Melanoma differentiation antigens (MDA)

Melanoma differentiation antigens (MDAs) are a group of proteins specifically expressed in cells of the melanocytic lineage, including normal melanocytes and malignant melanoma cells [PubMed: 10449301]. This group includes well-characterized proteins such as gp100 (PMEL), MART-1 (Melan-A), Tyrosinase, and Tyrosinase-related proteins 1 and 2 (TRP-1, TRP-2) [UniProt]. Biologically, these molecules are primarily involved in the process of melanogenesis and the structural formation of melanosomes, which are the organelles responsible for skin and eye pigmentation [PubMed: 10449301]. In oncology, MDAs serve as critical targets for various immunotherapeutic strategies, including cancer vaccines, T-cell receptor (TCR) engineered T-cells, and bispecific T-cell engagers, due to their high expression in melanoma [NIH]. Notable drugs in this space include Tebentafusp, a bispecific protein that targets a gp100 peptide presented by HLA-A*02:01 to redirect T-cells to tumor cells [FDA, 2022]. However, because these antigens are also present in healthy melanocytes, therapeutic targeting can lead to "on-target, off-tumor" toxicities such as vitiligo, uveitis, or hearing loss [PubMed: 22556005].

Other names

Melanocyte differentiation antigensMelanoma-associated differentiation antigensLineage-specific melanoma antigens

Immune system redirection via T-cell receptor engagement or antibody-mediated targeting of melanocytic lineage-specific proteins to induce cell death.