Tyrosine kinases are signaling molecules that are frequently mutated as cells become tumorigenic. One of their responsibilities is regulating a cell’s growth based on the extracellular signals they receive. The presence of extracellular growth factors tells them to induce the cell to grow more rapidly, while a lack of oxygen or nutrients tells them to grow more slowly. When these kinases are mutated they make the cell grow uncontrollably, divorcing growth from the conditions outside the cell. In some cases, this mutation is what makes a cell cancerous.
A naturally occurring growth factor significantly boosted retention and prevented forgetting of a fear memory when injected into rats’ memory circuitry during time-limited windows when memories become fragile and changeable. In a study funded by the National Institutes of Health (NIH), animals treated with insulin-like growth factor (IGF2) excelled at remembering to avoid a location where they had previously experienced a mild shock .