The Influence of Drug-Eluting Beads Transarterial Chemoembolization on Serum Levels of Soluble Programmed Cell Death Protein-1 in Advanced Hepatocellular Carcinoma Patients

Aim

This study aims to explore the role of soluble programmed cell death protein 1 (sPD-1) in individuals with hepatocellular carcinoma (HCC) undergoing treatment with drug-eluting beads transarterial chemoembolization (D-TACE). Additionally, we aim to assess the potential utility of sPD-1 for determining the optimal timing for combining D-TACE with immune checkpoint inhibitors (ICIs).

Materials and Methods

A total of 44 HCC patients eligible for D-TACE and 55 healthy volunteers were enrolled in this study. Three milliliters of peripheral venous blood from the patients were collected on the day before D-TACE and 3, 7, and 30 days after D-TACE, respectively, for the assay of sPD-1. The relationships between sPD-1 levels, clinical features, outcomes, and the fluctuation of sPD-1 during treatment were analyzed.

Results

The initial sPD-1 levels in patients were found to be significantly higher than those in the control group. Although the initial sPD-1 levels displayed a decreasing trend with an increase in BCLC stage, no significant differences were observed among patients at different BCLC stages. The sPD-1 level on day 3 after D-TACE was similar to that on day 7 after D-TACE and significantly lower than the initial level. The sPD-1 level on day 30 after D-TACE was significantly higher than that on day 3 and day 7 after D-TACE and nearly returned to the initial level before D-TACE.

Conclusion

The level of sPD-1 was found to be significantly elevated in patients with HCC. However, further research is deemed necessary to fully understand the role of sPD-1 as a potential biomarker in the initiation, progression, and prognosis of HCC. The decrease in sPD-1 following D-TACE suggests that immune effector cells might potentially be reduced, as well as immune function weakened, highlighting the need to avoid the prompt administration of ICIs after D-TACE.

Soluble PD-1: Predictive, Prognostic, and Therapeutic Value for Cancer Immunotherapy

Programmed death protein 1 (PD-1) interaction with PD-L1 deliver immunosuppressive environment for tumor growth, and its blockade with directed monoclonal antibodies (anti-PD-1/anti-PD-L1) has shown remarkable clinical outcome. Lately, their soluble counterparts, sPD-1 and sPD-L1, have been detected in plasma, and elevated levels have been associated with advanced disease, clinical stages, and worst prognosis for cancer patients. Elevated plasma levels of sPD-L1 have been correlated with worst prognosis in several studies and has displayed a persistent outlook. On the other hand, sPD-1 levels have been inconsistent in their predictive and prognostic ability. Pretherapeutic higher sPD-1 plasma levels have shown to predict advanced disease state and to a lesser extent worst prognosis. Any increase in sPD-1 plasma level post therapeutically have been correlated with improved survival for various cancers. In vitro and in vivo studies have shown sPD-1 ability to bind PD-L1 and PD-L2 and block PD-1/PD-L1 interaction. Local delivery of sPD-1 in cancer tumor microenvironment through local gene therapy have demonstrated an increase in tumor specific CD8+ T cell immunity and tumor growth reduction. It had also exhibited enhancement of T cell immunity induced by vaccination and other gene therapeutic agents. Furthermore, it may also lessen the inhibitory effect of circulating sPD-L1 and enhance the effects of mAb-based immunotherapy. In this review, we highlight various aspects of sPD-1 role in cancer prediction, prognosis, and anti-cancer immunity, as well as, its therapeutic value for local gene therapy or systemic immunotherapy in blocking the PD-1 and PD-L1 checkpoint interactions.

Serum levels of soluble programmed death protein 1 (sPD-1) and soluble programmed death ligand 1 (sPD-L1) in advanced pancreatic cancer

Up to now, the efficacy of programmed death protein 1/programmed death ligand 1 (PD-1/PD-L1) blockade in pancreatic cancer (PC) remains uncertain. Serum levels of soluble PD-1 and PD-L1 (sPD-1/sPD-L1) have been reported to be independent prognostic factors in solid tumors susceptible to checkpoint blockade. Provenience, regulation and immunologic function of sPD-1 and sPD-L1 in cancer are poorly understood. To the best of our knowledge, sPD-1 and sPD-L1 have not been measured conjointly in any cancer type yet. In contrast to other tumor entities, sPD-1/sPD-L1 levels did not indicate an adverse outcome in a cohort of 41 patients with advanced PC. We observed a close positive correlation of sPD-L1 levels with sPD-1 in patients with advanced PC, suggesting a common provenience and regulation of sPD-1 and sPD-L1 in cancer patients. Higher sPD-L1 levels were present in patients with elevated C-reactive protein or strong tumoral T cell infiltration, while no correlation of sPD-L1 levels with tumoral PD-L1 expression was found. Our findings indicate that sPD-1 and sPD-L1 are markers of systemic inflammation in (pancreatic) cancer. In a subset of PC patients, elevation in sPD-L1 levels might be caused by an inflammatory tumor type - independent of tumoral PD-L1 expression.