Oncogenes are mutated forms of genes. Oncogenes can transform a cell into a tumor cell some tumor cells are benign while other are malignant how does the prensence of an oncogenes lead to the formation of a tumor
A proto-oncogene is a gene that is normally involved in cell growth. When it mutates or several copies of it are made, it becomes a "bad" gene (oncogene) that can become permanently turned on or activated when it is not supposed to be. When this happens, the cell grows out of control and accumulate to form a tumor.