Researchers at Jikei University School of Medicine (Tokyo, JAPAN) assessed retrospectively blood soluble OX40 (sOX40) levels in subjects (N=22) with advanced colorectal cancer (CRC) that 1) sOX40 levels were significantly higher compared with healthy adults, 2) sOX40 levels were positively correlated with blood levels of tumor biomarkers (CA 19-9, CEA), blood levels of CRP and soluble PDL-1, and negatively correlated with that of Albumin, and notably, 3) high blood sOX40 levels correlated with a reduced survival time. 

Sawada R et al. High blood levels of soluble OX40 (CD134), an immune costimulatory molecule, indicate reduced survival in patients with advanced colorectal cancer. Oncol Rep. 2019 Sep 6.

The interaction between OX40 on T cells and the OX40L on Antigen-presenting cells is a crucial step for T-cell activation and the promotion of anti-tumor immunity. So far preclinical studies revealed that the stimulation of OX40 using an agonistic anti-OX40 antibody or OX40L/Ig fusion protein bring about anti-tumor activity.

On the other hand, how sOX40 exists in blood in advanced cancer subjects and its clinical significance is so far unknown.

In the clinical settings, it is known that the immune status in the tumor microenvironment as well as infiltrating lymphocytes are both crucial factors that have impacts on tumor growth, metastasis, and its chemoresistance. A new anti-cancer drug targeting PD-L1 has appeared and drawing wide attention. It is of interest that this report revealed that high blood sOX40 levels correlated with a reduced survival in patient with advanced CRC, considering that its cell bound OX40 is a contributor of T-cell activation by an another pathway from PD-L1.

#27110 Human CD134/OX40 Assay Kit was used in this study. This assay is for research use only and not for use in diagnostic procedures.