Programmed Death Ligand 1 Immunoexpression Research Articles

Evaluation of CTLA-4 and PD-L1 Expression in Thyroid Carcinoma and Its Prognostic Significance.

Introduction Immune checkpoint inhibitors (ICIs) targeting cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4) and programmed death-ligand 1 (PD-L1) have revolutionised treatment and improved outcomes in various malignancies. We aimed to evaluate CTLA-4 and PD-L1 immunoexpression in thyroid tumours and correlated them with clinicopathological parameters. Methods The study included 90 cases of thyroid malignancies comprising papillary thyroid carcinoma (PTC) (n = 64, 54.2%), follicular thyroid carcinoma (FTC) (n = 19, 16.1%), anaplastic thyroid carcinoma (ATC) (n = 3, 2.5%), and poorly differentiated carcinoma (n = 4, 3.4%), two cases (1.69%) of non-invasive follicular thyroid neoplasm with papillary-like nuclear features(NIFTP) along with 26 cases (22%) of benign thyroid lesions. CTLA-4 (UMAB249) and PD-L1 (SP263) expression were assessed in all the cases of thyroid tumours. Results were compared with clinicopathologic parameters and overall survival. Results PD-L1 was positive in all three cases of anaplastic thyroid carcinoma (ATC), 33% (n = 21) cases of PTC, and 16% (n = 3) cases of FTC. PD-L1 positivity was significantly associated at tumour proportion score (TPS) ≥1% with lymphovascular invasion and age ≤40 years and at TPS ≥50% with tumour necrosis and N-stage. Immune proportion score (IPS) did not correlate with any clinicopathological parameters except for the N-stage. CTLA-4 was positive in six cases of PTC (1-5%); five showed lymph node involvement (p = 0.032). IPS was positive in 14 cases, and a significant association was seen with lymph node metastasis, lymphocytic infiltration, and lymphovascular invasion. Three cases of PTC showed co-expression for PD-L1 and CTLA-4 in tumour cells. No significant association was seen between PD-L1 expression and survival. Conclusion The current data suggest that PD-L1 is expressed in differentiated thyroid carcinoma, mainly PTC and ATC, indicating higher responsiveness to immunotherapy. A subset of PTC showed co-expression of PD-L1 and CTLA-4. These findings suggest the need for further investigation to utilise combinational immunotherapy, including anti-PD-L1 and anti-CTLA-4.

Assessment of programmed death ligand 1 (PD-L1) expression in cervical intraepithelial neoplasia and carcinoma cervix

BackgroundCarcinoma cervix is a significant public health issue in low- and middle-income nations. Despite the availability of aggressive cytological screening tests and increasing accessibility of the Human Papilloma Virus vaccine, a significant proportion of patients in our country still present with locally advanced cervical cancer. The objective of this study was to estimate the prevalence of programmed death ligand 1 (PD-L1) immunoexpression in cervical intraepithelial neoplasia and carcinoma cervix and study the distribution of clinicopathological features and recurrence of cervical cancer with respect to PD-L1 status. MethodsA total of 140 patients were included in this multicentric ambidirectional study. Immunohistochemical analysis for PD-L1 was performed on paraffin-embedded, formalin-fixed sections using 22C3 PharmDx assay (Dako) and tumour proportion score was calculated. PD-L1 expression status concerning the distribution of clinicopathological features was further studied. ResultsThis study included 133 cases of cervical carcinoma and 7 cases of cervical intraepithelial neoplasia (140 cases), with a prevalence of PDL1 positivity in 31.4% of cases with 15% (n = 21) tumours high positive, 16.4% (n = 23) low positive and 68.6% (n = 96) negative for PD-L1. It was observed that all cases with PD-L1 positivity were characterized as squamous cell carcinoma. The mean age of subjects was 56.74 ± 11.52 years. PD-L1 high positivity was observed in 26.7% of individuals in the age group >70 years, 21.7% of grade 3 tumours, 11.4% of tumours exceeding 4 cm in size, and 33.3% of cases showing recurrence. PD-L1 immunoexpression did not demonstrate a significant association with the patient's age, tumour grade and stage, as well as recurrence. ConclusionIt is envisaged that anti-PD-L1 immunotherapy could show promising antitumour activity and early survival rates among patients with cervical squamous cell carcinoma.

The Association of Programmed Death Ligand 1 (PD-L1) and Cluster of Differentiation 95 Ligand (CD95L) Immunoexpression with Chemotherapy Response in Classical Hodgkin Lymphoma

Background: Programmed Death Ligand (PD-L1) and Cluster of Differentiation 95 (CD95L) are influenced by oncogenes and function in the anti-apoptosis process which is thought to play a role in chemotherapy resistance. This study aimed to analyze the association of PD-L1 and CD95L immunoexpression with chemotherapy response in Classical Hodgkin Lymphoma (CHL).Method: This study involved 40 cases of histopathologically diagnosed CHL treated with doxorubicin, bleomycin, vinblastine, and dacarbazine (ABVD) chemotherapy. PD-L1 and CD95L immunohistochemical staining were performed in selected paraffin-embedded tissue blocks of all cases. The chemotherapy response status of the patients was taken from the medical recordResults: High PDL-1 immunoexpression was evident in 19 (47.5%) cases while positive CD95L immunoexpression was found in 14 (35%) CHL cases. High PD-L1 immunoexpression was significantly associated with the Non-Responsive (NR) group (78.9%) with p-value = 0.0001. Positive CD95L immunoexpression was greater in the NR group (71.4%) with p-value = 0.37.Conclusion: : High PD-L1 immunoexpression indicated an unfavorable response to ABVD chemotherapy in CHL. CD95L immunoexpression was not associated with ABVD chemotherapy response in CHL.

PD-L1 expression in muscle invasive urothelial carcinoma: Comparison of SP142 and SP263 assay.

High-grade urothelial carcinoma has a different molecular pathway than superficial low grade urothelial carcinoma, and is characterized by genomic instability. The high tumor mutation burden leads to neoantigen formation, evoking an immune response. The immune response has been keenly studied in last two decades and programmed death ligand-1 (PDL-1) has emerged as acceptable immunohistochemical marker for assessment of response to therapy, prognostication and patient selection for immunotherapy. The targeting of PD-1 and PDL-1 by checkpoint inhibitors (CPIs) is an attractive strategy to unblock the inhibitor and induce cytotoxic cell death. However, the presence of complementary and companion diagnostic testing with multiple PDL-1 assays and platforms for various CPIs make a diagnostic quagmire. Thus, it is the need of hour to harmonize these assays. In this undertaken study we evaluated the concordance in PD-L1 expression between the two PD-L1 clones: SP263 and SP142, in treatment naïve muscle invasive bladder cancer (MIBC). We evaluated Ventana PD-L1 "SP263 and SP142" qualitative immunohistochemical assay using rabbit monoclonal anti-PD-L1 clones in evaluation of PDL-1 immunoexpression on Ventana autostainer platform. The study includes 30 muscle invasive urothelial carcinomas, with 10 of 30 having nodal metastasis. SP263 assay was statistically more sensitive than SP142 for tumor cell (TC) scoring (P = 0.0009), whereas SP142 was more sensitive for immune cell (IC) scoring (P = 0.0067). There was no statistical significant discordance for TC or IC scoring between primary tumor and metastatic lymph node. PD-L1 testing status can be done on both primary tumor and metastatic site, however in metachronous metastatic setting, testing on recent metastatic site should be preferred. The harmonization of immunoexpression between 2 PD-L1 clones could not be achieved.

PD-L1 expression in breast invasive ductal carcinoma with incomplete pathological response to neoadjuvant chemotherapy.

Objectives:To investigate the expression of programmed death-ligand 1 (PD-L1) in breast cancer in association with incomplete pathological response (PR) to neoadjuvant chemotherapy (NAC).MethodsPD-L1 expression was evaluated using immunohistochemistry in post-operative, post-NAC samples of 60 patients (n = 60) diagnosed with breast invasive ductal carcinoma with incomplete PR to NAC, including 31 matched pre-NAC and post-NAC samples (n = 31). PD-L1 protein expression was assessed using three scoring approaches, including the tumor proportion score (TPS), the immune cell score (ICS), and the combined tumor and immune cell score (combined positive score, CPS) with a 1% cut-off.ResultsIn the post-operative, post-NAC samples (n = 60), positive expression rate of PD-L1 was observed in 18.3% (11/60) of cases by TPS, 31.7% (19/60) by ICS, and 25% (15/60) by CPS. In matched samples, positive expression rate of PD-L1 was observed in 19.3% (6/31) of patients by TPS, 51.6% (16/31) by ICS, and 19.3% (6/31) by CPS in pre-NAC specimens, while it was observed in 22.6% (7/31) of matched post-NAC samples by TPS, 22.6% (7/31) by ICS, and 19.3% (6/31) by CPS. In the matched samples, there was a significant decrease in PD-L1 immunoexpression using ICS in post-NAC specimens (McNemar’s, p = 0.020), while no significant differences were found using TPS and CPS between pre- and post-NAC samples (p = 1.000, p = 0.617; respectively). PD-L1 immunoexpression determined by TPS or CPS was only significantly associated with ER status (p = 0.022, p = 0.021; respectively), but not with other clinicopathological variables. We could not establish a correlation between PD-L1 expression and the overall survival rate (p > 0.05). There were no significant differences in the tumor infiltrating lymphocytes count between the paired pre- and post-NAC samples (t = 0.581, p = 0.563 or Wilcoxon’s Signed Rank test; z = -0.625, p = 0.529).ConclusionOur findings indicate that PD-L1 protein expression in infiltrating immune cells was significantly reduced in breast tumors that developed incomplete PR following the exposure to NAC.

Assessment of programmed death-ligand 1 receptor immunohistochemical expression and its association with tumor-infiltrating lymphocytes and p53 status in triple-negative breast cancer.

Breast cancer (BC) is the second most frequent type of cancer for both sexes combined, after lung cancer. Triple-negative BC (TNBC) molecular subtype is characterized by lack of estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor 2 (HER2) immunoexpression or amplification and represent 10–20% of all BC cases. The issue of the present study was to analyze the associations between programmed death-ligand 1 (PD-L1) immunoexpression and distribution of stromal tumor-infiltrating lymphocytes (stTILs) combined with clinico-morphological features of patients with TNBC. Secondly, our research evaluated PD-L1 immunoexpression as a prognostic factor and its correlation with p53 immunoexpression. Thirty cases with primary TNBC without prior neoadjuvant therapy were included in this research. stTILs were identified in all cases, most of them with low distribution (66.7%). A positive immunoreaction for PD-L1 was observed in 40% of cases. The PD-L1 immunoexpression was statistically significant associated with age, pathological tumor size, lymphovascular invasion, stTILs level, the presence of cluster of differentiation 8-positive (CD8+) TILs and p53 immunoexpression. In the present study, a positive PD-L1 immunoexpression was associated with a worse distant metastasis free survival (DMFS). We also found not only that high stTILs level were associated with a better DMFS but also that there was a statistically significant association between stTILs level and PD-L1 immunoexpression. Our results bring new insights to the fine connections between tumor microenvironment and molecular changes of TNBC. It helps us to better understand these aggressive tumors to identify the more useful biomarkers for predicting the response to adjuvant therapy and can represent a method for selecting the most suitable patients for immunotherapy.

High Immunoexpression of COX-2 as a Metastatic Risk Factor in ccRCC without PD-L1 Involvement.

IntroductionClear cell renal cell carcinoma (ccRCC) is the most lethal type of malignancy of the urinary tract system as it is resistant to chemotherapy and radiation and has a survival rate of less than 5% in cases of metastasis. Inflammation plays an essential role in the metastasis of ccRCC. Cyclooxygenase-2 (COX-2) is an inflammatory protein that affects the processes of carcinogenesis, invasion, migration, metastasis, and angiogenesis. COX-2 can modulate programmed death ligand-1 (PD-L1) expression and play a role in immune evasion, meaning that tumor cells are able to escape the body’s immune response and more easily metastasize.PurposeThis study aims to determine the role of COX-2 and PD-L1 in the occurrence of ccRCC metastases.Materials and MethodsThis study is an observational analytical study, which employed a cross-sectional approach to examine the paraffin block samples of 40 ccRCC cases from Dr. Hasan Sadikin Hospital Bandung, Indonesia, between 2014 and 2021. Immunoexpression was measured using immunohistochemical staining for COX-2 in tumor cells and for PD-L1 in immune cells. PD-L1 calculation was measured using Qupath 0.2.3. digital software. Metastatic data were obtained using radiological imaging and pathological examinations. Meanwhile, the data were analyzed using the chi-square test for COX-2 and Fischer’s exact test for PD-L1.ResultsThe research results revealed a significant association between COX-2 and the occurrence of metastases in ccRCC (p=0.001) with a prevalence odds ratio of 10.28. Positive PD-L1 immunoexpression of the immune cells (≥1%) was found in 14% (3/21) of the metastatic group and 5% (1/19) of the non-metastatic group (p=0.607). There was no association between COX-2 and PD-L1 immunoexpression (p=0.278).ConclusionThis study shows that metastases in ccRCC patients are ten times as likely to be associated with high COX-2 immunoexpression than low COX-2 immunoexpression. COX-2 plays a role in the process of ccRCC metastasis without PD-L1 involvement.

Expression of programmed death ligand 1 (PD-L1) in urothelial bladder carcinoma (immunohistochemical and histopathological study)

The aim of this work is to evaluate the immunohistochemical expression of PD-L1 in tumor cells of urothelial bladder carcinoma. PD-L1 immunoexpression was assessed on 20 cases of radical cystectomy specimens using monoclonal rabbit anti- PD-L1 antibody. Extent of membranous PD-L1 expression was assigned in each case. Tumor cells showing > 5% expression were considered positive. PD-L1was seen in 6 (30%) cases [1 case score +2 and 5 cases score +3], while 14(70%) cases were negative [7 cases score 0 and 7 cases score +1]. PD-L1 expression in tumor cells was insignificantly correlated with different available clinicopathological parameters such as sex, pathological stage, associatedbilharzial infestation, necrosis, perineural invasion and associated tumor infiltrating mononuclear cells (TIMCs), although PD-L1 positivity tend to predominate in advanced pathological stage of tumor (T3 and T4). These findings may have clinical implications for the management of patients with PD-L1 positive urothelial bladder carcinoma.

Programmed Death Ligand-1 (PD-L1) expression is up-regulated and related to the pattern of invasion in FIGO Stage I vulvar squamous cell carcinomas

The immune checkpoint protein programmed death ligand-1 (PD-L1) is expressed in different types of cancer and is a potential prognostic factor as well as therapeutic target. This study evaluated PD-L1 expression in the neoplastic progression of vulvar epithelia with respect to the pattern of infiltration in FIGO stages I keratinizing squamous cell carcinomas (SCC). Normal squamous vulvar epithelia (n=20), usual type vulvar intraepithelial neoplasia (uVIN, n=23), differentiated VIN (dVIN, n=21) and FIGO stage I SCC (n=35) were immunostained for PD-L1. In SCC a cohesive growth with well-delineated borders was considered as pushing, dissociative growth in small groups or single cells was defined as diffuse pattern of infiltration. Immunostaining was done with a monoclonal anti PD-L1 antibody (clone SP263, Ventana) and scored to determine up-regulation and overexpression (score 0/1+, 0-5% immunoreactive cells; score 2+, >5 to 50% immunoreactive cells; score 3+, >50% immunoreactive cells). PD-L1 immunoexpression was comparable in normal epithelia and VINs (score 0/1+, n=59; score 2+, n=5, in VINs only; score 3+, n=0), was significantly increased (P<0.0001) in SCC (score 0/1+, n=13; score 2+, n=16; score 3+, n=6), and was related to a diffuse pattern of infiltration (P<0.0001). Staining was accentuated at the invasive margins of SCC frequently. PD-L1 expression is up-regulated in the neoplastic cells of vulvar low stage SCC, related to the development of an invasive phenotype reflecting the initiation of cancer immunoediting, and to an aggressive diffuse type of stromal invasion.

Analysis of Mutant Isocitrate Dehydrogenase 1 Immunoexpression, Ki-67 and Programmed Death Ligand 1 in Diffuse Astrocytic Tumours : Study of Single Center in Bandung, Indonesia.

ObjectiveDiffuse astrocytic tumour (DAT) is a diffuse infiltrative astrocytoma tumour accompanied by molecular parameters such as the presence or absence of isocitrate dehydrogenase (IDH) gene mutations. Ki-67 is a marker for DAT proliferation, while programmed death ligand 1 (PD-L1) indicates an immune evasion mechanism. This study aimed to analyze the correlation among mutant IDH1 R132H, Ki-67, and PD-L1 immunoexpression in the DAT. MethodsA cross-sectional study was carried out on 30 paraffin blocks of DAT cases. Paraffin block samples consist of grade II (n=14), grade III (n=8), and grade IV (n=8). In this study, the immunohistochemistry-staining of mutant IDH1 R132H, Ki-67, and PD-L1 were carried out to determine the frequency of DAT with IDH1 mutations. ResultsOur study shown the frequency of IDH1 mutations in grade II 50.0% (7/14), grade III 37.5% (3/8), and grade IV 12.5% (1/8). Our study also showed a difference in Ki-67 and PD-L1 expression between each the degree of DAT histopathology (p=0.0001 and p=0.002, respectively). There was an association between both mutant IDH1 R132H, and Ki-67 with PD-L1 expression in DAT (p=0.0087 and p=0.0049, respectively). ConclusionDAT with the mutant IDH1 is frequently observed in grade II and small number of grade III. The expression of wild type IDH1, Ki-67, and PD-L1 were found to be higher in high grade DAT (grade III and grade IV). There is a correlation between each of mutant IDH1 status and Ki-67 with PD-L1 expression in DAT.

Association of Programmed Death Ligand 1 and C-X-C Chemokine Receptor Type 4 Immunoexpression with Pelvic Lymph Node Metastasis in Cervical Squamous Cell Carcinoma

BACKGROUND: Squamous cell carcinoma (SCC) is the most common type of cervical cancer. Pelvic lymph node metastasis in cervical SCC is common. Programmed death ligand 1 (PD-L1) on tumor cells has been reported to impede anti-tumor immunity, resulting in immune evasion. C-X-C chemokine receptor type 4 (CXCR4) plays an important role in proliferation, survival, and migration (chemotaxis) of tumor cells.&#x0D; AIM: This study aimed to analyze the association of PD-L1 and CXCR4 immunoexpression with pelvic lymph node metastasis in cervical SCC.&#x0D; MATERIALS AND METHODS: Forty cases of cervical SCC in the Department of Anatomical Pathology, Faculty of Medicine, Padjadjaran University, Dr. Hasan Sadikin Hospital, Bandung, during 2013–2018 were collected and divided into two groups; (1) cervical SCC metastasize to pelvic lymph node and (2) cervical SCC non-metastasize to pelvic lymph node, of 20 cases, respectively. The expression of PD-L1 and CXCR4 was detected using immunohistochemistry.&#x0D; RESULTS: High immunoexpression of PD-L1 and CXCR4 in cervical SCC showed significant association with pelvic lymph node metastasis (p &lt; 0.05). The stepwise logistic regression analysis revealed that both PD-L1 and CXCR4 immunoexpression influenced pelvic lymph node metastasis simultaneously.&#x0D; CONCLUSION: It could be concluded that the higher PD-L1 and CXCR4 immunoexpression showed the higher ability of tumor cells to metastasize to the pelvic lymph node.

Programmed Death-Ligand 1 (PD-L1) Is a Potential Biomarker of Disease-Free Survival in Papillary Thyroid Carcinoma: a Systematic Review and Meta-Analysis of PD-L1 Immunoexpression in Follicular Epithelial Derived Thyroid Carcinoma.

The expression of programmed death-ligand 1 (PD-L1) is an established prerequisite for the administration of checkpoint inhibitor therapy and is of prognostic value in several cancer types. Data concerning the potential effect of PD-L1 on the prognosis of thyroid carcinoma are limited. Therefore, this study aimed to provide a systematic review of the published data on this topic. The literature was reviewed to gather and quantify evidence on the prognostic role of PD-L1 in follicular epithelial derived thyroid carcinomas and determine its association with clinicopathological parameters. A meta-analysis was performed using the DerSimonian-Laird random-effects model. The quality of studies was evaluated with the Newcastle-Ottawa Scale and a modified GRADE approach used to rate the quality of evidence. Out of 445 papers, 18 were included and 15 provided adequate data for meta-analysis. The quality of evidence ranged from low to high. PD-L1 expression was significantly associated with a reduced disease-free survival (DFS) (RR 1.63, CI 1.04-2.56, p= 0.03, I2 68%, τ2 0.19 and HR 1.90, CI 1.33-2.70, p< 0.001, I2 0%, τ2 0.00); however, no association was found with the overall survival (OS). Furthermore, a significant association was found with respect to underlying chronic lymphocytic thyroiditis and BRAFV600E mutation status in papillary thyroid carcinomas. In the subgroup analysis, the association of PD-L1 and DFS remained strong in papillary thyroid carcinoma when compared with dedifferentiated thyroid carcinomas (anaplastic and poorly differentiated thyroid carcinomas) that failed to demonstrate a significant association with respect to PD-L1. These findings underscore the role of PD-L1 immunohistochemistry as a potential prognostic biomarker of disease recurrence in patients with papillary thyroid carcinoma.

RAD51Bme as predictive biomarker for PD-1 blockade response in non-small cell lung cancer.

e15235 Background: Lung cancer (LC) cells frequently express high levels of programmed death-ligand 1 (PD-L1). Although these levels grossly correlate with likelihood of response to specific checkpoint inhibitors, prediction of response is rather imperfect and, thus, more accurate predictive biomarkers are mandatory. We examined the methylation profile of RAD51B, a DNA-repair gene, as candidate predictive biomarker for efficacy of anti-PD-1 therapy in patients with non-small cell lung cancer (NSCLC), correlating with patients’ outcome. Methods: PD-L1 immunoexpression and RAD51Bme levels were analysed in samples of NSCLC obtained from patients not treated with anti-PD-1 blockade (testing cohort) and patients treated with anti-PD-1 (validation cohort). Results: Of a total of 127 patients assessed, 58.3% depicted positivity for PD-L1 (PD-L1+). RAD51Bme levels significantly associated with PD-L1 immunoexpression. Patients with clinical benefit from immunotherapy disclosed higher RAD51Bme levels (p = 0.04) and significantly higher median progression free survival (PFS) (p = 0.02). PD-L1+ was also associated with longer overall survival (p = 0.03). Conclusions: We demonstrated that RAD51Bme levels might be combined with validated predictive biomarker PD-L1 immunostaining to select patients who will most likely experience clinical benefit from PD-1 blockade. The predictive value of RAD51Bme should be confirmed in prospective studies.

RAD51Bme Levels as a Potential Predictive Biomarker for PD-1 Blockade Response in Non-Small Cell Lung Cancer.

Lung cancer (LC) cells frequently express high levels of programmed death-ligand 1 (PD-L1). Although these levels grossly correlate with the likelihood of response to specific checkpoint inhibitors, the response prediction is rather imperfect, and more accurate predictive biomarkers are mandatory. We examined the methylation profile of RAD51B (RAD51Bme) as a candidate predictive biomarker for anti-PD-1 therapy efficacy in non-small cell lung cancer (NSCLC), correlating with patients’ outcome. PD-L1 immunoexpression and RAD51Bme levels were analysed in NSCLC samples obtained from patients not treated with anti-PD-1 (Untreated Cohort (#1)) and patients treated with PD-1 blockade (Treated Cohort (#2)). Of a total of 127 patients assessed, 58.3% depicted PD-L1 positivity (PD-L1+). RAD51Bme levels were significantly associated with PD-L1 immunoexpression. Patients with PD-1 blockade clinical benefit disclosed higher RAD51Bme levels (p = 0.0390) and significantly lower risk of disease progression (HR 0.37; 95% CI: 0.15–0.88; p = 0.025). Combining RAD51Bme+ with PD-L1+ improved the sensitivity of the test to predict immunotherapy response. PD-L1+ was also associated with lower risk of death (HR 0.35; 95% CI: 0.15–0.81; p = 0.014). Thus, RAD51Bme levels might be combined with validated predictive biomarker PD-L1 immunostaining to select patients who will most likely experience clinical benefit from PD-1 blockade. The predictive value of RAD51Bme should be confirmed in prospective studies.

From This Month's Histopathology

From This Month's Histopathology

PD-L1 immuno-expression assay in thymomas: Study of 84 cases and review of literature

Programmed death ligand 1 (PD-L1), an immune check point inhibitor, is known to be expressed in several malignancies and is being considered as a prognostic factor and a potential immunotherapeutic target. The aim of this study was to characterize PD-L1 expression in thymomas and to determine correlation with clinicopathological features and previously published studies in the literature. Tissue microarrays were prepared from selected blocks of thymomas and immunohistochemistry (IHC) for PD-L1 was performed. Cases were considered as PD-L1 positive or negative depending on whether the percentage of stained thymic epithelial cells were <25 or >25%. Results were compared clinically and with previously published studies using Google and Pubmed search engines. Of 84 cases of thymoma, 69 (82.1%) revealed PD-L1 positivity in >25% cells. 94.23% of type B thymoma subtypes (B1/B2/B3) were PD-L1 positive (P < 0.001). There was no correlation of PD-L1 with age, gender, myasthenia gravis, the tumor size or stage of disease. Nine studies were available in the literature; most of which showed PD-L1 expression in higher stage and B subtype however percentage positivity varied from 53.7% to over 90%. PD-L1 expression is frequent in type B (B1/B2/B3) thymomas. It can be easily evaluated by IHC even on small biopsies in unresectable cases, thereby enabling improved clinical evaluation as well as prognostic stratification of patients. It will serve as a potential indicator for benefit from anti-PD-L1 antibody immunotherapy in thymomas.

Expression of programmed death-ligand 1 and hypoxia-inducible factor-1α proteins in endometrial carcinoma.

Programmed death-ligand 1 (PD-L1) and hypoxia-inducible factor-1α (HIF-1α) proteins mediate major alterations of tumor microenvironment including generation of immunosuppressive microenvironment and tumor hypoxia, respectively. These alterations play a crucial role in carcinogenesis and tumor progression. The present study was designed to investigate the correlation between the expression of PD-L1 and HIF-1α proteins and the clinicopathologic variables in endometrial carcinoma. Tumor tissue sections from 95 endometrial carcinomas were evaluated for PD-L1 and HIF-1α immunohistochemical protein expression. The statistical analyses were performed using Chi-square and Fisher's exact tests when appropriate. Two-sided P < 0.05 was considered statistically significant. PD-L1 and HIF-1α expression were detected in 48.4% and 68.4% of endometrial carcinomas, respectively. PD-L1 expression was significantly associated with lymph node metastasis (P = 0.027). HIF-1α expression was significantly associated with tumor grade, depth of myometrial invasion, and lymph node metastasis (P = 0.014, 0.012, and 0.046, respectively). A significant positive correlation was detected between PD-L1 and HIF-1α immunoexpression (P = 0.015). PD-L1 and HIF-1α proteins are promising potential prognostic biomarkers in endometrial carcinomas since their overexpression is associated with clinicopathologic variables of advanced disease. A potential role of HIF-1α in upregulation of PD-L1 expression is suggested based on the finding of positive correlation between PD-L1 and HIF-1α expression in endometrial carcinoma. These findings point to a potential role of biomarkers inhibitors in controlling endometrial cancer progression.

Assessment of Tumoral PD-L1 Expression and Intratumoral CD8+ T Cells in Urothelial Carcinoma

To evaluate programmed death ligand 1 (PD-L1) expression in urothelial carcinoma of the bladder in relationship with tumor-infiltrating CD8+ T cells. Tissue microarrays were prepared from 56 cystectomy specimens performed at our hospital (1994-2002). PD-L1 immunoexpression was assessed using the murine antihuman PD-L1 monoclonal antibody 5H1. Extent of membranous PD-L1 expression was assigned in each spot. Spots showing ≥5% expression were considered positive. Average PD-L1 expression per tumor was also calculated (5% positivity cutoff). "High CD8 density" was defined as the presence of ≥60 CD8+ intraepithelial lymphocytes per high power field in a given spot. A tumor was considered high density if ≥50% of its spots were of high density. PD-L1 expression was positive in approximately 20% of tumors. None of the benign urothelium spots expressed PD-L1. High CD8 density was observed in approximately 20% of cases. CD8 density did not correlate with PD-L1 expression. Overall survival (OS) and disease-specific survival (DSS) rates were 14% and 28%, respectively (median follow-up, 31.5 months). PD-L1 expression was associated with age at cystectomy (P = .01). Remaining clinicopathologic parameters were not associated with PD-L1 expression or CD8 density. High CD8 density was associated with favorable OS (P = .02) and DSS (P = .02). The same was true when CD8 density was adjusted for demographic and clinicopathologic parameters. There was no correlation between PD-L1 expression and outcome. High intratumoral CD8+ T cell density is associated with better OS and DSS in invasive urothelial carcinoma of the bladder. We found no correlation between PD-L1 expression and outcome.