By: Michael Manion Page Views: 1282
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Any group of cells that have acted in this growth pattern and have become tissue are called a tumor. Not all tumors are cancerous. Some growths stop growing and are contained. These might never threaten life or health. These non-active tumors are called benign, meaning not harmful to life or health.

Most cancers fall into one of four categories. these are delineated according to the type of cells and tissue involved in the cancer.

  1. Epithelioma, or epithelial cancer, is also referred to as carcinomas meaning a malignancy made up of epithelial cells, these affect the skin of the body, mucous membranes, glands and internal organs. Epithelial tissue is composed of single layered cells that are closely arranged like that found on skin or membrane.
  2. Scirrhous, or hard cancer, is where the tumor has a hard consistency and is slow growing.
  3. Colloid is where the cancer cells are gelatinous.
  4. Encephaloid, also called medullary or soft cancer, is where the cellular structure predominates; the tumor is soft, fast growing and often ulcerated.

The four characteristics of cancer cells that differentiates them from normal cells are:

  1. Clonality, meaning that they originate from genetic changes in a single cell, which then multiplies to form a clone of malignant cells.
  2. Autonomy, in which their growth is not controlled by the normal biochemical and   physical activities of the body.
  3. Metastasis, when cancer cells are able to grow in the parts of the body other than their original site.
  4. Anaplasia, in which the growing cells do not develop into the normal cells similar to the one from which the clone arose.

There are also four basic stages of in the development of cancer cells that, once diagnosed, have different treatments depending on the area of the body. These stages have a variety of names depending upon the system used. One common system is called the TNM System in which T stands for tumor, N stands for degree of spread to lymph nodes, and M stands for the presence of metastasis. These then have several subcategories depending on the growth of the tumor. The basic four stages are described as follows:

  • Stage 1 or A: where the tumor is located on or in a contained area of the body. The cancer cells are present yet not forming a mass that can be detected or felt.
  • Stage 2 or B: the cancer is still confined to the same area and can be detected or felt and is growing.
  • Stage 3 or C: the cancer cells have spread to the surrounding area and are still growing.
  • Stage 4 or D: is considered late stage cancer, when the cancer cells have metastasized to other parts of the body.