Common Antibody Targets

Anti-cancer monoclonal antibodies are very selective for cancer cells; they are able to identify which cells are malignant by markers on the cell surface.
CD stands for cluster of differentiation.  Each unique surface molecule or group of molecules that characterize a malignant cell is given a CD number assigned by an international group of scientists. (Some refer to CD as classification determinant.) A scientific method for characterizing cells based on surface molecules that allow different phenotypes to be identified. Over 300 numbers have been assigned and additional ones may be put on the list in the future.
CD molecules are often receptors. Monoclonal antibodies used for therapy often exploit this characteristic. They target the molecules and the MAB connects with the cancer cell.
GD2 is a disialoganglioside (a glycolipid) present on surface of some cancer cells
HER2 – human epidermal growth factor receptor 2
Nectin-4 – one of four immunoglobulin superfamily members (nectin-1 to -4).  Nectin-4 is known to contribute to tumor proliferation.
Somatostatin receptor – found expressed at relatively higher levels in many tumor cells
TROP-2 – Trophoblast cell surface antigen 2 (Trop-2) is a glycoprotein
BCMA – B-cell maturation antigen, also called CD269. CCR4 – C-C chemokine receptor type 4 – CD194
CTLA4 or CTLA-4 (cytotoxic T-lymphocyte-associated protein 4), also known as CD152, protein receptor
EGFR – Epidermal growth factor receptor, a tyrosine kinase receptor
GD2 is a disialoganglioside (a glycolipid) present on surface of some cancer cells
HER2 – human epidermal growth factor receptor 2
PD-L1 – programmed death ligand 1 – aka CD274.  The PD-1 (programmed cell death-1) receptor is expressed on the surface of activated T cells. Its ligands, PD-L1 and PD-L2, are expressed on the surface of dendritic cells or macrophages. PD-1 and PD-L1/PD-L2 belong to the family of immune checkpoint proteins that act as co-inhibitory factors that can halt or limit the development of the T cell response.
SLAMF7 aka CD319 – signaling lymphocyte activation molecule family member 7
VEGF – Vascular endothelial growth factor – protein in biochemical pathway that promotes the growth of new blood vessels.

VEGF explained

Vascular endothelial growth factor encompasses a number of biochemicals that play a part in the body’s functioning, especially in the development of new blood vessels.  VEGF is also called vascular permeability factor or VPF.  Subtypes include endocrine gland-derived vascular endothelial growth factor (EG-VEGF), VEGF-A (the first type discovered), VEGF-B, VEGF-C, VEGF-D, VEGF-E, VEGF-F (snake venom VEGF), and placenta growth factor (PlGF), which is important in the development of organs in embryos.
In the body, VEGF increases the permeability of the blood vessels and makes migration of cells easier.  It also promotes mitosis of the endothelial cells that line the blood vessels and hence causes angiogenesis.  New blood vessels arise from existing blood vessels through “sprouting” or “intussusception”.  Scientists have sought to interfere in this process with drugs that stop angiogenesis as a way to slow or stop the growth of cancerous tumors.
The other part of the VEGF mechanism is the cell receptors that VEGF binds to.  These are called VEGF receptors, or VEGFRs.  VEGFR-1 and VEGFR-2 are prevalent in blood vessels cells – the cells that line the blood vessels.  VEGFR-3 is prevalent in cells that line the structures that lymph travels through.

GD2 explained

Sphingolipids are a type of biomolecule that play roles in cell recognition and signaling.  They often sit on the surface of cells.  There are many types of sphingolipids and they do many things in single-celled organisms as well as mammals.  One type, the gangliosides, are important in human immunology as they function as cell markers.  The GD2 type of disialoganglioside shows up much more often on cancerous cells than on non-malignant ones, and drug designers seek to exploit this fact by creating antibodies that target GD2.
GD2 shows up in neuroblastomas, melanomas, retinoblastomas, and Ewing sarcomas
The medicines dinutuximab and naxitamab are on the market for neuroblastoma treatment as well as moxetumomab pasudotox for leukemia.  These and other investigational compounds either directly kill the malignant cells (apoptosis), make the malignant cells visible to the body’s immune cells which destroy the cancerous cells through phagocytosis, or disrupt the cellular membrane, leading to loss of integrity and inability to multiply.
It is also thought that these drugs can stop malignant cells in the blood or lymph from adhering to the extracellular body structures or taking up residence in the bone marrow.

EGFR explained

Epidermal growth factor (EGF) is a biochemical or group of biochemicals (proteins) instrumental in tissue development.  The factor stimulates division of cells and differentiation of cells.
EGF is part of a binary system – it connects to the epidermal growth factor receptor (EGFR) on the surface of cells.  The EGFR is also a protein that goes across the cell membrane and hence plays a part in the body’s signaling.  EGFR is part of the ErbB family of receptors.  It is also called ErbB-1 and HER1.
In many cancers, the EGFR is active.  Biochemists describe the situation by saying EGFR is overexpressed, dysregulated or mutated.  Medicines intended to block EGFR activity have been developed and include Gefitinib, Lapatinib, and Neratinib.
Related receptors in the ErbB family are HER2/neu (ErbB-2), Her 3 (ErbB-3) and Her 4 (ErbB-4).  These can also play a part in cancer progression and are potential targets for medicines.