[Human telomerase reverse transcriptase as a novel target for tumor immunotherapy].

Recently, a new immunotherapy against cancer based on a novel tumor-associated antigen of the human telomerase reverse transcriptase (hTERT) is being investigated. Antigen peptides derived from hTERT are expressed and presented with major histocompatibility complex (MHC) class I molecules in tumor cells, and elicit ex vivo cytotoxic T-lymphocyte (CTL) responses in healthy individuals and cancer patients. Data from both human and murine systems demonstrate that TERT-special CTL kill TERT-positive tumor cells of various histological origins in a MHC-restricted fashion. However, they do not lyze rarely normal cell types such as hematopoietic progenitor cells and activated T-lymphocytes in which telomerase has been detected. Phase I clinical trials targeting hTERT in advanced cancer patients further confirmed that there was little influence on autoimmunity. These results suggested that the possibility of broad spectrum immunotherapy or even immunoprevention therapy based on hTERT could be considered.