Prognostic prospect of soluble programmed cell death ligand-1 in cancer management

Abstract

Aggressive tissue biopsy is commonly unavoidable in the management of most suspected tumor cases to conclusively verify the presence of cancerous cells through histological assessment. The extracted tissue is also immunostained for detection of antigens (tissue tumor markers) of potential prognostic or therapeutic importance to assist in treatment decision. Although liquid biopsies can be a powerful tool for monitoring treatment response, they are still excluded from standard cancer diagnostics, and their utility is still being debated in the scientific community. With a myriad of soluble tissue tumor markers now being discovered, liquid biopsies could completely change the current paradigms of cancer management. Recently, soluble form of PD-L1 (sPD-L1), which is found in the peripheral blood, i.e. serum and plasma, has shown potential as a pre-therapeutic predictive marker as well as a prognostic biomarker to monitor treatment efficacy. Thus, this review focuses on the emergence of sPD-L1 and promising technologies for its detection in order to support liquid biopsies for future cancer management.

Research progress and value of albumin-related inflammatory markers in the prognosis of non-small cell lung cancer: a review of clinical evidence

“…Anti-PD-1 monotherapy reduces T-cell apoptosis and improves neutrophil and monocyte function. It has shown promising results in NSCLC treatment [ 98 ]. The increase in immunotherapy has increased the 5-year survival rate of NSCLC patients from 5% to 26% [ 99 ].…”

“…Along with the use of immunotherapy, markers to predict prognostic risk and drug response in NSCLC patients receiving immunotherapy have been sought. Tumor mutational load (TMB) [ 100 ], epidermal growth factor receptor (EGFR) mutations [ 101 ], and soluble programmed cell death ligand-1 (sPD-L1) [ 98 ] can predict response to immunotherapy. However, their detection is cumbersome and expensive.…”

Circulating proteins as predictive and prognostic biomarkers in breast cancer

“…In breast cancer patients, PD-L1’s expression in cancer cells is associated with response to NAC and OS [ 103 , 104 ]. Interestingly, PD-L1 in exosomes and more specifically soluble PD-L1 appears as a credible predictive and prognostic marker to monitor treatment efficacy in a myriad of cancers including breast, gastric, urothelial, esophageal or hepatocellular cancers [ 124 – 130 ]. In addition, serum PD-L1 mRNA expression in blood mononuclear cells could be associated with disease progression in breast cancer [ 131 ].…”

Prognostic significance of soluble PD-L1 in prostate cancer

“…Recently, soluble checkpoints PD-L1 and PD-1 (sPD-L1 and sPD-1), whose precursors are membrane bound PD-L1 and PD-1, have been the subject of intense research for their prognostic and predictive value in various cancers ( 4 , 5 ). The dynamic alterations of membranous PD-L1 in the circulatory system, including sPD-L1 and other forms of PD-L1, are attributed to liquid biopsy technique ( 6 ).…”