Conventional treatment with an anti-PD-L1 monoclonal antibody had no significant anti-tumor effect, indicating that early, self-activating expression of antiPD-L1-gamma1 can overcome the immunosuppressive environment in MMC tumors.
PD-L1 expression in TC and immune cells (IC) was manually scored in 27 head and neck squamous cell carcinoma (HSCC), 30 urothelial carcinoma (UC) and breast carcinoma (BC) using three commercial clones (SP263, SP142, 22C3) and one platform-independent test (E1L3N).
PubMed and Embase were searched for all original English-language articles published before January 30, 2019; all articles reported the predictive and prognostic implications of PD-L1<sup>+</sup> in breast cancer.
SLC1A5, SLC7A5, SLC3A2 and immune cell markers CD3, CD8, FOXP3, CD20 and CD68, in addition to PD1 and PDL1, were assessed by using immunohistochemistry on TMAs constructed from a large BC cohort (n = 803).
Among the breast cancer subtypes, evaluation of ICB has been of greatest interest in triple-negative breast cancer (TNBC) due to its immunogenicity, as evidenced by the presence of tumor-infiltrating lymphocytes and elevated PD-L1 expression relative to other subtypes.
This review provides clinicians with an overview of the available clinical evidence regarding PD-L1 as a biomarker in breast cancer, focusing on both data with a possible direct impact on clinic and methodological pitfalls that need to be addressed in order to optimize PD-L1 implementation as a clinically useful tool for breast cancer management.
Based on analysis of breast cancer tissue samples deposited in The Cancer Genome Atlas (TCGA), we found a positive correlation between PD-L1 and focal adhesion kinase (FAK) mRNA expression in PD-L1-positive (PD-L1<sup>+</sup>) TNBC, suggesting a functional association of FAK and immune checkpoints.
Triptolide, a natural compound purified from the Chinese herb Tripterygium wilfordii, has been reported to inhibit PD-L1 otherwise known as the B7 homolog 1 (B7-H1) expression in breast cancer.
Our preclinical data suggest that anti-PD-L1 plus sunitinib may warrant further investigation as an adjuvant therapy for RCC, while anti-PD-L1 may be improved by combining with chemotherapy in the neoadjuvant but not the adjuvant setting of treating breast cancer.
To conclude, PD-1 and tumor and immune PD-L1 seem to be discordantly expressed between primary tumors and their matched distant metastases in about one-third to a half of the breast cancer patients.
We generated a peptide assembling tumor-targeted nanodelivery system based on a breast cancer homing and penetrating peptide for the codelivery of a programmed cell death ligand 1 (PD-L1) small interfering RNA (siRNA) (siPD-L1) and an indoleamine 2,3-dioxygenase inhibitor as a dual blockade of an immune checkpoint.
The findings of D'Arcy et al suggest that immune surveillance controls oncogenesis and tumor progression in a broad range of malignancies and that breast cancer and pancreatic cancer could be sensitive to drugs targeting immune surveillance pathways other than those treated with currently Food and Drug Administration-approved antibodies to CTLA4 and PD-1/PD-L1.
Upregulation of PD-L1 expression in breast cancer cells through the formation of 3D multicellular cancer aggregates under different chemical and mechanical conditions.
The expression of phosphorylated signal transducer and activator of transcription 1 (p‑STAT1), one of the IFN‑γ signaling pathway molecules, was analyzed using immunohistochemistry (IHC) in relation to PD‑L1 and human leukocyte antigen (HLA) class I expression on cancer cells and tumor‑infiltrating CD8‑positive T cells in 111 patients with stage II/III breast cancer.
However, there is a limited research to prove the superior therapeutic efficacy of immunotherapy on breast cancer compared with melanoma and non-small-cell lung cancer because of its limited expression of PD-L1, low infiltration of cytotoxic T lymphocytes (CTLs), and high level of myeloid-derived suppressor cells (MDSCs).
Immune Checkpoint Blockade Mediated by a Small-Molecule Nanoinhibitor Targeting the PD-1/PD-L1 Pathway Synergizes with Photodynamic Therapy to Elicit Antitumor Immunity and Antimetastatic Effects on Breast Cancer.