The tumor is comprised of abnormal cells. These abnormal cells then take over the organ that they begin in and are also named after it. For example, if a single cell becomes abnormal in the liver, and then forms a cancerous tumor, it would be malignant, and would be called liver cancer. Although, not all cancers form tumors. Also, abnormal cells can spread to other areas of the body besides where they originally started (www.cancer.gov).
The number of genes varies by different tumors and locations in the body. Invasive cancer begins when the genetic changes allow the tumor to invade and take over certain tissues, and shed cells into the blood (lymph). When this occurs, the mass is then considered to be malignant. The rene... ... middle of paper ... ...s- which we would now consider immunotherapies because they aimed to attack disease with the body’s own defenses- brought about complete tumor regressions in some individuals. But they were not broadly accepted, because the results were unpredictable (What You Need To Know About Cancer, 101).
Cancer starts when cells in a part of the body start to grow out of control. Cancer cell growth is different from normal cell growth. Instead of dying, cancer cells continue to grow and form new, abnormal cells. Cancer cells can also invade (grow into) other tissues, something that normal cells cannot do. Growing out of control and invading other tissues are what makes a cell a cancer cell.
There are two different types of cancer tumors. Some tumors are benign and other tumors are malignant. Benign tumors look similar to the tissues that they came from and develop slowly. The tumor remains in the same area that the tumor originated in. Malignant tumors are formed from cells that do not resemble the tissue that they came from.
Cancer is considered a genetic disorder. Studies have identified a small number of genes that must be mutated to bring about development of cancer or maintain the growth of malignant cells (Klug, 1996). Two main properties of cancer are uncontrollable cell division and the ability to spread or metastasize. Both are results of genetic alterations. Mutations in the cells that lead to certain forms of cancer, can be identified as inherited in some families.
Proto-oncogenes are those genes that control normal but essential cell processes that keep cell growth and death in check. Two important categories are apoptosis genes, which regulate cell death, and tumor suppressor genes, which decrease cell propagation 1 . If these genes were mutated to the point where they cannot produce a functioning protein, cell division would continue far past what it was supposed to and unhealthy cells would be allowed to live and continue to multiply. This is what creates a malignant tumor. Certain conditions in the body can also promote the growth of cancer cells.
However, a malignant tumor is cancer. A malignant tumor can also "crowd out " the healthy cells around it, but in addition to thatt it can spread to other parts of the body and take over the healthy cells in different areas of the body. Skin cancer is a disease in which cancer cells are found in the outer layers of skin. The skin has two main layers and several kinds of cells. The top layer is the epidermis and it is the layer that is shed most frequently.
Sometimes malignant tumors will invade a healthy cell to make it an abnormal cancer cell. This is called metastasis. This occurs when the cancer cells leave the tumor through the bloodstream or lymphatic system to other parts of the body. When the cells come to rest the multiply and form a new tumor. This spreading is what makes cancer especially dangerous.
Benign tumors are not cancerous, but can still instill problems. Benign tumors can become malignant, or cancerous, after a period of time. Malignant tumors are the ones that are cancerous from the very beginning. This ... ... middle of paper ... ...emo that is given. Some cycles are more intense than others.
ETIOLOGY OF CANCER Introduction Cancer is a term used for a large group of diseases that arises from a single cell which has undergone abnormal changes. It usually spreads through blood and lymph. In a normal cell, there is a proper mechanism that prevents cell overgrowth and the invasion of other tissues. Whereas, in cancer cells this process is disturbed. These abnormal cancer cells divide and grow in the presence of signals that normally inhibits or control cell proliferation.