PD-L1 positivity was observed in 33% and 39% of primary melanomas and matched metastases, respectively, with, however, poor concordance between the primary and the matched metastatic site (κ = 0.283).
PD-L1 expression was analyzed by immunohistochemistry using two different antibodies in primary tumors and paired metastases from 81 melanoma patients treated at a single institution.
All patients receiving a single-agent ICI (cytotoxic T-lymphocyte-associated protein 4 [CTLA-4] or programmed death(ligand)1 [PD(L)-1] inhibitors) for the standard treatment of a locally advanced or metastatic cancer were included in this retrospective multicentric series.
Until now, anti-PD-L1 immunohistochemistry (IHC) on tissue sections has been the only validated companion diagnostic test for first-line immunotherapy for advanced and metastatic cancer, notably non-small-cell lung cancer (NSCLC).
PD-L1 expression (clone SP142) was investigated in esophageal adenocarcinomas using tissue microarrays (TMA) from 112 primary resected tumors, preoperative biopsies and full slide sections from a subset of these cases (n = 24), corresponding lymph node (n = 55) and distant metastases (n = 17).
We herein characterize PD-L1 expression in breast cancers across the full range of histomorphologies and investigate its intratumoral heterogeneity and fidelity across primaries and metastases.
Positive PD-L1 expression was found in 13% of primary tumours, 25% of relapses and 48% of metastases and correlated with a high T-cell infiltrate (p = 0.002).
Although there is no difference in infiltrating CD8<sup>+</sup> T cells between UM and CM, a significant decrease in programmed death-1 (PD-1)-positive lymphocytes was observed and lower levels of programmed death ligand-1 (PD-L1) in UM metastases compared with CM metastases.
PD-L1 is frequently expressed in intracranial SFT/HPCs, and diffuse or intense PD-L1 expression might be associated with the early occurrence of extracranial metastases.
The concordance of PD-L1 positivity between EBUS-TBNA and other specimens was moderate; κ = 0.63 for EBUS-TBNA vs. TBB, κ = 0.68 for EBUS-TBNA vs. resected primary tumors, and κ = 1.0 for EBUS-TBNA vs. resected metastases.
Patients with metastatic cancer (<i>n</i> = 198) were analyzed by flow cytometry for DC-HIL or PDL1 expression on blood CD14<sup>+</sup>HLA-DR<sup>no/lo</sup> MDSCs.
<b>Methods:</b> CD163<sup>+</sup> macrophages, CD3<sup>+</sup> T-cells, PD-L1/PD-L2 and HLA class I expression (HCA2, HC10 and β2m) were evaluated using immunohistochemistry in primary tumors (n = 75), local relapses (n = 6) and metastases (n = 19) of 87 LMS patients, as well as in benign leiomyomas (n = 7).
PD-L1 is also expressed on the K7M2 osteosarcoma tumor cell line that establishes metastases in mice, and PD-1 is expressed on tumor-infiltrating CTLs during disease progression.
As platelets help protect tumor cells from immune elimination in the circulatory system, we hypothesized that tumor PD-L1 and circulating platelets might synergistically promote tumor metastasis, and that the prognostic significance of PD-L1 might vary according to platelet count.
Moreover, in vivo anti-tumor studies reveal that Au@Pt-LM<sup>D</sup>P nanosystem can effectively eliminate primary tumors via PTT, and further stimulate the activation of cytotoxic T lymphocytes by PD-L1 immune checkpoint blockage, result in inhibiting the growth of distal tumors and alleviating tumor metastasis.