The hunt for common tumor antigens.

The human immune system promotes survival by eliminating cells that display foreign antigens, such as peptides, from invading pathogenic microorganisms. Another source of such "nonself " antigens is through mutations of the host genome. This can occur during neoplastic transformation, whereby a normal somatic cell becomes malignant. Somatic mutations can result in altered or new proteins that are not present in normal cells, and these "neoantigens" are considered to be a main source of endogenous antitumor immunity. Genome sequencing has revealed that many cancers harbor dozens to hundreds of potential neoantigens, which might be harnessed to develop cancer immunotherapies and vaccines. On page 607 of this issue, Ely et al. (1) report common cryptic peptides that are generated from noncoding genomic regions in pancreatic cancer cells and that are not expressed by normal pancreatic cells. The strategy could uncover other noncoding, cancer-specific neoantigens that are otherwise hidden from traditional immunopeptidomic approaches. [ABSTRACT FROM AUTHOR]