Relationship between PD-L1 expression and clinical characteristics in patients with breast invasive ductal carcinoma

Objective. To evaluate the expression of PD-L1 (programmed death 1 ligand 1, PD-L1) and its clinical significance in breast invasive ductal carcinoma. Methods: Tumor samples were collected from 64 cases of breast invasive ductal carcinoma patients, and tumor adjacent normal breast tissue were obtained as normal control. The expression of PD-L1 were examined by immunohistochemical staining and real time PCR assay, its correlations with patients' clinical pathological characteristics were analyzed. Results. PD-L1 was found to be over-expressed in 24 of 64 (37.5%) breast invasive ductal carcinoma samples, while in 1 of 22 (4.5%) tumor adjacent normal breast tissue which indicated PD-L1 was higher expressed in breast invasive ductal carcinoma samples than the tumor adjacent normal breast tissue (P < 0.05). PD-L1 positive expression was associated with clinical pathological characteristics of TNM stage and pathology grading (P < 0.05). However, PD-L1 positive expression was not correlated with age (P > 0.05), menstruation status (P > 0.05), family history of breast cancer (P > 0.05), tumor diameter (P > 0.05), lymph node metastasis (P > 0.05) and tumor location (P > 0.05). Conclusion. PD-L1 may play an important role in invasive ductal carcinoma, which could be a potential indicator for advanced clinical stage and poor prognosis.