These cells (which contain cancer) are able to penetrate other muscles or body parts by growing inside them. They can also penetrate other tissues by inserting themselves into distant places in the body via “metastasis”. Metastasis is a process that occurs when cancer cells move through the bloodstream or lymphatic system. When this happens, a person's cancer can spread within their body. Cancer can affect anyone at any age. Most types of cancer are more likely to affect people as they age. This is because a person's DNA ages. Their DNA could become damaged, which has happened in the past and could get worse. A type of cancer that is more common in young people, rather than older people, is testicular cancer (testicular cancer). There is no cure for cancer. It can only be cured if all cancer cells are cut out or killed on the spot. This means that the earlier the cancer is treated, the better the chance of recovery (because the cancer cells may not have had enough time to copy themselves and spread to such an extent that the person cannot be cured). There are several types of treatments used to try to kill cancer cells. These treatments are radiation therapy (which uses radiation to kill cancer cells); chemotherapy (which uses powerful drugs to kill cancer cells); and biological therapy. In some cases, at least part of the tumor can be removed surgically. But this is not the end of the treatment. After surgery, sufferers may need radiotherapy or chemotherapy to stop the tumor from growing again. A big problem in cancer treatment is that most factors that kill cancer cells also kill normal, healthy cells. This is why people who undergo chemotherapy often lose their hair and shed... middle of paper... things that are known to cause many different types of cancer. For example, tobacco use (smoking or smokeless) can cause many types of cancer, such as lung, mouth, tongue, and throat cancers. Other things known to cause cancer or make a person more at risk of getting cancer include not being protected from much sunlight, radiation (including x-rays in large or numerous quantities, chemicals used in construction and work, high-fat or low-fiber diets; dirty air and water, consumption of very few fruits and vegetables; not enough physical activity, excessive consumption of alcohol and some chemicals commonly used in the home. Some cancers can be caused even from viruses. Even if a person is exposed to one of these possible causes of cancer, it does not mean that he will automatically get sick. Many people who do these things do not get cancer, but some do..