Tumor Suppressor genes tell healthy cells.
- When to slow down growth.
- When to repair the genetic material.
- When to destroy themselves (a process called
apoptosisthat’s used for abnormal or unneeded cells)
If the genes that control the growth of tumors are turned off, cells are at risk of becoming cancer-causing.
Most cancer cells have more than
Researchers will likely discover more of the tumor suppressor genes in the future. Tumor suppressor genes play a role in cancer development and treatment.
Every cell in your body contains long strands of tightly coiled DNA called chromosomes that carry your genetic information. You have 23 pairs of chromosomes in all your cells except for your sex cells. These cells only contain one pair of 23 chromosomes.
Your chromosomes contain approximately
Two types of genes are known to cause cancer.
- Tumor suppressor genes. These genes tell your cells when it’s time to slow down replication (copying themselves), repair DNA, or destroy themselves. Cancer can develop if these genes are turned off when they should be on.
- Oncogenes. These genes tell your cells when it’s time to grow. Cancer can develop if these genes are turned on when they should be turned off.
There are currently 73 known tumor suppressor genes
The University of Texas Tumor Suppressor Gene Database lists 73 tumor suppressor genes that may play a role in cancer development. It’s very likely that more genes will be discovered in the future.
Tumor suppressor genes are broadly divided into five categories:
- The progression of the cell cycle is controlled by certain genes.
- The cells are able to replicate by blocking genes that are involved.
- The cell cycle is stopped by genes.
- The cell self-destructs when there are certain genes.
- Errors in the DNA are repaired by genes.
Tumor suppressor gene mutations have been identified in
- Bladder cancer is a type of cancer.
- Breast cancer is a disease.
- Colorectal cancer is a type of cancer.
- Head and neck cancer.
- Lung cancer is a disease.
- Ovarian cancer is a disease.
- Pancreatic cancer is a disease.
- The cancer of the uterus.
Mutations in tumor suppressor genes can lead to tumor genesis, or the uncontrolled growth of cells. You have two copies of most genes in your body, one from each of your parents. Research has found that one copy of most tumor suppressor genes is enough to control cell division (a form of replication). This is called the two-hit hypothesis.
“Many tumor suppressor genes have been studied, and it is likely that many more haven’t been discovered yet. Some of the genes are well-known.”
|Retinoblastoma (RB) genes||Retinoblastoma and osteosarcomas||The
|Tumor protein P53 (TP53) gene||Bladder cancer is a type of cancer., breast cancer, brain cancers, and many others||This is the most commonly mutated gene in cancer cells. Mutations in TP53 are found in more than half of cancers.|
|Phosphatase and tensin homolog (PTEN) gene||Breast cancer is a disease., glial tumors, prostate cancer, melanoma, endometrial cancer||According to a
|Cadherin 1 (CDH1) gene (also known as E-cadherin gene)||Hereditary diffuse gastric cancer||According to the American Society of Clinical Oncology, men with this gene have an estimated 67%–80% chance of developing stomach cancer by age 80, and women have a 56%–83% risk of developing stomach cancer by this age. Women also have a 39%–52% risk of developing lobular breast cancer.|
|Neurofibromin 1 and 2 (NF1 and NF2) genes||Neurofibroma, brain tumors||Neurofibromatosis type 1 (caused by NF1 mutations) affects about
Genes can be passed on or acquired.
- Inherited gene mutations. Inherited gene mutations are present in the egg or sperm before they come together to create the first cell of your body. Every other cell in your body replicates from this first cell and carries the same mutations.
- Acquired gene mutations. Acquired mutations develop later in your life. They occur in a single cell and are then passed to any other cells that develop from this mutation.
Most tumor suppressor gene mutations are acquired not inherited. But most genes linked to inherited cancers are tumor suppressor genes. Most oncogene mutations are also acquired.
Researchers are continuing to improve their understanding of why some genes mutate. Mutations in the
Chemotherapy has long been a mainstream cancer treatment, but it often causes debilitating side effects due to damage to healthy cells. In recent years, researchers have been exploring how to use targeted therapies to treat cancer.
Targeted therapies leave healthy cells mostly undamaged by targeting cancer cells. Targeted gene therapy modifies genes.
Translating cancer research into new treatments is a long process. However, there’s been steady progress in developing drugs to target the TP53 gene and some other tumor suppressor genes.
Tumor suppressor genes tell healthy cells when to destroy themselves, slow their growth or repair their DNA. Cells can become cancer and grow out of control if there are defects in these genes.
There are more than 70 types of tumor suppressor genes. Researchers are looking at ways to target genes that are involved in cancer.