Monoclonal antibodies (mAbs) have revolutionized the landscape of cancer therapy by offering highly specific, targeted treatment options that differ significantly from conventional chemotherapeutic approaches. These laboratory-engineered antibodies are designed to recognize and bind selectively to antigens expressed on the surface of cancer cells, leading to direct or immune-mediated tumor cell destruction.

The therapeutic mechanisms of mAbs include blocking growth factor receptors, inducing apoptosis, recruiting immune effector functions such as antibody-dependent cellular cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC), and delivering cytotoxic agents via antibody–drug conjugates (ADCs). Notable examples include trastuzumab, which targets the HER2 receptor in breast cancer, and rituximab, which binds to CD20 in non-Hodgkin’s lymphoma. These treatments have significantly improved clinical outcomes, including progression-free survival and overall response rates.

Monoclonal antibodies can be classified based on their function: naked antibodies that act without a drug payload; conjugated antibodies linked to toxins or radionuclides; and bispecific antibodies designed to bind to two different antigens simultaneously. Additionally, immune checkpoint inhibitors such as nivolumab and pembrolizumab block PD-1/PD-L1 pathways, restoring the immune system’s ability to recognize and attack cancer cells.

Ongoing research in molecular oncology and immunotherapy is paving the way for personalized cancer therapy, in which monoclonal antibodies are selected based on the genetic and molecular profile of the tumor. Despite their success, challenges remain, including tumor antigen heterogeneity, resistance development, and adverse immune reactions.