Co-Regulation of Immune Checkpoint PD-L1 with Interferon-Gamma Signaling is Associated with a Survival Benefit in Renal Cell Cancer

Programmed death ligand (PD-L1)-based immune checkpoint blockade therapy for metastatic renal cell carcinoma (RCC) achieves significant response rates in a subgroup of patients. The relevance of PD-L1 gene regulation for disease outcome is not clear.

The findings suggest that ccRCC and pRCC differ with respect to PD-L1 regulation by IFN-γ-signaling. High PD-L1-mRNA levels in tumor tissues with a positive IFN-γ signature favorably affect OS and DFS.

To evaluate PD-L1 expression and its dependence on interferon-γ (IFN-γ) in RCC cell lines and tissues in relation to disease outcome.

In ccRCC-like cell lines, PD-L1 was induced by canonical IFN-γ signaling, whereas in a pRCC-like cell line, PD-L1 was refractory towards IFN-γ signaling. In ccRCC and SKCM tissues, GSEA revealed significant IFN-γ pathway activation in tissue samples with high PD-L1-mRNA levels. This was not observed in pRCC tissue. ccRCC and SKMC patients with low PD-L1-mRNA levels had significantly shorter OS and DFS than those with high PD-L1-mRNA levels. In pRCC patients, no significant difference in OS and DFS with regard to PD-L1-mRNA tissue levels was obvious. Conclusions: The findings suggest that ccRCC and pRCC differ with respect to PD-L1 regulation by IFN-γ-signaling. High PD-L1-mRNA levels in tumor tissues with a positive IFN-γ signature favorably affect OS and DFS.