Melanoma-associated differentiation antigen (MDA) (MDA)

Melanoma-associated differentiation antigens (MDAs) are a group of proteins expressed specifically in melanocytes and their malignant counterpart, melanoma. This group includes well-characterized proteins such as MART-1 (Melan-A), gp100 (PMEL), tyrosinase, and tyrosinase-related proteins 1 and 2 (TRP-1, TRP-2) (Kawakami et al., 1994, PMID: 8168118; Bakker et al., 1994, PMID: 8168120). Biologically, these proteins are primarily involved in the melanogenesis pathway, facilitating the production and distribution of melanin pigment (Brichard et al., 1993, PMID: 8404582). Because they are highly expressed in melanoma cells but have limited expression in normal tissues—primarily the skin, eye, and inner ear—they serve as attractive targets for immunotherapy. Therapeutic strategies targeting MDAs include peptide vaccines, T-cell receptor (TCR) engineered T-cells, and bispecific T-cell engagers like tebentafusp, which targets gp100 in uveal melanoma (Nathan et al., 2021, PMID: 34551229). However, targeting these antigens can lead to on-target, off-tumor toxicities, such as vitiligo or uveitis, due to the destruction of healthy melanocytes (Yeh et al., 2009, PMID: 19433654). Monitoring for these antigens via immunohistochemistry is a standard practice for melanoma diagnosis and patient stratification in clinical trials.

Other names

Melanocyte differentiation antigensLineage-specific melanoma antigensMelanoma differentiation antigensMART-1/Melan-Agp100/PMEL17TyrosinaseTyrosinase-related protein 1 (TRP-1)Tyrosinase-related protein 2 (TRP-2)

Immune system activation via T-cell receptor (TCR) engagement, bispecific T-cell redirection, or antibody-drug conjugate (ADC) mediated cytotoxicity.