Background/Aim: Programmed death-ligand 1 (PD-L1/CD274) elicits T-cell anergy, leading to immune suppression. We aimed to determine the prognostic relevance of PD-L1 expression in the blood of breast cancer (BC) patients. Materials and Methods: We measured PD-L1 mRNA expression in blood and tumor tissues of BC patients using RT-qPCR and a dataset from The Cancer Genome Atlas, and performed a survival analysis of PD-L1 expression in the blood of 330 BC patients. Flow cytometric analysis was performed using blood cells. Results: No statistical difference in PD-L1 expression was seen between normal controls and BC in blood or tissues. There was a significant positive correlation between the PD-L1 expression levels in blood and tissues. Decreased PD-L1 expression in blood or tissues was associated with poor recurrence-free survival. PD-L1 is mainly expressed in polymorphonuclear leukocytes. Conclusion: Low expression of PD-L1 in the blood could serve as a biomarker of poor prognosis in BC patients.
All Science Journal Classification (ASJC) codes
- Cancer Research