Final answer:
Proto-oncogenes become oncogenes through mutations that enhance their activity, resulting in uncontrolled cell division and cancer. The transformation requires multiple genetic changes, and an example of an oncogene is the myc protein, which causes B cells to proliferate uncontrollably in Burkett's Lymphoma.
Step-by-step explanation:
Proto-oncogenes are genes that normally function in the regulation of the cell cycle, promoting growth and reproduction of cells. These genes can mutate and turn into oncogenes, which cause cells to grow and divide uncontrollably, leading to cancer. The transformation of proto-oncogenes into oncogenes can occur through several mechanisms such as a mutation that results in a gain of function, changes in gene expression levels, or through the action of viral insertion near a proto-oncogene that leads to its overexpression.
One of the transformative processes is that a proto-oncogene, when mutated, may produce an abnormal version of its protein that is continuously active, resembling a car accelerator pedal stuck at full throttle, causing the cell to divide without control. This is critical in cancer because the unregulated cell division is a hallmark of tumor growth. An example of this transformation is the myc protein, which becomes an oncogene in Burkett's Lymphoma, leading to the unchecked proliferation of B cells and the formation of tumors that can disrupt normal bodily functions.
It is important to note that usually a series of mutations in multiple genes, including both proto-oncogenes and tumor suppressor genes, is needed for a normal cell to transform into a cancer cell. Cells implement several control mechanisms to guard against mutations in proto-oncogenes, but when these systems fail, and enough proto-oncogenes are activated while tumor suppressor genes are deactivated, the process that might lead to the transformation into a cancerous cell begins.