Abstract
The associations between programmed cell death ligand 1 (PD-L1) and the prognosis of various cancers have always been a research topic of considerable interest. However, the prognostic value of PD-L1 in breast cancer patients remains a controversial subject. We aimed to assess the association between PD-L1 protein expression and clinicopathological features and the impact of this relationship on breast cancer survival. We performed a systematic search of the PubMed, EMBASE, and Cochrane Library databases to determine the correlations among PD-L1 expression, clinicopathological features and overall survival (OS). A total of 5 studies containing 2,546 cases were included in the analysis. The combined hazard ratio (HR) and its 95% confidence interval (CI) for OS were 1.76 (95% CI 1.09–2.82; P=0.02) for patients with tumors exhibiting PD-L1 overexpression. The pooled odds ratios (ORs) indicated that PD-L1 expression was associated with positive lymph node metastasis, higher histological grades, estrogen receptor (ER)-negativity, and triple-negative breast cancer (TNBC). Our findings indicate that PD-L1 expression is a promising biomarker for the prognosis of breast cancer, and may be helpful to clinicians aiming to select the appropriate immunotherapy for breast cancer.
Highlights
Breast cancer is the most commonly diagnosed cancer and the leading cause of mortality in females worldwide [1]
programmed cell death ligand 1 (PD-L1) overexpression has been observed in various human malignancies, and a previous study has demonstrated that PD-L1 expression contributes to poor prognosis [21]
Our results demonstrate that PD-L1 can serve a significant biomarker in the poor prognosis of breast cancer
Summary
Breast cancer is the most commonly diagnosed cancer and the leading cause of mortality in females worldwide [1]. There are five main treatments for breast cancer, namely, surgery, radiotherapy, chemotherapy, targeted therapy and hormone therapy. It is imperative that researchers identify precise biomarkers of breast cancer and potential therapeutic targets for the treatment of the disease to improve survival. Blockade of the PD-1/PD-L1 pathway with monoclonal antibodies (against PD-1 or PD-L1) is a promising therapeutic approach that is currently being explored in studies of many types of human cancer [7]. The results of these studies suggest that PD-L1 plays an important role in tumors immune escapes by facilitating www.impactjournals.com/oncotarget
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