Efficacy comparison of fruquintinib,regorafenib monotherapy or plus programmed death-1 inhibitors for microsatellite stable metastatic colorectal cancer

BACKGROUND Regorafenib(R)and fruquintinib(F)are the standard third-line regimens for colorectal cancer(CRC)according to the National Comprehensive Cancer Network guidelines,but both have limited efficacy.Several phase 2 trials have indicated that R or F combined with immune checkpoint inhibitors can reverse immunosuppression and achieve promising efficacy for microsatellite stable or proficient mismatch repair(MSS/pMMR)CRC.Due to the lack of studies comparing the efficacy between F,R,F plus programmed death-1(PD-1)inhibitor,and R plus PD-1 inhibitors(RP),it is still unclear whether the combination therapy is more effective than monotherapy.AIM To provide critical evidence for selecting the appropriate drugs for MSS/pMMR metastatic CRC(mCRC)patients in clinical practice.METHODS A total of 2639 CRC patients were enrolled from January 2018 to September 2022 in our hospital,and 313 MSS/pMMR mCRC patients were finally included.RESULTS A total of 313 eligible patients were divided into F(n=70),R(n=67),F plus PD-1 inhibitor(FP)(n=95)and RP(n=81)groups.The key clinical characteristics were well balanced among the groups.The median progression-free survival(PFS)of the F,R,FP,and RP groups was 3.5 months,3.6 months,4.9 months,and 3.0 months,respectively.The median overall survival(OS)was 14.6 months,15.7 months,16.7 months,and 14.1 months.The FP regimen had an improved disease control rate(DCR)(P=0.044)and 6-month PFS(P=0.014)and exhibited a better trend in PFS(P=0.057)compared with F,and it was also significantly better in PFS than RP(P=0.030).RP did not confer a significant survival benefit;instead,the R group had a trend toward greater benefit with OS(P=0.080)compared with RP.No significant differences were observed between the R and F groups in PFS or OS(P>0.05).CONCLUSION FP is superior to F in achieving 6-month PFS and DCR,while RP is not better than R.FP has an improved PFS and 6-month PFS compared with RP,but F and R had similar clinical efficacy.Therefore,FP may be a highly promising strategy in the treatment of MSS/pMMR mCRC.

C-reactive protein to albumin ratio predict responses to programmed cell death-1 inhibitors in hepatocellular carcinoma patients

BACKGROUND Over the years,programmed cell death-1(PD-1)inhibitors have been routinely used for hepatocellular carcinoma(HCC)treatment and yielded improved survival outcomes.Nonetheless,significant heterogeneity surrounds the outcomes of most studies.Therefore,it is critical to search for biomarkers that predict the efficacy of PD-1 inhibitors in patients with HCC.AIM To investigate the role of the C-reactive protein to albumin ratio(CAR)in evaluating the efficacy of PD-1 inhibitors for HCC.METHODS The clinical data of 160 patients with HCC treated with PD-1 inhibitors from January 2018 to November 2022 at the First Affiliated Hospital of Guangxi Medical University were retrospectively analyzed.RESULTS The optimal cut-off value for CAR based on progression-free survival(PFS)was determined to be 1.20 using x-tile software.Cox proportional risk model was used to determine the factors affecting prognosis.Eastern Cooperative Oncology Group performance status[hazard ratio(HR)=1.754,95%confidence interval(95%CI)=1.045-2.944,P=0.033],CAR(HR=2.118,95%CI=1.057-4.243,P=0.034)and tumor number(HR=2.932,95%CI=1.246-6.897,P=0.014)were independent prognostic factors for overall survival.CAR(HR=2.730,95%CI=1.502-4.961,P=0.001),tumor number(HR=1.584,95%CI=1.003-2.500,P=0.048)and neutrophil to lymphocyte ratio(HR=1.120,95%CI=1.022-1.228,P=0.015)were independent prognostic factors for PFS.Two nomograms were constructed based on independent prognostic factors.The C-index index and calibration plots confirmed that the nomogram is a reliable risk prediction tool.The ROC curve and decision curve analysis confirmed that the nomogram has a good predictive effect as well as a net clinical benefit.CONCLUSION Overall,we reveal that the CAR is a potential predictor of short-and long-term prognosis in patients with HCC treated with PD-1 inhibitors.If further verified,CAR-based nomogram may increase the number of markers that predict individualized prognosis.

Over-expression of programmed death-ligand 1 and programmed death-1 on antigen-presenting cells as a predictor of organ dysfunction and mortality during early sepsis: a prospective cohort study

BACKGROUND:This study aimed to explore the changes of programmed death-ligand 1(PDL1)and programmed death-1(PD-1)expression on antigen-presenting cells(APCs)and evaluate their association with organ failure and mortality during early sepsis.METHODS:In total,40 healthy controls and 198 patients with sepsis were included in this study.Peripheral blood was collected within the first 24 h after the diagnosis of sepsis.The expression of PDL1 and PD-1 was determined on APCs,such as B cells,monocytes,and dendritic cells(DCs),by flow cytometry.Cytokines in plasma,such as interferon-γ(IFN-γ),tumor necrosis factor-α(TNF-α),interleukin-4(IL-4),IL-6,IL-10,and IL-17A were determined by Luminex assay.RESULTS:PD-1 expression decreased significantly on B cells,monocytes,myeloid DCs(mDCs),and plasmacytoid DCs(pDCs)as the severity of sepsis increased.PD-1 expression was also markedly decreased in non-survivors compared with survivors.In contrast,PD-L1 expression was markedly higher on mDCs,pDCs,and monocytes in patients with sepsis than in healthy controls and in non-survivors than in survivors.The PD-L1 expression on APCs(monocytes and DCs)was weakly related to organ dysfunction and infl ammation.The area under the receiver operating characteristic curve(AUC)of the PD-1 percentage of monocytes(monocyte PD-1%)+APACHE II model(0.823)and monocyte PD-1%+SOFA model(0.816)had higher prognostic value than other parameters alone.Monocyte PD-1%was an independent risk factor for 28-day mortality.CONCLUSION:The severity of sepsis was correlated with PD-L1 or PD-1 over-expression on APCs.PD-L1 in monocytes and DCs was weakly correlated with infl ammation and organ dysfunction during early sepsis.The combination of SOFA or APACHE II scores with monocyte PD-1%could improve the prediction ability for mortality.

Advances on biological evaluation methods of programmed cell death protein-1/ligand-1 inhibitors

Immuno-oncology represents a groundbreaking and well-established field within cancer treatment.Among the various immuno-oncology targets,the exploration of programmed cell death-1/ligand-1 for drug discovery has proven to be one of the most successful endeavors.Remarkably,it took nearly 30 years from the initial target identification to the clinical approval of monoclonal antibodies.Providing suitable and reliable bioassays for drug candidate evaluation is of paramount importance throughout the early stages of drug discovery,from lead compound identification to in vivo efficacy testing.This assay review aims to shed light on diverse assays reported in the literature for testing antagonism activity and efficacy of programmed cell death-1/ligand-1 inhibitors.Each of these assays possesses inherent advantages and can be applied in different research scenarios.The insights presented in this summary can serve as a valuable resource for scientists in this field,aiding in the selection of appropriate assays for their specific investigations.

Programmed death-1 expression is associated with the disease status in hepatitis B virus infection

AIM： TO define the potential role of programmed death-i/programmed death-ligand （PD-1/PD-L） pathway in different hepatitis B virus （HBV） infection disease status; we examined the expression of PD-1 on antigen specific CD8＋T cells in peripheral blood of patients with chronic hepatitis B （CriB） and acute exacerbation of hepatitis B （AEHB） infection. METHODS： The PD-1 level on CD8＋ T lymphocytes and the number of HBV specific CD8＋ T lymphocytes in patients and healthy controls （HCs） were analyzed by staining with pentameric peptide-human leukocyte antigen2 （HLA2） complexes combined with flow cytometry. Real-time quantitative polymerase chain reaction （PCR） was used to measure the serum HBV- DNA levels. RESULTS： The level of PD-1 expression on total CD8＋ T cells in CHB patients （13.86% ± 3.38%） was significantly higher than that in AEHB patients （6.80%± 2.19%, P 〈 0.01） and healthy individuals （4.63% ± 1.23%, P 〈 0.01）. Compared to AEHB patients （0.81% ± 0.73%）, lower frequency of HBV-specific CD8＋ T cells was detected in chronic hepatitis B patients （0.37% ± 0.43%, P 〈 0.05）. There was an inverse correlation between the strength of HBV-specific CD8＋ T-cell response and the level of PD-1 expression. Besides, there was a significant positive correlation between HBV viral load and the percentage of PD-1 expression on CD8＋ T cells in CriB and AEHB subjects （R = 0.541, P 〈 0.01）. However, PD-1 expression was not associated with disease flare-ups as indicated by alanine aminotransferase （ALT） levels （R = 0.066, P 〉 0.05）. CONCLUSION： Our results confirm previous reports that HBV specific CD8＋T-cell response in the peripheral blood is more intense in patients with AEHB than in chronic hepatitis B wlth persistent viral infection. Moreover, there is a negative correlation between the level of PD-1 and the intensity of virus specific CD8＋ T cell response.

Prognostic value of programmed death.1, programmed death-ligand 1, programmed death-ligand 2 expression, and CD8(+) T cell density in primary tumors and metastatic lymph nodes from patients with stage T1.4N+M0 gastric adenocarcinoma

Background: Anti-programmed death-1/programmed death-ligand 1(PD-1/PD-L1) immunotherapy has been proved to be effective on gastric cancer in ongoing clinical trials. However, the value of PD-L1 in predicting responses of patients with gastric cancer to anti-PD-1/PD-L1 immunotherapy is controversial. Some studies suggested that intra-and inter-tumoral heterogeneity of PD-L1 expression might explain the controversy.This study aimed to analyze the expression of PD-L1, PD-L2, and PD-1 as well as CD8(+) T-cell density in primary tumors and lymph nodes from patients with stage T1-4 N+M0 gastric adenocarcinoma to explore the heterogeneity of PD-1 signaling pathway molecules.Methods: In primary tumors and metastatic as well as non-metastatic lymph nodes from patients with stage T1-4 N+M0 gastric adenocarcinoma, we detected PD-L1 and PD-L2 expression with immunohistochemistry. CD8(+)T-cell density in primary tumors and PD-1 expression on CD8(+)T cells were detected with immunofluorescence. Univariate analysis was used to determine the prognostic values of them. Cox proportional hazard regression model was used to identify independent risk factors that affect patients' overall survival and disease-free survival.Results: Among 119 eligible patients who had undergone surgical resection, the positive rate of PD-L1 was higher in metastatic lymph nodes than in primary tumors(45.4% vs. 38.7%, P = 0.005); the positive rate of PD-1 on CD8(+)T cells was significantly higher in primary tumors and metastatic lymph nodes than in tumor-free lymph nodes(both P < 0.001). The intensity of PD-1 expression on CD8(+) T cells in primary tumors and in metastatic lymph nodes were stronger than that in tumor-free lymph nodes from the same patient. Beside, the positive rate of PD-L2 did not show any differences between primary tumors and metastatic lymph nodes. In multivariate analysis, PD-L1 expression,PD-L2 expression, a low density of CD8(+) T cells in primary tumors, and PD-1 expression on CD8(+) T cells in primary tumors were associated with poor prognosis.Conclusion: The expression of PD-L1 is heterogeneous in primary tumors and in metastatic lymph nodes from patients with stageT1-4 N+M0 gastric adenocarcinoma, which might explain the inconsistent results in assessing the prognostic value of PD-L1 expression in previous studies.

Programmed cell death-1 inhibitor-related sclerosing cholangitis:A systematic review

BACKGROUND Programmed cell death-1(PD-1)inhibitor has been indicated for many types of malignancies.However,these inhibitors also cause immune-related adverse events.Hepatobiliary disorder is a phenotype of immune-related adverse event affecting 0%–4.5%of patients treated with PD-1 inhibitors.Recent studies have reported PD-1 inhibitor-related sclerosing cholangitis(SC);however,the associated clinical and pathological features are unclear.AIM To evaluate the clinical and pathological features of PD-1 inhibitor-related SC through a systematic review of the literature.METHODS The review,conducted using electronic databases in PubMed,was restricted to the period from January 2014 to September 2019 and focused on case reports/series on PD-1 inhibitor-related SC published in English.We scanned the references of the selected literature to identify any further relevant studies.Six cases previously studied by us,including three that have not yet been published,were included in this review.RESULTS Thirty-one PD-1 inhibitor-related SC cases were evaluated.Median age of patients was 67 years(range,43–89),with a male to female ratio of 21:10.The main disease requiring PD-1 inhibitor treatment was non-small cell lung cancer.Agents that caused PD-1 inhibitor-related SC were nivolumab(19 cases),pembrolizumab(10 cases),avelumab(1 case),and durvalumab(1 case).The median number of cycles until PD-1 inhibitor-related SC onset was 5.5(range,1–27).Abdominal pain or discomfort(35.5%,11/31)was the most frequent symptom.Blood serum tests identified liver dysfunction with a notable increase in biliary tract enzymes relative to hepatic enzymes,and a normal level of serum immunoglobulin G4.Biliary dilation without obstruction(76.9%,20/26),diffuse hypertrophy of the extrahepatic biliary tract(90.5%,19/21),and multiple strictures of the intrahepatic biliary tract(30.4%,7/23)were noted.In 11/23(47.8%)cases,pathological examination indicated that CD8+T cells were the dominant inflammatory cells in the bile duct or peribiliary tract.Although corticosteroids were mainly used for PD inhibitor-related SC treatment,the response rate was 11.5%(3/26).CONCLUSION Some clinical and pathological features of PD-1 inhibitor-related SC were revealed.To establish diagnostic criteria for PD-1 inhibitor-related SC,more cases need to be evaluated.

Comprehensive insights into the effects and regulatory mechanisms of immune cells expressing programmed death-1/programmed death ligand 1 in solid tumors

The programmed cell death-1(PD-1)/programmed cell death ligand 1(PD-L1)signaling pathway is an important mechanism in tumor immune escape,and expression of PD-L1 on tumor cells has been reported more frequently.However,accumulating evidence suggests that PD-1/PD-L1 is also widely expressed on immune cells,and that regulation is also critical for tumor immune responses.In this review,we emphasized that under solid tumor conditions,the immunoregulatory effects of immune cells expressing PD-1 or PD-L1,affected the prognoses of cancer patients.Therefore,a better understanding of the mechanisms that regulate PD-1 or PD-L1 expression on immune cells would provide clear insights into the increased efficacy of anti-PD antibodies and the development of novel tumor immunotherapy strategies.

Programmed death-1/programmed death-L1 signaling pathway and its blockade in hepatitis C virus immunotherapy

Chronic hepatitis C virus(HCV) infection is a public health issue that often progresses to life-threatening complications, including liver cirrhosis, fibrosis, and hepatocellular carcinoma. Impaired immune responses to HCV are key features of chronic HCV infection. Therefore, intervention strategies usually involve enhancing the immune responses against HCV. Cytotoxic CD8+ T lymphocytes(CTLs) play a critical role in the control of HCV infection. However, their cytolytic function can be impaired by the expression of co-inhibitory molecules. Programmed death-1(PD-1) receptor and its ligand PD-L1 function in a T cell co-inhibitory pathway, which either blocks the function of CTLs or the differentiation of CD8+ T cells. During chronic HCV infection, the immune inhibitory receptor PD-1 is upregulated on dysfunctional HCV-specific CD8+ T cells. As such, blockade of the PD-1/PD-L1 pathway in these CD8+ T cells might restore their functional capabilities. Indeed, clinical trials using therapies to block this pathway have shown promise in the fostering of anti-HCV immunity. Understanding how chronic HCV infection induces upregulation of PD-1 on HCV specific T cells and how the PD-1/PD-L1 interaction develops HCV specific T cell dysfunction will accelerate the development of an efficacious prophylactic and therapeutic vaccination against chronic HCV infections, which will significantly improve HCV treatments and patient survival. In this review, we discuss the relationship between PD-1 expression and clinical responses and the potential use of PD-1 blockade for anti-HCV therapy.

Costimulatory molecule programmed death-1 in the cytotoxic response during chronic hepatitis C

Hepatitis C virus（HCV）-specific CD8^＋ T cells play an important role in the resolution of HCV infection. Nevertheless, during chronic hepatitis C these cells lack their effector functions and fail to control the virus. HCV has developed several mechanisms to escape immune control. One of these strategies is the upregulation of negative co-stimulatory molecules such us programmed death-1 （PD-1）. This molecule is upregulated on intrahepatic and peripheral HCV-specific cytotoxic T cells during acute and chronic phases of the disease, whereas PD-1 expression is low in resolved infection. PD-1 expressing HCV-specific CD8^＋ T cells are exhausted with impairment of several effector mechanisms, such as： type-1 cytokine production, expansion ability after antigen encounter and cytotoxic ability. However, PD-1 associated exhaustion can be restored by blocking the interaction between PD-1 and its ligand （PD-L1）. After this blockade, HCV-specific CD8^＋ T cells reacquire their functionality. Nevertheless, functional restoration depends on PD-1 expression level. High PD-l-expressing intrahepatic HCV-specific CD8^＋ T cells do not restore their effector abilities after PD-1/ PD-L1 blockade. The mechanisms by which HCV is able to induce PD-1 up-regulation to escape immune control are unknown. Persistent TCR stimulation by a high level of HCV antigens could favour early PD-1 induction, but the interaction between HCV core protein and gClq receptor could also participate in this process. The PD-1/PD-L1 pathway modulation could be a therapeutic strategy, in conjunction with the regulation of others co-stimulatory pathways, in order to restore immune response aclainst HCV to succeed in clearing the infection.

Polymorphisms in programmed death-1 gene are not associated with chronic HBV infection in Chinese patients

AIM:To investigate the association between the programmed death-1(PD-1) polymorphisms and genetic susceptibility of chronic hepatitis B virus(HBV) infection in Chinese patients.METHODS:Two single nucleotide polymorphisms(SNPs),PD-1.1 G > A and PD-1.2 G > A,were genotyped in 539 patients with chronic HBV infection and 353 other family members(HbsAg-) from 256 nuclear families using polymerase chain reactiorestriction fragment length polymorphisms assay.The associations between PD-1 polymorphisms and genetic susceptibilityof chronic HBV infection were analyzed usng the familybased association analysis method.RESULTS:No association or linkage was detected among 539 patients.Univariate(single-marker) familybased association tests demonstrated that PD-1 genotypes,alleles and transmitted haplotypes are not associated with chronic HBV infection(all with P value more than 0.05).Transmission/disequilibrium test and sibship disequilibrium test analysis showed no excess of the alleles from heterozygous parents to affected offspring(P = 0.688880,P = 1.000000 respectively).CONCLUSION:The data demonstrated that PD-1.1 and PD-1.2 polymorphisms are not associated with chronic HBV infection in Chinese patients.

Immunotherapy against programmed death-1/programmed death ligand 1 in hepatocellular carcinoma: Importance of molecular variations, cellular heterogeneity, and cancer stem cells

Hepatocellular carcinoma(HCC)is a heterogeneous malignancy related to diverse etiological factors.Different oncogenic mechanisms and genetic variations lead to multiple HCC molecular classifications.Recently,an immune-based strategy using immune checkpoint inhibitors(ICIs)was presented in HCC therapy,especially with ICIs against the programmed death-1(PD-1)and its ligand PD-L1.However,despite the success of anti-PD-1/PD-L1 in other cancers,a substantial proportion of HCC patients fail to respond.In this review,we gather current information on biomarkers of anti-PD-1/PD-L1 treatment and the contribution of HCC heterogeneity and hepatic cancer stem cells(CSCs).Genetic variations of PD-1 and PD-L1 are associated with chronic liver disease and progression to cancer.PD-L1 expression in tumoral tissues is differentially expressed in CSCs,particularly in those with a close association with the tumor microenvironment.This information will be beneficial for the selection of patients and the management of the ICIs against PD-1/PD-L1.

Regorafenib combined with programmed cell death-1 inhibitor against refractory colorectal cancer and the platelet-to-lymphocyte ratio’s prediction on effectiveness

BACKGROUND The effectiveness of regorafenib plus programmed cell death-1(PD-1)inhibitor in treating microsatellite stable(MSS)metastatic colorectal cancer(mCRC)remains controversial.AIM To investigate the benefits of regorafenib combined with PD-1 inhibitor in treating MSS mCRC and explore indicators predicting response.METHODS This retrospective study included a total of 30 patients with microsatellite stable metastatic colorectal cancer treated with regorafenib combined with programmed cell death-1 inhibitor at Henan Provincial People’s Hospital between December 2018 and December 2020.During a 4-wk treatment cycle,regorafenib was performed for 3 continuous weeks.PD-1 inhibitor was intravenously injected starting on the first day of the oral intake of regorafenib.We reviewed tumor response,progression-free survival(PFS),overall survival,and treatment-related adverse events(TRAEs)and evaluated association between platelet-tolymphocyte ratio(PLR)and outcomes in this retrospective study.RESULTS Stable disease and progressive disease were found in 18(60.0%)and 12(40.0%)patients,respectively.The disease control rate was 60.0%.The median follow-up time was 12.0 mo,and median PFS was 3.4 mo[95%confidence interval(CI):2.2-4.6 mo].Of the 12 patients with progressive disease,10(83.3%)had liver metastasis before starting the combined treatment.Among the 18 patients with SD,10(55.6%)did not have liver metastases.One patient without liver metastases at baseline was found with a substantially prolonged PFS of 11.2 mo.The liver metastasis,the choice of programmed cell death-1 inhibitor other than nivolumab or pembrolizumab and previous exposure to regorafenib was’t associated with treatment outcome.The median PFS in the low-PLR group was 4.2 mo(95%CI:3.5-4.9 mo),compared with 2.8 mo(95%CI:1.4-4.2 mo)in the high-PLR group(P=0.005).The major TRAEs included hand-foot syndrome(33.3%),hypertension(23.3%),malaise(20.0%),and gastrointestinal reaction(16.7%).The incidence of grade 3 TRAEs was 13.3%(4/30),which comprised abnormal capillary proliferation(n=1),transaminase elevation(n=1),and hand-foot syndrome(n=2).No grade 4 or higher toxicity was observed.CONCLUSION Regorafenib combined with PD-1 inhibitor could lead to a longer PFS in some patients with MSS mCRC.The PLR might be a prediction of the patient response to this therapy.

Anti program death-1/anti program death-ligand 1 in digestive cancers

Human tumors tend to activate the immune system regulatory checkpoints as a means of escaping immunosurveillance. For instance, interaction between program death-1(PD-1) and program death-ligand 1(PD-L1) will lead the activated T cell to a state of anergy. PD-L1 is upregulated on a wide range of cancer cells. Anti-PD-1 and anti-PD-L1 monoclonal antibodies(m Abs), called immune checkpoint inhibitors(ICIs), have consequently been designed to restore T cell activity. Accumulating data are in favor of an association between PD-L1 expression in tumors and response to treatment. A PD-L1 expression is present in 30% to 50% of digestive cancers. Multiple anti-PD-1(nivolumab, pembrolizumab) and anti-PD-L1 m Abs(MPDL3280A, Medi4736) are under evaluation in digestive cancers. Preliminary results in metastatic gastric cancer with pembrolizumab are highly promising and phase Ⅱ will start soon. In metastatic colorectal cancer(CRC), a phase Ⅲ trial of MPDL3280 A as maintenance therapy will shortly be initiated. Trials are also ongoing in metastatic CRC with high immune T cell infiltration(i.e., microsatellite instability). Major challenges are ahead in order to determine how, when and for which patients we should use these ICIs. New radiologic criteria to evaluate tumor response to ICIs are awaiting prospective validation. The optimal therapeutic sequence and association with cytotoxic chemotherapy needs to be established. Finally, biomarker identification will be crucial to selection ofpatients likely to benefit from ICIs.

PD-1及其配体在系统性红斑狼疮发病机制中的作用

PD-1（Programmed Cell Death-1，CD279）是一种新近发现的CD28免疫球蛋白超家族新成员，与CTLA-4（cytotoxic T-lymphocyte antigen-4）有23％的相同氨基酸序列。

PD-1/PD-L1抑制剂在肿瘤免疫治疗中的研究进展

肿瘤免疫治疗是目前肿瘤治疗领域的研究热点，在肿瘤的治疗过程中取得了显著的临床获益。程序性死亡受体-1（programmed cell death-1，PD-1）是目前备受关注的免疫抑制分子，其主要表达在激活的T细胞和B细胞中，PD-1与在肿瘤细胞中高表达的程序性死亡分子配体-1（programmed cell death ligand1，PD—L1）结合，激活PD-1信号通路，使得T细胞功能受损，

Immunostaining of PD-1/PD-Ls in liver tissues of patients with hepatitis and hepatocellular carcinoma

AIM: To investigate the expression of programmed death (PD)-1,PD ligand 1 (PD-L1) and PD-L2 in liver tissues in the context of chronic hepatitis and hepatocellular carcinoma (HCC).METHODS: Liver biopsies and HCC specimens from patients were collected and histologically examined.The expression of PD-1,PD-L1,and PD-L2 in biopsy specimens of chronic hepatitis and HCC specimens was evaluated by immunohistochemical staining.The association between the expression level of PD-1,PD-L1,and PD-L2 and clinical and pathological variables was analyzed statistically.RESULTS: Expression of PD-1 was found in liverinfiltrating lymphocytes.In contrast,PD-L1 and PD-L2 were expressed in non-parenchyma liver cells and tumor cells.The expression of PD-L1 was significantly correlated with hepatitis B virus infection (1.42 ± 1.165 vs 0.50 ± 0.756,P = 0.047) and with the stage of HCC (7.50 ± 2.121 vs 1.75 ± 1.500 vs 3.00 ± 0.001,P = 0.018).PD-1 and PD-Ls were significantly up-regulated in HCC specimens (1.40 ± 1.536 vs 5.71 ± 4.051,P = 0.000;1.05 ± 1.099 vs 4.29 ± 3.885,P = 0.004;1.80 ± 1.473 vs 3.81 ± 3.400,P = 0.020).CONCLUSION: PD-L1 may contribute to negative regulation of the immune response in chronic hepatitis B.PD-1 and PD-Ls may play a role in immune evasion of tumors.

Level of circulating PD-L1 expression in patients with advanced gastric cancer and its clinical implications

Objective：The programmed cell death-1 receptor/programmed cell death-1 ligand （PD-1/PD-L1） pathway plays a crucial role in tumor evasion from host immunity.This study was designed to evaluate the association between circulating PD-L1 expression and prognosis in patients with advanced gastric cancer.Methods：Totally 80 advanced gastric cancer patients and 40 health controls from Beijing Cancer Hospital were enrolled in the present study.Circulating PD-L1 expression was tested by enzymelinked immunosorbent assay （ELISA）.The associations between the expression level of PD-L1 and clinicopathological features and prognosis were analyzed statistically.Results：Expression of PD-L1 in advanced gastric cancer patients was significandy up-regulated compared with health people （P=0.006）.The expression of PD-L1 was significantly correlated with differentiation and lymph node metastasis （P=0.026 and P=0.041,respectively）.Although we didn＇t find significant difference in all advanced gastric cancer patients with different PD-L1 expression,the adenocarcinoma patients with higher up-regulated PD-L1 expression had much better prognosis than low expression patients （65.6％ vs.44.7％,P=0.028）.Conclusions：PD-L1 was elevated in advance gastric cancer patients and may play an important role in tumor immune evasion and patients prognosis.

PD-1/PD-L1 antagonists in gastric cancer:Current studies and perspectives

Immune checkpoints release suppressive signals for T cells,which enable the tumors to escape from immune destruction and provide a new concept that uses the capabilities of the immune system as a therapeutic target for tumors.At present,programmed death receptor 1(PD-1)/programmed death ligand-1(PDL1) has become the most promising therapeutic target.PD-1/PD-L1 blockades exhibit long-lasting antitumor efficacy and safety in patients with various cancers,such as melanoma and non-small-cell lung cancer.Moreover,PD-L1 is highly expressed in the peripheral blood and tumor specimens of patients with cancer,and the expression of PD-L1 is positively correlated with various pathological features and may serve as a predictor of poor prognosis or a diagnostic tool.Clinical trials have verified that PD-1/PD-L1 blockade therapy benefits patients with advanced gastric cancer or gastroesophageal junction cancer.Furthermore,there are many molecules involved in the regulation of PD-1/PD-L1 expression,and the modification of these molecules via drugs and combinations with PD-1/PD-L1 inhibitors may further improve the efficacy of immunotherapy for gastric cancer.In this review,the efficacy,safety,and possible combination treatment options of PD-1/PD-L1 in gastric cancer are reviewed in experimental and clinical settings.

阻断PD-1免疫检测点减轻阿尔茨海默病小鼠的病变并提高其认知能力

全身性免疫抑制会减弱机体的防护功能,而神经系统的修复需要细胞介导的免疫应答参与。Baruch等使用阿尔茨海默病（Alzheimer disease,AD）5个家族性基因突变（five familial AD mutations,5XFAD）的小鼠模型进行研究,