Kita-Kyushu lung cancer antigen 1 (KK-LC-1) peptide-HLA-A*01:01 complex (KK-LC-1/HLA-A*01:01)

Kita-Kyushu lung cancer antigen 1 (KK-LC-1), also known as Cancer/Testis Antigen 83 (CT83), is a protein that is highly expressed in various malignancies but has restricted expression in normal tissues, primarily the testis (UniProt Q5H943). The KK-LC-1 peptide (specifically the 52-60 epitope, RQKRILVNL) presented by the Human Leukocyte Antigen (HLA) class I haplotype, most notably HLA-A*01:01, serves as a highly specific target for cancer immunotherapy (PubMed: 33055356). Because the testis is an immune-privileged site lacking HLA expression, targeting this peptide-MHC complex minimizes the risk of on-target, off-tumor toxicity in healthy tissues (NIH NCI). Therapeutic strategies focusing on this target include T-cell receptor (TCR) engineered T-cell therapies, which are designed to recognize and eliminate tumor cells expressing the KK-LC-1 antigen (ClinicalTrials.gov: NCT03578406). Clinical interest is particularly high in epithelial cancers such as non-small cell lung cancer, gastric cancer, and triple-negative breast cancer, where KK-LC-1 expression is prevalent.

Other names

Cancer/testis antigen 83CT83KK-LC-1 peptide-MHC complexKK-LC-1(52-60) peptideRQKRILVNL-HLA-A*01:01

Engineered T-cell receptors (TCRs) recognize the specific KK-LC-1 peptide fragment (epitope 52-60) presented by HLA-A*01:01 on the surface of tumor cells, leading to T-cell activation and targeted cytotoxic lysis of the cancer cell.