Overview of advances in cancer immunotherapy

Cancers are tumors and tumors are by definition multicellular three-dimensional structures, measured at least at the millimeter level. A single cell with inappropriate features, even if it can be recognized under a microscope, will never be called a “tumor”. Tumors are tissues and as such, they are composed out of different types of cells with altered properties in a permissive environment. Potentially malignant cells in terms of genetic alterations, as we currently conceive them, may be produced upon programmed cell divisions but these are either non-viable or they are timely recognized by our immune system as “alien” or “non-self”, and destroyed.