NCIt definition : A 9-residued peptide vaccine consisting of amino acids 157 through 165 of the cancer/testis
(CT) antigen ESO-1. Modified at position 165 (cysteine to valine) to improve immunogenicity,
ESO-1:157-165(165v) peptide administered as a vaccine may stimulate the host immune
system to mount a cytotoxic T lymphocyte (CTL) response against tumor cells positive
for ESO-1, resulting in decreased tumor growth. ESO-1 is expressed in a variety of
cancers, including melanoma, breast, bladder, prostate, and hepatocellular cancers.
(NCI04);