Cancer may be as old as the start of humans. During the fifteenth century, cancer was referred to as a scirrus, or scar. In 1775, Sir Percivall Pott connected common occurrences of scrotal cancer among chimney sweeps with their frequent exposure to flue dust. Until the eighteenth century, Europeans treated cancer by cauterization and bloodletting. Although cancer research has been continuous for centuries, the most significant conclusions have been drawn in the twentieth century.
In 1950, Frank L. Horsfall, Jr. was concerned in discovering the causes of cancer. He thought that changes in the cell came from a change in DNA. Horsfall's finding that cancer is attributed to changes in the nucleic acid of cells provided a unifying concept for studying cancer. Approximately fifty years prior to Horsfall's observations, Peyton Rous was attracted in the physiology of cancer within animals, and found the first virus-induced cancer. This connective tissue cancer in chickens causes an increase of the liver and is deadly. Rous's original experiment included grafting sarcoma tumor cells from diseased hens into healthy hens. He noted that the healthy hens soon contracted the disease. Even filtered fluid extracts from diseased hens were contagious. Rous hypothesized that a virus may be the cause of the cancer.
Cancer is a group of diseases where cells grow abnormally and uncontrollable. In all living things, normal cells grow, reproduce, and die. Chemicals and reactions within the cell control these processes, which are directed by the cell’s DNA in the nucleus. In a cell that has been affected by cancer, the genetic material in the cell has been changed, and the genes which direct the cells’ actions are changed or mutated. These cancerous cells in someone’s body can grow and multiply and form a large mass of tissue called a tumor. These tumors may invade and kill non-cancerous cells. At times, cancerous cells can leave and break off from a tumor and enter the bloodstream, allowing the cell to travel to different destinations in the body and infecting other organs and tissues. This process is known as metastasis, and allows cancer to spread from an isolated tumor, to the entire body.
Most of the time, when people mention or use the word “cancer”, it is used to describe a malignant tumor. Malignant tumors are tumors that spread to different parts of your body and can end up harming you and are very aggressive. But, there are cases of tumors that are actually the complete opposite. Depending on the type of tumor, it could be limited to one part of the body and can be removed by surgery. These tumors are called benign tumors because they stay in one part of your body and cause no, or if so, very little harm. Normal cells change into a cancerous cell when the genetic material, which is deoxyribonucleic acid (DNA), or the cell is changed or mutated. There are various things that can cause these mutations and changes within a cell’s genetic material, such as viruses, medications, and synthetic carcinogens. Carcinogens are substances that cause a normal cell to change into a cancerous cell. When these substances disrupt a cell’s genetic material, it often brings about cancer. A tumor is the outcome of various gene mutations within a single cell. Prior to a tumor forming in