Answer:
Proto-oncogenes can be described as normal genes of the body which are involved in cell growth and division.
The proto-oncogenes when mutated will have the ability to cause cancer, as the proto-oncogenes will become permanently activated by the mutation. Most probably they will cause the growth factors which bind to it to have rapid, abnormal divisions which will lead to cancer. The uncontrollable cell division will cause cancer. Hence, turning the normal proto-oncogenes into oncogenes or cancerous genes.