RESUMO
Purpose To investigate the expression of programmed death ligand-1 (PD-L1) in breast cancer tumor cells and stromal tumor-infiltrating lymphocyte (sTIL),and to study the relationship between the expression of PD-L1 and the clinicopathological characteristics of the patients.Method The protein expression of PD-L1 was detected by immunohistochemistry of EliVision two-step method in 68 cases of non special type of invasive breast cancer,and the relationship between the expression of PD-L1 protein and the immunohistochemistry subtypes and clinical parameters was analyzed.Results The total expression rate of PD-L1 was 35.3％ in breast tumor tissue,specially in triple negative breast cancer (TNBC) which occupy the highest positive rate.The expression rates of PD-L1 in tumor tissue of the luminal subtype,HER-2 over-expression subtype and TNBC subtype were 16.1％,37.5％ and 61.9％ respectively,and the difference was statistically significant.The total expression rate of PD-L1 in sTIL was 51.5％,and the highest expression rate was 81.0％ in TNBC.There were significant differences of PD-L1 expression in sTIL of the luminal subtype,HER-2 over-expression subtype and TNBC subtype.Expression of PD-L1 in tumor tissue and sTIL had a significant positive correlation.Conclusion PD-L1 expressed in TNBC was significantly higher than other types of breast cancer,which suggest the blocking of signal pathway of PD-1/PD-L1 may expected to become a new immunotherapy for breast cancer,especially for TNBC subtype.