Programmed Deaths

An important aspect of cancer development is the acquisition of the ability of tumor cells to evade and deceive the immune system. This is because the immune system is, as immunologists like to say, a ‘vigilant’ system. It is constantly searching not only for pathogens and foreign agents but also for pre-malignant cells, with the aim of destroying them before they become tumors. Therefore, from the tumor’s perspective, it is necessary to develop mechanisms to become invisible to immune cells (some of which are poetically called Natural Killers).

One of the strategies used by tumor cells is the expression of molecules capable of binding to receptors on the membrane of immune cells, called Programmed Death-1 (PD-1). Binding to these programmed death receptors deactivates the immune cells, making them blind to the presence of tumor cells.

Today, there is a class of drugs capable of inhibiting this mechanism and “opening the eyes” of the immune cells again. These molecules are some of the most advanced (and expensive) therapies available for treating tumors that express these receptors.