An Introduction to Proliferation and Migration of Stem and Cancer Cells

Throughout life, complex genetic systems regulate the balance between cell birth and death in response to growth and death signals. During early development, only a few cells abandon the cycle, but in several adult tissues, the cells normally do not proliferate, except during healing processes, which are supported by stem cells. However, in some adult tissues, cells continuously divide as a strategy for constant tissue renewal. In this context, cancer occurs when the control of growth and death is defective, driving the cells to an erroneous escape from death and causing intense cell proliferation. In the same way, the mechanisms and processes that coordinate cell migration are related to cell–cell contact and are important for homeostasis and the constitution of the organism. Moreover, migration is a normal event during embryo development and tissue regeneration; however, when regulation of migration fails, this can lead to a diverse number of diseases, including cancer. This chapter introduces the reader to the following specialized chapters on proliferation mechanisms written by experts in the field.