from SW480 and HCT8 cell lines. We detected the highest fluorescent intensity of the tumor at 120 hours after injection of NIR‐PD‐L1‐mAb. The highest fluorescence intensity was seen in the tumor, followed by the spleen and the liver in SW620 xenografted mice. In SW480 and HCT8 xenografted mice, however, the highest fluorescent signals were detected in the spleen, followed by the liver and the tumor. Our findings indicate that SW620 cells express a higher level of PD‐L1, and the NIR‐PD‐L1‐mAb binding to PD‐L1 on the surface of CRC cells was specific. The technique was safe and could provide valuable information on PD‐L1 expression of the tumor for development of a therapeutic strategy of personized targeted immunotherapies as well as treatment response of patients with CRC.

Changes in programmed death ligand 1 expression in non-small cell lung cancer patients who received anticancer treatments.

The expression of programmed death ligand 1 (PD-L1) is considered a predictive biomarker of anti-programmed death 1 (PD-1)/PD-L1 cancer therapies. However, changes in PD-L1 expression of tumor cells during clinical courses have not been fully evaluated. We evaluated changes in PD-L1 expression for non-small cell lung cancer (NSCLC) patients who received anticancer treatments during clinical courses. In 76 NSCLC patients, PD-L1 expression was evaluated before and after anticancer treatment by immunohistochemical (IHC) analysis using an anti-PD-L1 antibody. We defined two cut-off points of PD-L1 expression (1 and 50%) and three corresponding IHC groups (A: 0%, B: 1-49%, and C: ≥50%). IHC group B and C were considered to be positive expression, and we defined the difference of IHC group between pre- and post-treatment as 'major change' in PD-L1 expression. Before anticancer treatment, PD-L1 expression was observed in 38/76 (50%) patients, and was significantly less common in patients harboring mutations in the epidermal growth factor receptor gene (EGFR) than in those without (P = 0.039). After anticancer treatment, PD-L1 expression was observed in 36/76 (47%) patients. Major increases in PD-L1 expression were seen in 11 (14%), and major decreases in 18 (24%) patients. Among 13 patients harboring EGFR mutations treated with EGFR tyrosine-kinase inhibitor (EGFR-TKI), five (38%) showed major increases. Major changes of PD-L1 expression in tumor cells were observed in 38% of NSCLC patients who received anticancer treatments. And, treatments with EGFR-TKI may increase PD-L1 expression in NSCLC patients harboring EGFR mutations.

Changes in programmed death-ligand 1 expression during cisplatin treatment in patients with head and neck squamous cell carcinoma.

Programmed death-ligand 1 (PD-L1) expression is regarded as a predictive marker for anti-PD-1/PD-L1 therapy. The purpose of study was to explore the changes in PD-L1 expression in head and neck squamous cell carcinoma (HNSCC) during treatment. Paired HNSCC tissues prior to and after cisplatin-based treatment were evaluated to determine PD-L1 protein expression by immunohistochemistry. Among the 35 HNSCC patient samples, PD-L1 expression status changed after treatment in 37.1% (13/35) of samples. Among the 13 patients whose baseline PD-L1 was negative, PD-L1 expression was increased in 9 cases (69.2%) and remained negative in 4 cases (30.8%, P = 0.003). Patients exposed to cisplatin generally showed PD-L1 up-regulation (83.3%, P = 0.037) compared to those not exposed to cisplatin (57.1%, P = 0.072). To validate these findings in vitro, changes in PD-L1 expression in HNSCC cell lines (Detroit-562, PCI-13, SNU-1041, SNU-1066, SNU-1076, and FaDu) were analyzed by western blotting and flow cytometry after treatment with cisplatin and interferon-gamma. In HNSCC cell lines, PD-L1 expression was significantly up-regulated after cisplatin, along with phosphor-MAPK/ERK kinase up-regulation. In conclusion, PD-L1 expression in HNSCC may be altered during cisplatin treatment, activating the MAPK/ERK kinase pathway.

Abstract 4254: Changes in PD-L1 expression during cisplatin containing treatment in patients with head and neck squamous cell carcinoma, and their association with epithelial-mesenchymal transformation

Abstract Background: Programmed death-ligand 1 (PD-L1) expression is regarded as a predictive marker to anti-PD-1/ PD-L1 therapy. However, the underlying mechanism of PD-L1 up-regulation has been poorly defined. The purposes of study are to explore 1) the changes of PD-L1 expression in head and neck squamous cell carcinoma (HNSCC) during cisplatin containing treatment, and 2) PD-L1 up-regulation related genetic alteration. Methods: We compared PD-L1 expressions by immunohistochemisty (IHC, score 0-3) with rabbit anti-PD-L1 antibody (E1L3N) XP (Cell Signaling Technology, Danvers, MA, USA) of 33 baseline tissue samples of HNSCC and 17 paired follow-up tissue samples after ciaplain containing treatment. Baseline PD-L1 expression as well as a change of PD-L1 expression were analyzed with overall survival (OS) of the patients. Changes of PD-L1 expressions in HPV-negative PD-L1 positive HNSCC cell lines (SNU-1066, SNU-1076, Detroit-562) were also analyzed by flow cytometry after various dose of cisplatin treatment. RNA sequencing (RNAseq) of eight HNSCC cell lines was analyzed to find genes of significant correlation with PD-L1 expression by regression method. RNA expression of PD-L1 was assayed by comparing ranks of fragments per kilobase of transcript per million. Results: Among the 17 patients who had paired samples after cisplatin containing treatment, PD-L1 expressions of HNSCC tumor were changed in 10 patients (58.8%). PD-L1 expressions were decreased in 5 patients, and increased in 5 patients. We analyzed changes of PD-L1 expression in 3 HPV negative PD-L1 positive HNSCC cell lines, In vitro, PD-L1 expression was up-regulated after cisplatin treatment in dose-dependent manner (1-10 micromole/L for 24 hours). RNA expression profile by RNAseq of 8 HNSCC cell lines showed that PD-L1 expression was significantly correlated with expression level of epithelial-mesenchymal transformation (EMT) related genes. Expression of epithelial markers such as EPCAM, E-cadherin, SYK, and MUC1 were decreased as PD-L1 expression increased, in contrast, the positive correlations between PD-L1 and mesenchymal markers such as Vimentin, ADAM12, FGF2, and FGFR1 were observed. Conclusion: PD-L1 expression in HNSCC can be changed during cisplatin containing treatment in more than half of patients. When considering anti PD-1/ PD-L1 therapy, PD-L1 expression should be evaluated using most recent biopsy. In vitro, PD-L1 expression was induced in response to cisplatin, and it was correlated with EMT related gene expression. Citation Format: Chan-Young Ock, Bhumsuk Keam, Sehui Kim, Jong-Yeon Shin, Yong-Oon Ahn, Tae Min Kim, Yoon Kyung Jeon, Se-Hoon Lee, Dong-Wan Kim, Dae Seog Heo. Changes in PD-L1 expression during cisplatin containing treatment in patients with head and neck squamous cell carcinoma, and their association with epithelial-mesenchymal transformation. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4254. doi:10.1158/1538-7445.AM2015-4254

Changes in PD-L1 expression in non-small cell lung cancer by immunohistochemical analysis.

e22118 Background:Expression of Programmed Death Ligand-1 (PD-L1) is considered a predictive biomarker of anti-PD-1/PD-L1 therapies. In melanoma with BRAF mutations, it was reported that PD-L1 expr...