A lot of times, cancer grows because there's a DNA mutationD-N-A MU-TAY-SHUN — A change in DNA that can lead to or cause cancer that causes proteinsPRO-TEEN — A naturally occurring, large, complex substance made up of amino acids that is an essential part of living organisms in cells to act abnormally. So, wouldn't it be smart if we could directly target those abnormalAB-NOR-MOL — Something that is not supposed to happen proteins and get them to stop? That's the idea behind targeted therapyTAR-GET-TED THAIR-AH-PEE — Anticancer medication that attaches to a specific protein receptor and blocks the receptor’s normal function to stop cancer growth.

Targeted therapy is a type of systemic treatmentSIS-TEM-IK TREET-MINT — Techniques targeting the whole body to eliminate or control a cancer that’s designed to block specific proteins that drive cancer cellSEL — One of the most basic components of all living things that together form the entire body and contains many smaller parts that guide its function growth. All cells have proteins, but the proteins that targeted therapy attacks are typically only found on the cancer cells and a few types of normal cells.

That means we can attack the cancer without damaging most normal cells—leading to better, more specific treatment with fewer side effects.

When doctors know what part of the cancer cell to attack (what’s driving a cancer cell’s growth), targeted therapy can work very well at stopping the cancer from multiplying. However, it doesn’t always work against every cancer, even if the cancer cells have the same targeted-proteins.

Let’s hop into your car so you can understand why this is the case.

A car with a hybrid engine can run on both gasoline and electricity. Some cancer cells are like this, too. More than one type of fuel can power them. If the treatment blocks only the electric engine, the gasoline engine can still run. Alternatively, if the treatment blocks the gasoline, the car will run off electricity.

Similarly, in cancer cells, a medication may block one protein in a cell. But if a different mechanism powers the cell, this block may not work to stop the cancer, or it only helps for a short time (becoming resistant to the treatment).

Therefore, targeted therapy works best when there’s only one type of "fuel" powering the car. However, it’s possible to combine several medications to try to stop multiple mechanisms at the same time.

Some targeted therapies target a single, very specific protein within the cell, while others attack groups of proteins (blocking several vital proteins inside and outside the cell). Either way, they’re both built on the same idea and work pretty similarly.

Let’s take a look under the hood.

Some normal proteins in cells can act like supercharged gasoline that makes a car go really fast and speed out of control. These proteins feed the cancer cells and make them grow uncontrollably.

To prevent cancer cells from growing, targeted therapy tries to starve the cancer cells of the supercharged fuel. The goal is to keep the gas out of the engine so the car stops running.