​https://youtu.be/h2rR77VsF5c

Summary

• Nearly all cancers are caused by mutations in the DNA of the abnormal cells.

• In non-cancerous cells, proto-oncogenes promote cell growth and mitosis prior to cell division; thus, proto-oncogenes encode proteins needed for normal cellular functions.

• In non-cancerous cells, tumor suppressor genes temporarily discourage cell growth and division to allow cells to finish routine functions, especially DNA repair.

• Mutations in proto-oncogenes and tumor suppressor genes may lead to cancer.

• Usually mutations in multiple genes are necessary to develop cancer.