Expression of PD-1/PD-L1 in triple-negative breast carcinoma and its significance

Objective: To investigate the correlation between the expression of PD-1, PD-L1 and clinicopathologic parameters in triple negative breast carcinoma (TNBC).

Methods: Samples from 151 patients with TNBC and 65 cases of other breast carcinomas (non-TNBC) were examined for PD-L1 and PD-1 expression by immunohistochemical staining on tissue microarray.

Results: The expression of PD-L1 and PD-1 in the tumor cells and interstitial lymphocytes in TNBC was significantly (P<0.05)higher than that in non-TNBC.In TNBC, the expression rates of PD-L1 in the cancer nests and stroma were 16.6%(25/151) and 25.2%(38/151)respectively.The former was positively correlated with tumor histological grade and lymph node metastasis (P<0.05), and the latter only with tumor histological grade (P<0.05). The expression rate of PD-1 was 27.2% (41/151), and correlated with PD-L1 expression in stromal tumor-infiltrating lymphocytes (P<0.05).

Conclusion: The expression of PD-L1 in TNBC is significantly correlated with high-grade histology, lymph node metastasis and PD-L1 expression in stromal tumor-infiltrating lymphocytes.