What keeps the body from growing constantly? The growth of the body depends both on cell division and cell differentiation and specialization. Cells must divide and they must form different kinds of cells to perform different functions. Uncontrolled cell division produces cancerous tissue. The rate of cell division is controlled by molecules known as growth factors as well as by environmental cues. One example of a growth factor is platelet-derived growth factor (PDGF). This growth factor is produced by platelets (a type of blood cell) in the vicinity of a wound. PDGF causes cell division, speeding the healing of the injury.
