Immunotherapy for cancer
When we talk about cancer, we tend to imagine this once-per-life occurrence that ends in death or severe morbidity, and this perception is partly due to the grim outcome of many cancers. However, the reality is quite different, and cancer is far from being a rare occurrence on the microscopic level. Our cells are in a constant state of division and genetic errors are common. What prevents these errors from progressing to full blown cancer are many mechanisms including those responsible for repairing any errors of genetic division or the self-destruction of cells whose errors are beyond repair. The destruction of such cells can be either auto where the cell digests itself, a process called apoptosis, or by the immune system.
Cancers escape such mechanisms by both causing a mutation in the genes that are responsible for repair or self-destruction -also called tumor suppressor genes- and by deceiving the immune system into thinking that they are normal. The concept of immunotherapy is to help the immune system identify an invading organism or cancer or to damage it.
Regarding monoclonal antibodies, it was thought that this binding alone can selectively kill all cancer cells and spare all normal ones, but the reality is far more complex. For immunotherapy to work properly, a monoclonal antibody has to target a vital cellular structure that is only present in cancer cells. Cellular receptors work by sending and receiving signals and then giving orders that control cellular division and survival. Mutations sometimes manifest as abnormal receptors making targeting cancer cells feasible.