Abstract
Simple SummaryThe role of PD-L1 expression in breast cancer remains controversial. Therefore, we performed a systematic review and meta-analysis to assess the association of PD-L1 expression with clinicopathological variables, overall survival (OS), and disease-free survival (DFS) in invasive breast cancer. PD-L1 expression was associated with age ≥ 50 years, lymph node status-negative, progesterone receptor-negative, Ki67 ≥ 20%, and human epidermal growth factor receptor 2 (HER2)-negative. PD-L1 positivity was associated with worse OS; however, there was no significant improvement in DFS. PD-L1 positivity was significantly associated with the clinicopathological characteristics of favorable and unfavorable prognoses. However, the final clinical outcome was associated with lower OS and had no significant association with DFS.Programmed death ligand 1 (PD-L1) has been investigated in various types of cancer; however, the role of PD-L1 expression in breast cancer remains controversial. We performed a systematic review and meta-analysis to assess the association of PD-L1 expression with clinicopathological variables, overall survival (OS), and disease-free survival (DFS) in invasive breast cancer. A total of 965 articles were included from CINAHL, Embase, PubMed, and Scopus databases. Of these, 22 studies encompassing 6468 cases of invasive breast cancer were included in the systematic review, and 15 articles were included in the meta-analysis. PD-L1 expression was associated with age ≥ 50 years, lymph node status-negative, progesterone receptor-negative, Ki67 ≥ 20%, and human epidermal growth factor receptor 2 (HER2)-negative. PD-L1 positivity was associated with worse OS (hazard ratio, HR, 2.39; 95% confidence interval, CI, 1.26–3.52; p =< 0.000); however, there was no significant improvement in DFS (HR 0.17; 95% CI −0.12–0.46; p =< 0.252). PD-L1 positivity was significantly associated with the clinicopathological characteristics of favorable and unfavorable prognoses. However, the final clinical outcome was associated with lower OS and had no significant association with DFS.
Highlights
The development of immunotherapy provides a new mechanism of action within systemic cancer therapy, as opposed to conventional treatments that lack tumor selectivity and cause adverse side effects [1,2]
This study investigated the association of programmed death ligand 1 (PD-L1) expression with clinicopathological characteristics, overall survival (OS), and disease-free survival (DFS) in invasive Breast cancer (BC) (IBC)
The proportion of PD-L1 expression was higher in tumor cells and immune cells (TCICs) (37%), followed by immune cells (ICs) (30%) and tumor cells (TCs) (19%)
Summary
The development of immunotherapy provides a new mechanism of action within systemic cancer therapy, as opposed to conventional treatments that lack tumor selectivity and cause adverse side effects [1,2]. These therapies use monoclonal antibodies against specific molecules that suppress the immune system, such as the programmed cell death protein (PD-1) and programmed death ligand 1 (PD-L1) [2]. The addition of PD-1/PD-L1 inhibitors to neoadjuvant chemotherapy has increased the pathological complete response rate in patients with triple-negative tumors [4,7]. Ongoing studies and new systematic reviews and meta-analyses are necessary to define the criteria of immunohistochemical positivity for PD-L1 and its association with the clinical course of BC. This study investigated the association of PD-L1 expression with clinicopathological characteristics, overall survival (OS), and disease-free survival (DFS) in invasive BC (IBC)
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