Cancer is one of the most common diseases today, affecting approximately one in three people in the United States. The body is made up of trillions of cells, and cells normally die when they become abnormal. When the cells are not dying when they should, however, they continue to grow, crowding out normal cells and making the body work harder to repair them. Fortunately, the main cause of cancer isn’t a particular cause, but rather an accumulation of factors.
One of the most common causes of cancer is genetics. Mutations in cancer cells cause the cells to divide uncontrollably and to resist the body’s repair systems. This makes them resistant to processes designed to get rid of old cells, such as cell death. These changes make cancer cells more likely to spread through the body. But not all genetic changes in cancer cells cause the disease. In fact, some of the most common ones are in tumor suppressor genes and proto-oncogenes.
The transformation of a normal cell into a cancer cell is a series of errors that compound over time. Each initial error in a normal cell’s DNA replication leads to a more severe error and the cells then escape more controls. While the survival of the fittest may be desirable, this scenario is not desirable for the body. Instead, evolution works against the body’s design. This ongoing process, called clonal evolution, propels the progression of cancer cells towards more advanced stages. This causes tumors to be heterogeneous, which complicates treatment strategies.
The progression of cancer is determined by the genetic mutations in the cancer cells. The genes in normal cells, called chromatin, are responsible for the evolution of cancer cells. They evolve faster than normal chromosomes, giving them an advantage in clonal selection. The mutations in cancer cells are caused by DNA repair genes. This explains why a tumor cannot be completely destroyed through surgery. The most common tumors are those that have many mutations.
The emergence of cancer cells is caused by mutations in their DNA. The mutations enable the cells to divide uncontrollably and to evade the immune system’s repair mechanisms. The cancer cells also lack resistance to other processes that the body uses to deal with old cells. This can lead to the formation of a tumor. But there is a solution. Most cancers are a result of multiple mutations in these two types of cells.
In cell cultures, cancer cells exhibit the uncontrolled growth of normal cells. While normal cells display a density-dependent inhibition of cell proliferation, most cancer cells lack this ability and are unable to withstand this limit. They grow rapidly until they reach a certain density and stop growing. Once reached, the cells become “quiescent,” arresting in the G-stage of the cell cycle. It is important to note that while cancer cells lack this quality, they are still prone to other types of mutations.