How cancer occurs in a cell

These tumors can occur almost anywhere in the body and can be either benign or malignant. Neuroendocrine tumors form from cells that release hormones into the blood in response to a signal from the nervous system. These tumors, which may make higher-than-normal amounts of hormones, can cause many different symptoms. Neuroendocrine tumors may be benign or malignant.

Our definition of neuroendocrine tumors has more information. Carcinoid tumors are a type of neuroendocrine tumor. They are slow-growing tumors that are usually found in the gastrointestinal system most often in the rectum and small intestine.

Carcinoid tumors may spread to the liver or other sites in the body, and they may secrete substances such as serotonin or prostaglandins, causing carcinoid syndrome. Our page on gastrointestinal carcinoid tumors has more information. Menu Contact Dictionary Search.

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Study Findings. Metastatic Cancer Research. Intramural Research. Extramural Research. Cancer Research Workforce. Partners in Cancer Research. What Are Cancer Research Studies. Research Studies. Get Involved. Cancer Biology Research. Cancer Genomics Research. This is a mutation. It means that a gene has been damaged or lost or copied too many times. Mutations can happen by chance when a cell is dividing. Some mutations mean that the cell no longer understands its instructions.

It can start to grow out of control. There have to be about 6 different mutations before a normal cell turns into a cancer cell. What is cancer and how does it start? Cancer Research UK ! Content not working due to cookie settings.

View a transcript for the video about what is cancer and how does it start. It can take many years for a damaged cell to divide and grow and form a tumour big enough to cause symptoms or show up on a scan.

They can also be caused by the processes of life inside the cell. It also allows cancer cells to get into the blood and spread more easily to other parts of the body. There is a lot of research that is looking at using drugs that stop blood vessel growth called angiogenesis inhibitors , causing a tumour to stop growing and even shrink.

Cancer can also spread from where it first started to other parts of the body. This process is called metastasis. Cancer cells can metastasize when they break away from the tumour and travel to a new location in the body through the blood or lymphatic system. Most cancers have a tendency to spread to certain areas of the body. This has helped doctors develop staging systems that are used to classify cancers based on information about where the cancer is in the body and if it has spread from where it started.

Knowing how a cancer spreads and where a cancer may spread helps doctors predict how the cancer will grow. This also helps them plan treatment and give appropriate supportive care.

Cancer sometimes comes back after treatment. This is called a recurrence. Even if one cancer cell is left behind, it can grow and divide to become a new tumour. A new tumour can start to grow in the same area of the body where the cancer first started, or the cancer may have spread through the blood or lymphatic system to another part of the body, where it grows into a new tumour. This is why doctors sometimes use another treatment right after the first treatment, such as giving chemotherapy after surgery.

This is called adjuvant therapy. In the late stages of cancer, cells break through normal tissue boundaries and metastasize spread to new sites in the body. How Do Cancerous Changes Arise? Figure 1: Microevolution of a cancer cell. A series of mutations in a cell causes it to proliferate more than its immediate neighbors.

Figure 2. Figure 3. Figure Detail. Cancer is unchecked cell growth. Mutations in genes can cause cancer by accelerating cell division rates or inhibiting normal controls on the system, such as cell cycle arrest or programmed cell death. As a mass of cancerous cells grows, it can develop into a tumor. Cancer cells can also invade neighboring tissues and sometimes even break off and travel to other parts of the body, leading to the formation of new tumors at those sites.

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