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.