Purpose To investigate the expressions of costimulation molecules PD-L1 and PD-L2 in human breast cancers and their association with clinical and pathologic characteristics of the patients.Methods The expressions of PD-L1,PD-L2 in 10 cases of normal human breast tissue,18 cases of ductal carcinoma in situ,and 40 cases of breast cancer were detected by immunohistochemistry SP two-step staining,and the relationship between their expressions and clinical and pathologic characteristics was evaluated.Results There was no PD-L1 or PD-L2 expression in normal breast tissue,faint expressions of PD-L1 and PD-L2 were determined in ductal carcinoma in situ.45％ (18/40) PD-L1 and 35％ (14/40) PD-L2 were detected in breast cancers.PD-L1 and PD-L2 expression in cancer cells were related to the lymph node metastasis,ER and PR (P ＜ 0.05).High expression of PD-L1 and PD-L2 in breast cancer patients were correlated with negative ER,PR and HER-2 (P ＜ 0.05).Conclusion PD-L1 and PD-L2 express aberrantly in breast cancer and are closely associated with the lymph node metastasis of breast cancer.PD-L1 and PD-L2 may be the potential immunotherapy targets of breast cancer.

Objective To determine PD-L2 expression in human cervical squamous cell carcinomas and analyze its association with the clinical and pathologic characteristics of these cases ;observe the role of recombinant PD-L2 protein on apoptosis of active peripheral blood T lymphocytes of cervical carcinoma patients .Methods PD-L2 expression in cervical squamous cell carcinomas was determined by immunohistochemistry staining ,and the association between PD-L2 expression with the clinical and pathologic characteristics of these cases was analyzed .In vitro ,the peripheral blood T lymphocytes of cervical carcinoma patients were divided into blank group ,PD-L2 group and PD-L2+anti-PD-1 group respectively .After these active T cells were cultured 72 h ,their apop-totic rates were detected by flow cytometry .Results PD-L2 expressed in 53 .3% (32/60)cervical squamous cell carcinomas ,and it′s expression associated with lymph node metastasis of these cases (P< 0 .05) .In vitro ,PD-L2 promoted apoptosis of CD4+ T and CD8+ T lymphocytes ,the apoptotic rates were 17 .0% and 22 .4% respectively ,which were higher than 9 .0% and 16 .2% of blank group;however ,the apoptotic rates dropped to 11 .1% and 17 .5% in PD-L2+anti-PD-1 group .Conclusion PD-L2 aberrantly ex-presses in cervical squamous cell carcinomas and is associated with their lymph node metastasis .PD-L2 promotes apoptosis of T lymphocytes and depresses the anti-tumor immunity of cervical microenvironment ,and promotes lymph node metastasis of these cancers .PD-L2/PD-1 pathway may be a potential immunotherapy target of cervical squamous cell carcinomas .