Proto-Oncogenes and Normal Cell Growth
Oncogenes are related to normal genes called proto-oncogenes. Proto-oncogenes are a family of normal genes that code mainly for proteins involved in a cell's normal growth-control pathway. Cell growth and division is normally controlled by proteins called growth factors, which bind to receptors on the cell surface. This binding activates a series of enzymes inside the cell, which in turn activate special proteins called transcription factors inside the cell's nucleus. The activated transcription factors turn on genes required for cell growth and proliferation. Many components of this pathway, for example, growth factors signaling enzymes, receptors, and transcription factors, are encoded by proto-oncogenes.