Cancer Growth and Metastasis
In a healthy body, the trillions of cells it’s made of grow and divide, as the body needs them to function daily. Healthy cells have a specific life cycle, reproducing and dying off in a way that is determined by the type of cell. New cells take the place of old or damaged cells as they die. Cancer disrupts this process and leads to abnormal growth in cells. It’s caused by changes or mutations in DNA.
DNA exists in the individual genes of every cell. It has instructions that tell the cell what functions to perform and how to grow and divide. Mutations occur frequently in DNA, but usually cells correct these mistakes. When a mistake is not corrected, a cell can become cancerous.
Mutations can cause cells that should be replaced to survive instead of die, and new cells to form when they’re not needed. These extra cells can divide uncontrollably, causing growths called tumors to form. Tumors can cause a variety of health problems, depending on where they grow in the body.
But not all tumors are cancerous. Benign tumors are noncancerous and do not spread to nearby tissues. Sometimes, they can grow large and cause problems when they press against neighboring organs and tissue. Malignant tumors are cancerous and can invade other parts of the body.
Some cancer cells can also migrate through the bloodstream or lymphatic system to distant areas of the body. This process is called metastasis. Cancers that have metastasized are considered more advanced than those that have not. Metastatic cancers tend to be harder to treat and more fatal.