Houston Methodist. Leading Medicine.
Houston Methodist. Leading Medicine

Methodist Cancer Center - Texas Medical Center

Cell and Gene Therapy

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As we learn more about the genetic changes in cells that cause cancer, treatments are being developed to attack the disease on a cellular level. In gene therapy, genetic material (DNA or RNA) is introduced into the patient’s cells to correct defective genes and to help the body fight cancer.

Because gene therapy is still considered to be experimental, it is currently only available in clinical trials.

Houston Methodist Hospital, in conjunction with Baylor College of Medicine and Texas Children's Hospital, has established the Center for Cell and Gene Therapy (CAGT) to apply innovative and cost-effective cellular and genetic treatment options to our cancer patients.

How Gene Therapy Works
What to Expect From Gene Therapy
Side Effects and Risks of Gene Therapy
After Gene Therapy

How Cell and Gene Therapy Works
Your genes are the parts of your cells that contain DNA, the “code” that determines your body’s form and function. Researchers have found that certain genetic defects can cause a variety of diseases, including cancer.

Gene therapy as a cancer treatment can work in four different ways:

  • Replacing missing or mutated genes that have been shown to play a role in preventing or suppressing tumors (such as the p53 gene)
  • “Turning off” mutated genes that cause cancer or “turning on” healthy genes that prevent or help the body fight cancer
  • Inserting genes into cancerous cells to make them more evident to your body’s immune system
  • Changing the genes that control your normal immune cells so that they are better able to recognize and kill the cancer.

Since a gene cannot be inserted directly into a cell, it must be delivered using a carrier, also called a vector. The most commonly used vectors in gene therapy are viruses, which have a unique ability to recognize certain cells and insert genetic material into them. Stem cells and fat cells can also be used. There are two general approaches to introducing vectors into the body to deliver genetic content:

  • In ex vivo genetic therapy, cells are taken from your blood or bone marrow and introduced to the vector carrying the desired gene in the laboratory. The cells are grown in a culture in the lab and then reintroduced into the body.
  • In in vivo genetic therapy, vectors (usually viruses) containing the desired gene are injected directly into the patient’s body.

What to Expect From Cell and Gene Therapy
Your specific treatment will depend on the type of cancer you have and the type of gene therapy being used.

If ex vivo gene therapy is prescribed, the procedure will go something like this:

  • You may have blood drawn or a sample of your bone marrow taken.
  • The sample will be taken to the lab and introduced to the vector that carries the desired genetic material.
  • After the cells take in the genetic material, the sample is re-injected into your body through a vein.

With in vivo therapy, the vector is injected directly into the cancerous tissue, which then absorbs the genetic material.

Side Effects and Risks of Cell and Gene Therapy
Because cell and gene therapy is still in the experimental stage, certain risks are involved, especially when viruses are used as carriers for the genetic material.

  • Immune Response: Your body may attack the vector virus, which can lead to inflammation, toxicity and possibly organ failure.
  • Viral Spread: It’s possible that the virus may spread beyond the cells for which it was intended, which can cause damage to healthy tissue.
  • Reversion of the Virus: Researchers have found ways to remove the disease-causing genes from the viruses used as vectors; however, it is possible for the virus to revert to its original form once it’s inside the body.
  • Possibility of a New Tumor: If the genes are inserted in the wrong spot in the genome, the insertion could lead to the formation of a new tumor.

After Cell and Gene Therapy
As with any cancer treatment, it’s important to pay close attention to the instructions from your doctor and to know which warning signs to watch out for in the days and months following your procedure.

Learn more about cancer treatment:

For more information about cell and gene therapy at the Methodist Cancer Center or to make an appointment, call us at 713-790-2700.