termsTerm
Antigen
aka antigens, tumour antigen, tumour antigens, tumor antigen, tumor antigens, target antigen, target antigens, antigenic, tumour-associated antigen, tumour-associated antigens, tumor-associated antigen, tumor-associated antigens, antigen-negative, antigen loss
Anything an antibody or immune cell can recognise, typically a protein on a cell's surface. In cancer, an antigen is the flag that tells a drug or an immune cell 'this is the cell to attack'.
Most cancer antigens are ordinary human proteins that a tumour makes in unusual amounts (HER2, TROP2, CD19, PSMA), so drugs targeting them also touch normal cells that carry a little; truly tumour-specific antigens arise from mutations (neoantigens) or from viral proteins. A good drug antigen is abundant on tumour cells, scarce on essential normal tissue, and stable over time. Tumours escape by losing the antigen, which is how CD19-negative relapse defeats CAR-T, and by hiding the pieces of antigen they would normally display to T cells.
Category
Biology basics