Cancer is fundamentally a genetic disease. It occurs due to changes or mutations in the DNA of cells. These genetic alterations can disrupt normal cellular functions, leading to uncontrolled cell growth and division. Understanding the genetic basis of cancer can provide insights into its causes, progression, and potential treatments.
Genetic mutations can be inherited or acquired.
Inherited mutations are passed down from parents and are present in every cell of the body, while acquired mutations occur during a person's lifetime due to environmental factors, such as exposure to
carcinogens, or due to errors in DNA replication. These mutations affect critical genes that control cell growth, division, and death, leading to the development of cancer.
- Oncogenes are mutated forms of normal genes called proto-oncogenes. When proto-oncogenes are altered, they become oncogenes that promote excessive cell division and tumor growth.
- Tumor suppressor genes are genes that normally prevent cell growth or cause cell death. When these genes are inactivated or mutated, cells can grow uncontrollably, leading to cancer.
DNA repair mechanisms are crucial for maintaining the integrity of the genome. Cells have various repair pathways to correct DNA damage. When these
DNA repair mechanisms fail or are defective, mutations can accumulate, increasing the risk of cancer. For example, inherited mutations in the BRCA1 and BRCA2 genes, which are involved in DNA repair, significantly increase the risk of breast and ovarian cancers.
Several genetic syndromes are associated with an increased risk of cancer due to inherited mutations. Some examples include:
-
Lynch syndrome: Caused by mutations in DNA mismatch repair genes, leading to a higher risk of colorectal, endometrial, and other cancers.
-
Li-Fraumeni syndrome: Caused by mutations in the TP53 gene, resulting in a predisposition to various cancers, including sarcomas, breast cancer, and brain tumors.
-
Familial adenomatous polyposis: Caused by mutations in the APC gene, leading to the development of numerous polyps in the colon and rectum, which can progress to colorectal cancer if untreated.
Genetic testing can identify individuals with inherited mutations that increase their risk of cancer. This information can be used for:
-
Risk assessment: Individuals with a high genetic risk can undergo more frequent and earlier screenings to detect cancer at an early stage.
-
Preventive measures: Options such as prophylactic surgeries, lifestyle changes, and chemoprevention can be considered to reduce cancer risk.
-
Personalized treatment: Knowledge of specific genetic mutations in a tumor can guide targeted therapies, making treatment more effective and reducing side effects.
The field of cancer genetics is rapidly evolving, with advancements in technologies like
next-generation sequencing and
CRISPR gene editing. These innovations are enhancing our understanding of the genetic basis of cancer and opening new avenues for diagnosis, prevention, and treatment. As research continues, we can expect more precise and personalized approaches to cancer care, improving outcomes for patients.
