Our bodies are made up of more than a hundred million million ,,,, cells. Cancer starts with changes in one cell or a small group of cells. Usually, we have just the right number of each type of cell. This is because cells produce signals to control how much and how often the cells divide. If any of these signals are faulty or missing, cells might start to grow and multiply too much and form a lump called a tumour. A primary tumour is where the cancer starts. Some types of cancer, called leukaemia , start from blood cells.
They don't form solid tumours. Instead, the cancer cells build up in the blood and sometimes the bone marrow. For a cancer to start, certain changes take place within the genes of a cell or a group of cells. All cells have a control centre called a nucleus. Inside the nucleus are chromosomes made up of thousands of genes. Cells become cancer cells because of changes to their DNA deoxyribonucleic acid.
DNA is in every cell and it directs all its actions. In a normal cell, when DNA is damaged the cell either repairs the damage or dies. These new cells all have the same damaged DNA as the first cell does. Sometimes DNA damage may be caused by something obvious like cigarette smoking or sun exposure.
In most cases, the cancer cells form a tumor. Over time, the tumors can invade nearby normal tissue, crowd it out, or push it aside. Some cancers, like leukemia, rarely form tumors.
Instead, these cancer cells involve the blood and blood-forming organs and circulate through other tissues where they grow. Cancer cells often travel to other parts of the body where they can grow and form new tumors that crowd out normal tissue. The process of cancer spreading is called metastasis. For instance, colon cancer that has spread to the liver is called metastatic colon cancer, not liver cancer. Actively scan device characteristics for identification. Use precise geolocation data.
Select personalised content. Create a personalised content profile. Measure ad performance. Select basic ads. Create a personalised ads profile. Select personalised ads. Apply market research to generate audience insights. Measure content performance. Develop and improve products. List of Partners vendors. Cancer cells differ from normal cells in the body in many ways. Normal cells become cancerous when a series of mutations leads the cell to continue to grow and divide out of control, and, in a way, a cancer cell is a cell that has achieved a sort of immortality.
Also unlike normal cells that remain in the region where they began, cancer cells have the ability to both invade nearby tissues and spread to distant regions of the body. We will look at the process that leads to the development of a cancer cell, some of the ways in which cancer cells differ from normal cells, and why the body may not recognize cancer cells and destroy them as it does other "foreign" cells.
There are as many types of cancer cells as there are types of cancer. Of the hundred-plus types of cancer, most are named for the type of cancer cells in which it began. Carcinomas are cancers that arise in epithelial cells that line bodily cavities. Sarcomas are cancers that arise in mesenchymal cells in bones, muscles, blood vessels, and other tissues.
Leukemias, lymphomas, and myeloma are "blood-related cancers" that are arise from the bone marrow leukemias and multiple myelomas or the lymphoid tissues lymphomas and "fed" by nutrients in the bloodstream and lymph fluid such that they don't need to form tumors. Just as cancers may behave differently from one another, not all cancer cells behave the same way. Cancer cells appear through a series of genetic and epigenetic changes.
Some of these changes may be either inherited or more often, caused by carcinogens cancer-causing substances in our environment. In general, solid tumors, contain multiple mutations.
Interestingly, the metastatic process that is the main culprit for the high mortality of advanced cancers is thought to be caused mostly by epigenetic changes as no specific genetic alterations have been found in metastases. It also helps explain a genetic predisposition to cancer. A genetic predisposition does not mean you will get cancer, but, simplistically, if a few mutations are already in place, it will likely take fewer acquired mutations for a cell to become cancerous.
The process of normal cells becoming cancer often goes through stages in which the cell becomes progressively more abnormal appearing. These stages may include hyperplasia, dysplasia, and finally cancer.
You may also hear this described as differentiation. Early on a cell may look much like normal cells of that organ or tissue, but as progression occurs, the cell becomes increasingly undifferentiated.
This is, in fact, why sometimes the original source of cancer cannot be determined. A cancer cell can have thousands of mutations, but only a certain number of these genetic changes in cancer cells cause cancer to divide and grow. What is cancer? Diagram of cell division. Diagram of how cancer grows. Diagram of how cancer spreads. Where cancer can spread and staging. Why does cancer sometimes come back? Cure or remission. References American Society of Clinical Oncology.
What is Cancer? American Society of Clinical Oncology. What is Metastasis? Cancer Research UK. How Cancers Grow. How Cancer Starts. How Cancer Can Spread.
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