***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
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    Input: PURPOSE Programmed death-1 ( PD-1 ) , an inhibitory receptor expressed on activated T cells , may suppress antitumor immunity . This phase I study sought to determine the safety and tolerability of anti-PD-1 blockade in patients with treatment-refractory solid tumors and to preliminarily assess antitumor activity , pharmacodynamics , and immunologic correlates . PATIENTS AND METHODS Thirty-nine patients with advanced metastatic melanoma , colorectal cancer ( CRC ) , castrate-resistant prostate cancer , non-small-cell lung cancer ( NSCLC ) , or renal cell carcinoma ( RCC ) received a single intravenous infusion of  anti-PD-1 ( MDX-1106 ) in dose-escalating six-patient cohorts at 0.3 , 1 , 3 , or 10 mg/kg , followed by a 15-patient expansion cohort at 10 mg/kg . Patients with evidence of clinical benefit at 3 months were eligible for repeated therapy . RESULTS Anti-PD-1 was well tolerated : one serious adverse event , inflammatory colitis , was observed in a patient with melanoma who received five doses at 1 mg/kg . One durable complete response ( CRC ) and two partial responses ( PRs ; melanoma , RCC ) were seen . Two additional patients ( melanoma , NSCLC ) had significant lesional tumor regressions not meeting PR criteria . The serum half-life of anti-PD-1 was 12 to 20 days . However , pharmacodynamics indicated a sustained mean occupancy of > 70 % of PD-1 molecules on circulating T cells > or = 2 months following infusion , regardless of dose . In nine patients examined , tumor cell surface B7-H1 expression appeared to correlate with the likelihood of response to treatment . CONCLUSION Blocking the PD-1 immune checkpoint with intermittent antibody dosing is well tolerated and associated with evidence of antitumor activity . Exploration of alternative dosing regimens and combinatorial therapies with vaccines , targeted therapies , and /or other checkpoint inhibitors is warranted BACKGROUND Blockade of programmed death 1 ( PD-1 ) , an inhibitory receptor expressed by T cells , can overcome immune resistance . We assessed the antitumor activity and safety of BMS-936558 , an antibody that specifically blocks PD-1 . METHODS We enrolled patients with advanced melanoma , non-small-cell lung cancer , castration-resistant prostate cancer , or renal-cell or colorectal cancer to receive anti-PD-1 antibody at a dose of 0.1 to 10.0 mg per kilogram of body weight every 2 weeks . Response was assessed after each 8-week treatment cycle . Patients received up to 12 cycles until disease progression or a complete response occurred . RESULTS A total of 296 patients received treatment through February 24 , 2012 .  Grade 3 or 4 drug-related adverse events occurred in 14 % of patients ; there were three deaths from pulmonary toxicity . No maximum tolerated dose was defined . Adverse events consistent with immune-related causes were observed . Among 236 patients in whom response could be evaluated , objective responses ( complete or partial responses ) were observed in those with non-small-cell lung cancer , melanoma , or renal-cell cancer .  Cumulative response rates ( all doses ) were 18 % among patients with non-small-cell lung cancer ( 14 of 76 patients ) , 28 % among patients with melanoma ( 26 of 94 patients ) , and 27 % among patients with renal-cell cancer ( 9 of 33 patients ) . Responses were durable ; 20 of 31 responses lasted 1 year or more in patients with 1 year or more of follow-up . To assess the role of intratumoral PD-1 lig and ( PD-L1 ) expression in the modulation of the PD-1-PD-L1 pathway , immunohistochemical analysis was performed on pretreatment tumor specimens obtained from 42 patients . Of 17 patients with PD-L1-negative tumors , none had an objective response ; 9 of 25 patients ( 36 % ) with PD-L1-positive tumors had an objective response ( P=0.006 ) . CONCLUSIONS Anti-PD-1 antibody produced objective responses in approximately one in four to one in five patients with non-small-cell lung cancer , melanoma , or renal-cell cancer ; the adverse-event profile does not appear to preclude its use . Preliminary data suggest a relationship between PD-L1 expression on tumor cells and objective response . ( Funded by Bristol-Myers Squibb and others ; Clinical Trials.gov number , NCT00730639 . ) Introduction : The Blueprint Programmed Death Lig and 1 ( PD‐L1 ) Immunohistochemistry ( IHC ) Assay Comparison Project is an industrial‐academic collaborative partnership to provide information on the analytical and clinical comparability of four PD‐L1 IHC assays used in clinical trials . Methods : A total of 39 NSCLC tumors were stained with four PD‐L1 IHC assays ( 22C3 , 28‐8 , SP142 , and SP263 ) , as used in the clinical trials . Three experts in interpreting their respective assays independently evaluated the percentages of tumor and immune cells staining positive at any intensity . Clinical diagnostic performance was assessed through comparisons of patient classification above and below a selected expression cutoff and by agreement using various combinations of assays and cutoffs . Results : Analytical comparison demonstrated that the percentage of PD‐L1–stained tumor cells was comparable when the 22C3 , 28‐8 , and SP263 assays were used , whereas the SP142 assay exhibited fewer stained tumor cells overall . The variability of immune cell staining across the four assays appears to be higher than for tumor cell staining . Of the 38 cases , 19 ( 50.0 % ) were classified above and five ( 13 % ) were classified below the selected cutoffs of all assays . For 14 of the 38 cases ( 37 % ) , a different PD‐L1 classification would be made depending on which assay/scoring system was used . Conclusions : The Blueprint PD‐L1 IHC Assay Comparison Project revealed that three of the four assays were closely aligned on tumor cell staining whereas the fourth showed consistently fewer tumor cells stained . All of the assays demonstrated immune cell staining , but with greater variability than with tumor cell staining . By comparing assays and cutoffs , the study indicated that despite similar analytical performance of PD‐L1 expression for three assays , interchanging assays and cutoffs would lead to “ misclassification ” of PD‐L1 status for some patients . More data are required to inform on the use of alternative staining assays upon which to read different specific therapy‐related PD‐L1 cutoffs Programmed cell death lig and ‐1 ( PD‐L1 ) is a lig and for programmed cell death‐1 ( PD‐1 ) that negatively regulates T‐cell activation and plays a crucial role in suppressing anti‐tumor host immunity . Although PD‐L1 is a promising immunotherapy target in various cancers , including urothelial carcinoma ( UC ) , the prognostic significance of PD‐L1 in UC is unclear . As platelets help protect tumor cells from immune elimination in the circulatory system , we hypothesized that tumor PD‐L1 and circulating platelets might synergistically promote tumor metastasis , and that the prognostic significance of PD‐L1 might vary according to platelet count . We immunohistochemically examined tumor PD‐L1 expression  in 271 patients with upper tract UC , which revealed PD‐L1 positivity in 31 of 271 cases ( 11 % ) . The associations of tumor PD‐L1 expression with outcomes varied among patients with high or low platelet counts ( Pinteraction < 0.004 ) . Among patients with high platelet counts ( N = 136 ) , PD‐L1 positivity ( N = 15 ) was significantly associated with shorter metastasis‐free survival ( univariate hazard ratio [ HR ] : 6.23 , 95 % confidence interval [ CI ] : 2.95‐13.1 ; multivariate HR : 2.68 , 95 % CI : 1.27‐5.64 ) and shorter overall survival ( univariate HR : 4.92 , 95 % CI : 2.14‐11.3 , multivariate HR : 2.78 , 95 % CI : 1.19‐6.51 ) . In contrast , among patients with low platelet counts ( N = 135 ) , PD‐L1 positivity ( N = 16 ) was not significantly associated with these outcomes . Our results suggest that tumor PD‐L1 expression and platelet count might interact and help regulate tumor progression . Although a larger prospect i ve study is needed to vali date our findings , this relationship is important to consider , as immunotherapies targeting the PD‐1/PD‐L1 axis have gained significant attention as promising therapies for UC 
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However , PD-L1 had relatively weak correlation with age , pathologic stage , lymph node metastasis and preoperative PSA level .
Conclusions : This meta- analysis confirms the negative prognostic significance of PD-L1 expression and mPD-L1 in PCa patients .
Additionally , PD-L1 has a statistically significant correlation with Gleason score and and rogen receptor status , while the correlations with age , pathologic stage , lymph node metastasis , and preoperative PSA level were not statistically significant .