Tumor-associated and dark genome cancer antigens (TAA/DGA)

Tumor-associated and dark genome cancer antigens represent a diverse class of peptides presented by Major Histocompatibility Complex (MHC) molecules that serve as targets for T-cell mediated immunotherapy. While traditional tumor-associated antigens (TAAs) are derived from protein-coding genes overexpressed in tumors, 'dark genome' antigens originate from non-canonical regions such as introns, intergenic regions, endogenous retroviruses, and out-of-frame translations. These cryptic antigens are often highly tumor-specific because the genomic regions from which they derive are typically silenced in healthy adult tissues but become transcriptionally active during oncogenesis. By expanding the pool of targetable epitopes beyond the 2% of the genome that codes for proteins, these antigens provide new opportunities for treating 'cold' tumors with low mutational burdens. Therapeutic interventions targeting these antigens include personalized cancer vaccines, TCR-engineered T cells, and soluble TCR-based biologics. The primary challenge in targeting this class lies in the precise identification of immunogenic peptides and ensuring the absence of cross-reactivity with the normal self-peptidome to avoid autoimmunity.

Other names

Non-canonical cancer antigensCryptic antigensDark matter antigensUnconventional T-cell targetsTumor-specific antigens (TSA)Cancer-testis antigens (CTA)Retrotransposon-derived antigensMHC-associated peptides (MAPs)

These targets are recognized by T-cell receptors (TCRs) when presented as peptides on Major Histocompatibility Complex (MHC) molecules. Therapeutic strategies include cancer vaccines (mRNA or viral vectors) to prime the immune system, adoptive T-cell therapy (TCR-T) using engineered T cells to recognize specific peptide-MHC complexes, and bispecific T-cell engagers (BiTEs) that bridge T cells to the tumor-specific antigen.