A key function of our immune system is to detect and eliminate foreign pathogens such as bacteria and viruses. Immune cells like T cells do this by distinguishing between different types of proteins within cells, which allows them to detect the presence of infection or disease.
A type of T cell called cytotoxic T cells can recognize the mutated proteins on cancer cells and should therefore be able to kill them. However, in most patients, cancer cells grow unchecked despite the presence of T cells.
