10 Facts About Cancer Cells

ancer cells are abnormal cells that reproduce rapidly, maintaining their ability to replicate and grow. This unchecked cell growth results in the development of masses of tissue or tumors. The tumors continue to grow and some, known as malignant tumors, can spread from one location to another. Cancer cells differ from normal cells in a number or ways. Cancer cells don't experience biological aging, maintain their ability to divide, and do not respond to self-termination signals. Below are ten interesting facts about cancer cells that may surprise you.

1. There Are over 100 Types of Cancer

There are many different types of cancer and these cancers may develop in any type of body cell. Cancer types are typically named for the organ, tissue, or cells in which they develop. The most common type of cancer is carcinoma or cancer of the skin. Carcinomas develop in epithelial tissue, which covers the outside of the body and lines organs, vessels, and cavities. Sarcomas form in muscle, bone, and soft connective tissues including adipose, blood vessels, lymph vessels, tendons, and ligaments. Leukemia is cancer that originates in bone marrow cells that form white blood cells. Lymphoma develops in white blood cells called lymphocytes. This type of cancer affects ​B cells and T cells.

2. Some Viruses Produce Cancer Cells

Cancer cell development may result from a number of factors including exposure to chemicals, radiation, ultraviolet light, and chromosome replication errors. In addition, viruses also have the ability to cause cancer by altering genes. Cancer virusesare estimated to cause 15 to 20% of all cancers. These viruses change cells by integrating their genetic material with the host cell's DNA. The viral genes regulate cell development, giving the cell the ability to undergo abnormal new growth. The Epstein-Barr virus has been linked to Burkitt's lymphoma, the hepatitis B viruscan cause liver cancer, and human papilloma viruses can cause cervical cancer.

3. About One-third of All Cancer Cases Are Preventable

According to the World Health Organization, about 30% of all cancer cases are preventable. It has been estimated that only 5-10% of all cancers are attributed to hereditary gene defect. The rest are related to environmental pollutants, infections, and lifestyle choices (smoking, poor diet, and physical inactivity). The single greatest preventable risk factor for cancer development globally is smoking and tobacco use. About 70% of lung cancer cases are attributed to smoking.

4. Cancer Cells Crave Sugar

Cancer cells use much more glucose to grow than normal cells use. Glucose is a simple sugar required for the production of energy through cellular respiration. Cancer cells use sugar at a high rate to continue to divide. These cells do not obtain their energy solely through glycolysis, the process of "splitting sugars" to produce energy. Tumor cell mitochondria supply the energy needed to promote abnormal growth associated with cancer cells. Mitochondria provide an amplified energy source that also makes tumor cells more resistant to chemotherapy.

5. Cancer Cells Hide in the Body

Cancer cells can avoid the body's immune system by hiding among healthy cells. For example, some tumors secrete a protein that is also secreted by lymph nodes. The protein allows the tumor to transform its outer layer into something that resembles lymph tissue. These tumors appear as healthy tissue and not cancerous tissue. As a result, immune cells do not detect the tumor as a harmful substance and it is allowed to grow and spread unchecked in the body. Other cancer cells avoid chemotherapy drugs by hiding in compartments in the body. Some leukemia cells avoid treatment by taking cover in compartments in bone.

6. Cancer Cells Morph and Change Shape

Cancer cells undergo changes to avoid immune system defenses, as well as to guard against radiation and chemotherapy treatment. Cancerous epithelial cells, for example, go from resembling healthy cells with defined shapes to resembling loose connective tissue. Scientists relate this process to that of a snake that sheds its skin. The ability to change shape has been attributed to the inactivation of molecular switches called microRNAs. These small regulatory RNA molecules have the ability to regulate gene expression. When certain microRNAs become inactivated, tumor cells gain the ability to change shape.

7. Cancer Cells Divide Uncontrollably and Produce Extra Daughter Cells

Cancer cells can have gene mutations or chromosome mutations that affect the reproductive properties of the cells. A normal cell dividing by mitosis produces two daughter cells. Cancer cells, however, can divide into three or more daughter cells. The newly developed cancer cells may either lose or gain extra chromosomes during division. Most malignant tumors have cells that have lost chromosomes.

8. Cancer Cells Need Blood Vessels to Survive

One of the telltale signs of cancer is the rapid increase of new blood vessel formation known as angiogenesis. Tumors need the nutrients provided by blood vessels to grow. Blood vessel endothelium is responsible for both normal angiogenesis and tumor angiogenesis. Cancer cells send signals to nearby healthy cells influencing them to develop new blood vessels that supply the cancer cells. Studies have shown that when new blood vessel formation is prevented, tumors stop growing.

9. Cancer Cells Can Spread From One Area to Another

Cancer cells can metastasize or spread from one location to another through the bloodstream or lymphatic system. Cancer cells activate receptors in blood vessels that allow them to exit blood circulation and spread to tissues and organs. The cancer cells release chemical messengers called chemokines that induce an immune response and enable them to pass through blood vessels into the surrounding tissue.

10. Cancer Cells Avoid Programmed Cell Death

When normal cells experience DNA damage, tumor suppressor proteins are released that cause the cells to undergo programmed cell death or apoptosis. Due to gene mutation, cancer cells lose the ability to detect DNA damage and therefore the ability to self-destruct.

_Sources:

• _{Cancer Prevention. World Health Organization. Accessed 05/15/15. (http://www.who.int/cancer/prevention/en/)}
• _{What Is Cancer? National Cancer Institute. Updated 02/09/15. (http://www.cancer.gov/about-cancer/what-is-cancer)}
• _{Ecole Polytechnique Fédérale de Lausanne. "Tumors hide out from the immune system by mimicking lymph nodes." ScienceDaily. ScienceDaily, 26 March 2010. (www.sciencedaily.com/releases/2010/03/100325143042.htm)}
• _{IDIBELL-Bellvitge Biomedical Research Institute. "Why do cancer cells change their appearance?." ScienceDaily. ScienceDaily, 12 October 2011. (www.sciencedaily.com/releases/2011/09/110902110144.htm)}