Carbohydrate-rich tumor markers are specific antigens found either on the surface of tumor cells or may also be secreted as products by the tumor cells.
The carbohydrate tumor markers are classified as high-molecular-weight mucins and blood group antigen-related markers.
Monoclonal antibodies produced against carbohydrate-rich antigens are generally more specific and less prone to cross-reactivity than antibodies developed against hormones and enzymes.
In current nomenclature, the carbohydrate antigens are abbreviated "CA" and are also referred to more generally as "cancer antigens," followed by their number of discoveries, such as 125, 549, and so on.