Human endogenous retrovirus type E antigen (HERV-E antigen)

Human endogenous retrovirus type E (HERV-E) antigen is a tumor-associated antigen derived from the reactivation of ancient retroviral sequences integrated into the human genome millions of years ago. While HERV-E is typically silenced in healthy adult tissues through epigenetic mechanisms like DNA methylation, it is selectively and robustly overexpressed in the majority of clear cell renal cell carcinoma (ccRCC) cases. This reactivation is primarily driven by the stabilization of hypoxia-inducible factor 2-alpha (HIF2α) following the loss of the von Hippel-Lindau (VHL) tumor suppressor, which leads to the transcription of HERV-E from its hypomethylated 5' long terminal repeat (LTR). The resulting proteins and peptides, such as the CT-RCC-1 peptide, are highly immunogenic and can be presented on the surface of tumor cells by HLA molecules, making them visible to the immune system. Due to its highly restricted expression in malignant cells and absence in normal tissues, HERV-E has emerged as a high-priority therapeutic target for cancer immunotherapies. Current clinical development efforts focus on adoptive cell therapies, including T-cell receptor (TCR) engineered T cells and chimeric antigen receptor (CAR) T cells, as well as therapeutic vaccines. These approaches aim to harness the specificity of the immune system to selectively eliminate HERV-E-expressing cancer cells while sparing healthy tissue. Early-phase clinical trials have demonstrated the feasibility of targeting HERV-E in patients with metastatic kidney cancer, though challenges remain regarding the long-term persistence and expansion of engineered T cells in vivo.

Other names

HERV-ECT-RCC antigenCT-RCC-1Human endogenous retrovirus ECT-RCC HERV-EHERV-E envelope protein

T-cell mediated cytotoxicity targeting HERV-E derived peptides (e.g., CT-RCC-1) presented on HLA molecules (e.g., HLA-A*11)