Abstract on "how Cancer Arises"

Abstract on "How Cancer Arises"

Emily Asay

6 December 2011

Period 5

During the last 20 years, researchers have discovered how cancer develops. There are more than 100 forms of cancer and almost every tissue can become cancerous. All cells in the body live interdependently, regulation their neighbors' growth. However, cancer cells stop listening to the other cells' proliferation controls. Cancer cells can also metastasize into nearby tissues.

It is now known that a common ancestral cell is connected through descendants of the cells in a tumor. Also when there is an accumulation of mutations, malignant transformations can change protein amounts or activities. Proto-oncogenes stimulate proliferation, but tumor suppressor genes discourage proliferation.

Proto-oncogenes can become mutated and therefore become carcinogenic oncogenes, which cause multiplication or cells. When inactivated by mutations, tumor suppressor genes no longer stop unwanted cell growth. Different oncogenes are dangerous for different reasons. Some oncogenes energize growth-stimulatory pathways. Causing them to be constantly working when they should not be, while other oncogenes cause the over production on growth factors in cells. Those oncogenes can also cause growth in the same cells that produce them. There are also oncogenic versions of receptor genes, which release growth signals into the cell even when there are no growth factors present. Other oncogenes disrupt the signal cascade in the cell cytoplasm, like the ras family of oncogenes. Mutant ras genes continuously fire, even if growth factor receptors aren't telling them to. Myc genes are oncogenes that force cells to grow.

Cells must also be able to avoid or ignore "braking signals" from other "normal" cells for them to become cancerous. A substance called TGF-β can stop proliferation in carious cells, but cancerous cells become oblivious to it. Tumor suppressor proteins can also block the flow of signals, like the NF-1 gene that kills ras proteins. Cancer cells can regain some normality if a tumor suppressor gene is introduced into them. However, currently, this procedure is not proficient enough to be considered a cure.

More recent research has unearthed that the stimulatory and inhibitory pathways in the cell lead to a part of the cell nucleus known as the "cell cycle clock" which, in cancerous cells, does not function properly. Instead of having rest periods, like a normal cell, the cancerous cell will continue to grow and multiply.

Our body has many safeguards to protect against cancer such as depravation of growth stimulatory factors or giving antiprolific factors. Many cancer cells undermine these factors, and therefore there is a system that provokes