Cancer cells expressing cognate antigens

Cancer cells expressing cognate antigens refers to a population of malignant cells that display specific molecular markers recognized by a corresponding therapeutic agent. These markers, or cognate antigens, can include tumor-associated antigens (TAAs) or tumor-specific neoantigens (NCI Dictionary of Cancer Terms). In the context of immunotherapy, these cells are the primary targets for modalities such as CAR-T cells, bispecific T-cell engagers (BiTEs), and antibody-drug conjugates (ADCs). The interaction between the drug and the cognate antigen triggers downstream effects such as direct cell lysis, apoptosis, or the delivery of cytotoxic payloads (Nature Reviews Drug Discovery, 2021). Biologically, these cells often utilize these antigens for signaling pathways that promote proliferation or survival. A major challenge in targeting these cells is antigen heterogeneity, where not all cells in a tumor express the target, leading to incomplete responses. Additionally, antigen escape occurs when cells downregulate the cognate antigen to evade the immune system or drug action (Nature Reviews Cancer, 2019). Safety concerns often involve on-target, off-tumor toxicity, which occurs if the cognate antigen is also expressed on vital healthy tissues. Identifying these cells through diagnostic biomarkers is essential for selecting patients likely to benefit from targeted therapies. Overall, this term describes a target cell population rather than a single, discrete molecular entity.

Other names

Antigen-positive tumor cellsTarget tumor cellsAntigen-bearing malignant cellsAntigen-expressing cancer cells

Selective binding to tumor-associated or tumor-specific antigens to facilitate immune-mediated cell death or targeted drug delivery.