What is cancer?Normally, genes control cells and tell them when to die off so new cells can divide and take their place. However, genetic mutations can alter those genes, causing things to go very, very wrong. Cells may not respond to signals telling them to stop or continue growing. When they ignore these signals and grow too fast, they become cancerous. Cancerous cells can then proceed on to metastasize to other parts of the body. If not caught early on, it can be very difficult to treat.
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What is the cell cycle?
The cell cycle is the series of events starting in cell that leads to its division and death. Through mitosis, a cell will replicate its genetic material before splitting into two identical daughter cells. This is a simple way to explain how people grow. As random as it seems, it is not. A series of complex mechanisms signal when to go through each stage. If any errors are found, they can be corrected. If mistakes cannot be fixed, a cell can even be told to commit suicide, a process known as apoptosis where the cell naturally shuts down. However, if a genetic mutation disrupts these mechanisms, cells can divide at fast rates uncontrolled. They will not pause or undergo apoptosis. These cells are now cancerous.
What do cancerous cells do?
The growth of cancerous cells will form clumps of tissue, called tumors. The cells in these unwanted tumors act very similar to normal cells. Blood vessels will grow through them and supply nutrients, as well as remove waste. The immune system will not recognize them as foreign and attack them. However, they don't go through normal cell death processes, and serve no distinct function. Cancerous cells are harmful because they leech nutrients off of the healthy cells that need it. Tumors formed from solid tissues will usually be solid, and can sometimes be felt. Tumors that form in the blood may not always be solid, as blood is a type of tissue.
It is important to note that not all tumors are cancerous. A tumor is simply a mass of too many cells. It can be benign, which means it will not spread and can be easily treated. Or it can be malignant, which is the cancerous type. They metastasize, are resistant to treatment, and even after being removed, can sometimes come back again.
It is important to note that not all tumors are cancerous. A tumor is simply a mass of too many cells. It can be benign, which means it will not spread and can be easily treated. Or it can be malignant, which is the cancerous type. They metastasize, are resistant to treatment, and even after being removed, can sometimes come back again.
What is metastasis?
When cancers metastasize, they spread from one tissue to another. It happens when cancerous cells manage to enter other parts of the body, and affect tissues there. Before successfully spreading and staying at a location, it must meet several requirements. Cells have to be able to break away and travel in the blood stream or lymph system. They must be able to take root at an organ, thrive there, and avoid the immune system. Any cancer can metastasize, and can spread to anywhere in the body, the most common locations being the liver, bones, and lungs. Metastasized cancer bears resemblance to the cancerous cells it originated from, with similar proteins and chromosome changes. Symptoms include aching bones, headaches, and yellowing of the skin. It is known as stage IV cancer, and 90% of cancer deaths occur at this point.
Metastasized cancers will retain the name of the tissue in which they spread from. For example, if breast cancer spreads to the bone, it is still considered breast cancer. They are also treated that way too. Breast cancer will still be treated as breast cancer no matter if it has metastasized or not.
Metastasized cancers will retain the name of the tissue in which they spread from. For example, if breast cancer spreads to the bone, it is still considered breast cancer. They are also treated that way too. Breast cancer will still be treated as breast cancer no matter if it has metastasized or not.
More random facts
- There are over a hundred types of cancer, with many different causes and symptoms
- There are different ways to stage cancer. You may have heard of stage I, II, III, or IV. It starts with stage 0, in which the cancer has not spread at all, to stage IV, in which the cancer has metastasized greatly.
- Although cancer is affected by genetics, only 5%-10% cancers are entirely caused by genes. The rest are due to a combination of poor diet, consumption of alcohol and tobacco, and other environmental factors. Even a few pathogens have the ability to cause cancer.
- Onco- means relating to tumors. Therefore, oncology is the study of cancer and tumors.
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More Information
ACS - What is Cancer?
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NCI - What is Cancer?
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