This is a special type of colon cancer: Let's simply learn about MSI-H! (Microsatellite Instability-High Colon Cancer)

Have you noticed a change in your bowel habits, abdominal pain, or blood in your stool lately? Don't ignore these symptoms, thinking they're normal. They could be signs of colon cancer. Today, we're talking about a type of colon cancer that's a little bit more special, but also a bit more fortunate. It's called MSI-H.

Simply put, what is this MSI-H colon cancer?

To understand this, let's first take a look at the DNA inside our body's cells. Think of our DNA as a long chain. This chain has beads of the same type attached to it over and over again. These repeated segments of DNA are called microsatellites.

Now, when our body's cells divide and new cells are formed, copies of this DNA chain are made. Sometimes mistakes (mutations) can occur when these copies are made. But don't worry, our body has a system like a 'police that finds mistakes'. It's called the Mismatch Repair (MMR) system. It checks for mistakes in those DNA copies and corrects them immediately.

However, in some cancer cells, this MMR system does not work properly. We call it dMMR (deficient DNA Mismatch Repair). Then, because there is no one to fix the mistakes in those DNA copies, mistakes accumulate and the DNA becomes very unstable. That is the condition with highly unstable microsatellites, which we call MSI-H (Microsatellite Instability-High) .

What are the possible symptoms of MSI-H cancer?

Symptoms may not always appear, but if symptoms do appear, they are similar to those of typical colon cancer.

Important: Not everyone with these symptoms has cancer. However , if you have blood in your stool or severe stomach pain, see a doctor immediately. If other symptoms persist for more than two weeks, you should definitely seek medical advice.

Sometimes, the first sign of this cancer is a blood test showing a low red blood cell count (anemia). This is due to bleeding in the intestines.

Causes and risk factors for developing MSI-H cancer

The primary cause of MSI-H cancer is the defects in the MMR genes we talked about earlier. These often occur during one's lifetime, for no particular reason.

But in about 5% of people who develop colon cancer, this genetic defect is passed down through generations. We call this Lynch syndrome . If someone in your family has this condition, you are also at higher risk of developing colon cancer.

In addition, there are things in our lifestyle that increase the risk of cancer.

How to diagnose the disease?

If your doctor suspects cancer based on your symptoms, he will refer you for several tests.

1. Colonoscopy: A flexible tube with a camera attached is inserted through the anus to examine the entire colon. At this time, a small piece of tissue is taken from a suspicious area for examination. This is called a biopsy .

2. Molecular tests: Special tests are performed to detect genetic changes, i.e. MSI-H status, in the tissue sample taken from the biopsy. Technologies such as IHC , PCR , and NGS are used for this.

3. Imaging tests: Scans such as CT and MRI are done to see if the cancer has spread to other organs.

What are the treatments for MSI-H cancer?

Treatment depends on the stage of the cancer and how far it has spread. There are two main treatment options.

Surgery

If the cancer has not spread to other areas, the first step is to remove the tumor through surgery. The type of surgery may vary depending on the size of the cancer.

Medication

This is where the specificity of MSI-H cancer comes into play.

• Immunotherapy: This is the most important and successful treatment for MSI-H cancer. Think of our immune cells as having an 'on'/'off' switch. Cancer cells sometimes cleverly turn this switch off and hide from our body's defenses. Immunotherapy drugs (checkpoint inhibitors) turn that 'off' switch back on, helping the immune system find and destroy cancer cells.
• Chemotherapy: Giving strong drugs to kill cancer cells. Sometimes used before or after surgery.
• Targeted Therapy: Giving drugs that target and stop specific proteins or processes that help cancer cells grow.

Living with MSI-H cancer

It is very important to maintain good physical and mental health during cancer treatment.

• Diet: After surgery, follow your doctor's instructions and eat a diet that is easily digestible and high in protein. It is best to reduce the intake of gas-producing foods (e.g., cabbage, beans) and processed meats.
• Exercise: Simple exercises like walking as much as you can can be very beneficial for your body and mind. But check with your doctor before starting any exercise regimen.
• Mental health: It's normal to feel anxious and scared during times like these. Don't keep your feelings bottled up inside. Talk to someone you trust, your family, and seek help from a mental health counselor if necessary.

Colon cancer, MSI-H, colon cancer, cancer symptoms, immunotherapy, immunotherapy, MMR, Lynch syndrome, DNA