Oncogenes are important classes, or groups, of genetic mutations that cause cancer. They’re mutated forms of genes that control how cells grow and divide. Research shows specific oncogenes drive and support certain cancers. By targeting oncogenes, medical researchers have developed new ways to treat these cancers.
Oncogenes are a group of genetic mutations that may cause cancer. They’re a mutated form of genes that manage cell growth. When these genes change into oncogenes, they cause cells to grow and divide uncontrollably.
Oncogenes are powerful. Cancer typically happens when several genes mutate. But research shows a single oncogene may trigger cell growth that leads to cancer. Moreover, research shows certain kinds of cancer rely on oncogenes to survive. Understanding this relationship helps medical researchers develop treatments targeting oncogenes and effectively treating the cancers that oncogenes cause and support.
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To understand how oncogenes work, it may help to know more about proto-oncogenes. Proto-oncogenes are normal genes that may mutate or change and become oncogenes.
Your body contains trillions of cells. Each cell contains different kinds of genes that manage different activities. Proto-oncogenes drive the cell cycle, which is the process cells go through before they can divide. Proto-oncogenes also control how fast cells grow, when cells divide and when cells die (apoptosis).
When a proto-oncogene mutates and becomes an oncogene, the gene never stops sending signals telling cells to grow and divide. Cells respond by multiplying faster than usual, eventually creating tumors.
Proto-oncogenes mutate in three different ways:
Medical researchers aren’t sure why proto-oncogenes become oncogenes, but they suspect exposure to the following may play a role:
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Yes, there are. Medical researchers have linked about 100 different oncogenes to various kinds of cancer. For example, about 25% of all cancers involve various forms of Ras genes. Ras genes make proteins that manage how cells receive signals, grow and die.
Other oncogenes link to specific kinds of cancer, including:
No, they don’t. Research shows cancer happens when several genes within gene groups mutate. Oncogenes are one group or class of mutated genes that may cause cancer. Tumor suppressor genes that mutate are another class of genes that may cause cancer. Research shows oncogenes and tumor suppressor genes often work together to cause cancer.
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Typically, cancer happens after many kinds of genes mutate. For example, research suggests most cancerous tumors show signs of 30 to 60 different genetic mutations. But in some cases, cancer happens after just a few proto-oncogenes become oncogenes. It’s easier to target one genetic mutation than many mutations, making cancer treatment more effective.
For instance, medical researchers know chronic myelogenous leukemia (CML) happens when a single type of proto-oncogene mutates and becomes BCR-ABL oncogenes. The BCR-ABL oncogene makes abnormal enzymes that let abnormal white blood cells divide and multiply uncontrollably.
Tyrosine kinase inhibitor (TKI) drugs are used in targeted therapy that blocks abnormal BCR-ABL enzymes so the abnormal white blood cells die, putting CML into remission. (Remission means you don’t have cancer symptoms, and tests don’t find signs of cancer.) Before this treatment, only about 20% of people with CML were alive five years after diagnosis.
No, you can’t. Proto-oncogenes mutate or change into oncogenes after you’re born.
Experts don’t know all the reasons why proto-oncogenes mutate, which means there’s no sure way you can prevent the mutation that turns proto-oncogenes into oncogenes.
A note from Cleveland Clinic
Cancer research is the persistent and patient study of a multifaceted condition. Experts continually study cancer for new ways to treat it. Research into oncogenes — a group of genetic mutations that may cause cancer — changed how healthcare providers treat certain cancers. In some cases, knowing how oncogenes work has led to life-saving medical treatments.
If you have cancer, you may feel overwhelmed trying to understand what’s happening, and why. Some people with cancer benefit by learning about their condition, including research that’s already changed cancer treatment or may lead to changes. If that’s true for you, consider asking your healthcare provider to explain the specific genetic changes behind your condition.
Last reviewed on 05/01/2023.
Learn more about the Health Library and our editorial process.
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Cleveland Clinic is a non-profit academic medical center. Advertising on our site helps support our mission. We do not endorse non-Cleveland Clinic products or services. Policy