Cancer Cells
"Cancer arises from mistimed or misplaced cell division or absence of normal apoptosis(Gaffin, p.152)." Apoptosis is a type of cell death that is a normal part of development. Cancer happens when cells begin to divide more rapidly than the cell from which theycame from, and continue doing so. The cells are able to grow due to mitosis, which is aform of cell division that enables an organism to grow by adding cells. A cancerous cell obtains oxygen and nutrients from surrounding blood vessels bydiffusion across its membrane, in the same way as normal cells. As the tumor enlarges, itsinner cells are starved of nutrients. Enlarging tumors use two methods of acquiringnutrients, by invading existing blood vessels and by angiogenesis. Angiogenesis is theprocess by which a tumor stimulates new blood vessels to form. Cancer inducedangiogenesis builds the cancer cells own blood supply. Since proteins control the cell cycle, and genes encode proteins, genes play a majorrole in causing cancer. There are two major classes of genes that contribute to causingcancer; the oncogenes and the tumor suppressor genes. Oncogenes are versions of genes that normally trigger cell division, but they are
Tumors form because of the lack of contact inhibition. A cancers growth rate depends upon the type of cell affected. They are very cautious when doing any type of surgery orbiopsy because of the knowledge they have on how cancer can spread. The liver is the particularly common site sinceit receives blood from the heart and the intestines. Some of these routes aremetastasis, local invasion, and implantation or inoculation. Tumors often form in epithelialtissue, which covers the body and lines body cavities and organs. This type of cancer is very curable, because once the wide area of healthytissue surrounding the cancer is removed the doctors don't have to worry about itspreading; this takes place in the metastasis process. Inactivation or removal of thetumor suppressor gene can cause cancer. Even the speediest cancer cells,which complete a cell cycle every 18-24 hours, do not divide as often as some normalhuman embryo cells. " Cancer can also spread through what is known as local invasion. The reason for this is that your genes will sufferdamage just from day to day living. As expressedthroughout our research you can easily see how powerful cancer really is, by theirdetermined nature to strive for survival. Meanwhile, as a cancer spreads, it mutates, and the treatment that shrankthe original tumor may have no effect on this secondary growth (Anderson, p. Cancer cells have the ability tosqueeze into or invade any available space because of their surface structures.
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