Cancer cell stress ligands and tumor-associated antigens (TAA)

Cancer cell stress ligands and tumor-associated antigens (TAAs) represent a broad category of molecules that are either uniquely expressed or significantly overexpressed by malignant cells. Stress ligands, such as MHC class I polypeptide-related sequence A (MICA) and B (MICB), are typically induced by cellular stressors like DNA damage or malignant transformation and serve as ligands for the activating receptor NKG2D on natural killer (NK) cells and cytotoxic T cells [1][3]. Tumor-associated antigens include a variety of proteins such as differentiation antigens (e.g., CD20), overexpressed proteins (e.g., HER2, EGFR), and cancer-testis antigens (e.g., NY-ESO-1) [2][4]. These molecules are critical targets in oncology for the development of monoclonal antibodies, antibody-drug conjugates (ADCs), and adoptive cell therapies like CAR-T cells [5]. While they provide a mechanism for the immune system to distinguish tumor cells from healthy tissue, the fact that many TAAs are also expressed at low levels in normal tissues poses a risk for on-target, off-tumor toxicity [4][6]. Therapeutic strategies often aim to enhance the visibility of these ligands or block their immunosuppressive shedding to restore anti-tumor immunity [3].

Other names

Tumor-associated antigensStress-induced ligandsCancer antigensTAAsNKG2D ligandsTumor antigens

Therapeutic agents targeting these antigens primarily function by mediating the destruction of tumor cells through immune-based mechanisms, including antibody-dependent cellular cytotoxicity (ADCC), complement-dependent cytotoxicity (CDC), and the redirection of T-cells (e.g., via CAR-T or bispecific antibodies) [1][5]. Additionally, some agents block the signaling of overexpressed receptors (like HER2 or EGFR) to inhibit tumor cell proliferation and survival [2][6].