Yes, cancer is considered a genetic disease. This means that it starts when there are changes, or mutations, in a cell's DNA. DNA is like a set of instructions that tells a cell how to grow, divide, and behave. When these instructions are altered, the cell may start to grow uncontrollably, leading to cancer.
How Does Cancer Occur?
Normally, cells in the body work together in a controlled way. They divide and make new cells only when needed. Before a cell divides, it makes a copy of its DNA so that each new cell has the same instructions. Sometimes, mistakes happen during this copying process. These mistakes are called mutations. Most of the time, the cell can fix these mistakes, but sometimes they go unnoticed.
If these mutations happen in certain important genes, they can cause the cell to grow and divide uncontrollably. There are two key types of genes involved:
- Proto-oncogenes: These genes tell the cell to grow and divide. If they mutate, they can become oncogenes, which tell the cell to keep multiplying even when it shouldn’t.
- Tumor Suppressor Genes: These genes tell the cell to stop growing. If these genes are mutated, the cell might keep multiplying without stopping.
For a cell to become cancerous, it usually needs several mutations in different growth-controlling genes. These mutations can build up over many years, which is why cancer is more common in older people.
The Cancer Cycle
When mutations occur in genes that control how a cell divides, the cell may start multiplying out of control. This can lead to a mass of cells called a tumor. At first, the tumor may stay in one place, but as it grows, it needs more nutrients. It starts to form its own blood vessels in a process called angiogenesis. Eventually, the cancer cells may spread to other parts of the body through the bloodstream or lymphatic system. This spread is called metastasis.
Genetic Predisposition
Some people are born with mutations that make them more likely to develop certain cancers. For example, some families have a history of colon cancer because of inherited mutations. People with these mutations might get cancer at a younger age, and the cancer is more likely to occur in multiple places in their bodies.
Environmental Factors
Cancer isn’t just about genetics; it’s also influenced by the environment and lifestyle. Things like exposure to the sun’s UV rays, chemicals in cigarette smoke, or radiation can damage DNA and lead to cancer. Certain lifestyle choices, like smoking or drinking too much alcohol, can also increase the risk of cancer. The relationship between environmental factors and cancer can be complicated and varies from person to person.
So, while cancer is a genetic disease at its core, many other factors play a role in its development.