"Cancer" isn't a disease -- it's a term used to describe about 200 different types of diseases. All cancers have a few things in common, however. They're caused by mutations in our genetic material that make cells behave abnormally. They grow out of control and may destroy the cells around them or spread to other tissues. These mutations also keep the cells from dying according to their normal life cycle, which is part of why cancer cells can be so difficult to destroy.
When it comes to the development of cancer, two types of genes are involved: oncogenes and anti-oncogenes. Oncogenes are genes that have mutated within normal cells, causing them to start behaving like cancerous cells. Anti-oncogenes, or tumor suppressors, are genes that typically keep cells from becoming cancerous. When these genes mutate, this function is either compromised or completely suppressed.
At one time, a cancer diagnosis was a death sentence. Some forms of cancer are untreatable even now, but there are numerous treatment options for other types. Radiation, chemotherapy and surgery are some of the most well-known ways of treating cancer, but these have their limits -- as well as some pretty severe side effects. Finding a cure starts with learning more about exactly what causes those cells to mutate in the first place.
Until recently, it was thought that cancer was caused only by abnormalities within genes themselves. Now, researchers have discovered that some types of cancers are caused by changes in our epigenes -- a genetic code that sits on top of our DNA and affects the way that our genes express themselves. Epigenetic therapy may be able to treat some types of cancers, and it may also be able to prevent them from developing in the first place.