Let's simply learn about cancer-causing genes (Oncogenes)?

We're all a little scared of the word "cancer," right? But have you ever wondered how this thing develops, and whether something in our own body could be the cause? In fact, changes in some of the genes that control the cells in our body are a major cause of cancer. Today, we're going to talk about a type of gene that can cause cancer. We call these oncogenes.

Simply put, what are these oncogenes?

An oncogene is a gene that can cause cancer. But it's not a bad gene that's always in our bodies. It's actually a mutated version of a very normal, healthy gene that controls the growth of cells in our bodies.

Think about it this way. We have a good, disciplined set of genes that control things like cell growth and division in our bodies. We call them proto-oncogenes . It's like the accelerator on a car. It's stepped on when it's needed and released when it's not. This is what controls cell growth to the desired level.

But, for some reason, if this good proto-oncogene changes, or mutates, it becomes an oncogene . What happens now? It's like the accelerator of that car is stuck on the floor. That is, this oncogene keeps sending signals to the cells to "divide, grow." It doesn't stop. So, over time, these abnormal cells that divide uncontrollably accumulate and form tumors .

It is very important for doctors to understand how these oncogenes work, because then they can target these oncogenes and find new drugs to treat cancer.

Oncogenes associated with various types of cancer

So far, more than 100 oncogenes have been identified as being involved in various types of cancer. For example, about one in five cancers is associated with various oncogenes in the Ras gene family.

Some oncogenes are more associated with specific types of cancer. Take a look at the table below to get a better idea of ​​this.

Why do these good genes turn bad?

The exact reason why this proto-oncogene turns into an oncogene is not really known, but it is believed that many of the things we know to cause cancer play a role in this.

• Excessive exposure to sunlight.
• Exposure to carcinogens (e.g., cigarettes, asbestos).
• Some viral infections.

These changes can occur in three main ways:

• Point mutation: Before our cells divide, they copy their DNA. During this copying, a small change in the DNA, such as the addition or deletion of a letter, can occur. This small mistake can turn a proto-oncogene into an oncogene.
• Gene amplification: Sometimes, more than one copy of a gene is produced on one of our chromosomes. In this way, if too many copies of a proto-oncogene are produced, its effect can be increased and cancer cells can grow.
• Chromosomal rearrangement: This is a bit more complicated. Simply put, a piece of one chromosome breaks off and swaps with a piece of another chromosome. We also call this process translocation . This swap can result in the formation of a new, active oncogene.

Why is it important to know about oncogenes for cancer treatment?

Usually, a cancer is caused by a combination of genetic mutations. But sometimes, a single oncogene can be powerful enough to start the entire cancer process.

Here's the good news: It's easier and more effective to target one major genetic mutation than to treat multiple genetic mutations at once.

A good example is chronic myelogenous leukemia (CML). Doctors have discovered that this leukemia is caused by a single oncogene called BCR-ABL. This oncogene produces an abnormal enzyme that causes abnormal white blood cells to divide uncontrollably.

Now there is a type of medicine called a tyrosine kinase inhibitor (TKI) . These medicines directly block the activity of the BCR-ABL enzyme. Then the abnormal white blood cells die. This treatment has allowed CML to go into remission. Before this medicine came along, only one in five people with CML lived for 5 years. But today, thanks to treatments that target this oncogene, patients are living much longer and healthier lives.

So is p53 also an oncogene?

No. p53 is a tumor suppressor gene . That means "a gene that stops tumor growth." But mutations in it can also cause cancer.

Let's go back to the car example.

• Proto-oncogenes are like the accelerator of a car.
• Tumor suppressor genes are like the brakes on a car.

An oncogene is like the accelerator being turned off. A tumor suppressor gene is like the brakes being turned off. In both cases, the vehicle called the cell continues to move without control, that is, it divides. So cancer can develop.

Some patients find it emotionally empowering to learn about cancer and try to understand what goes on inside. If you feel the same way, ask your doctor to explain the genetic changes that caused your condition in simple terms. This will help you better understand the treatment process.