Cancer

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.

These changes can alter the metabolism and re-engineer the process facilitating the rapid growth and survival of cancer cells through the RAS and mTORC1 pathway. (Rob A. Cairns. et al. 2001 and Chi V Dang. 2012) Lipid, protein... ... middle of paper ... ... complex mechanisms of each type of cancer, there may be different in details and may have to find out more.

The most common cancer cells are present in rearrangements and chromosomal aberrations. The cancer cells will development from multistep process such as mutation and the cells selection for progressively increasing for proliferation, invasion, survival and metastasis process. The cancer cells origins from a single Primary tumor, arising in an identified organ and presumed to be derived by cell division that has undergone some heritable changes to outgrow its neighbors (Bruce. Alberts, 2002). The abnormal cells will proliferation then leads to increased growth the cells will derived tumor cells.

This causes the surviving cells to multiply and create a whole new colony resistant to that specific drug. Symptoms and Treatments. Cancer signs and symptoms are quite different and depend on where is the cancer located, how deep it has spread, and what is size of the tumor is. Some cancers can be either felt or seen through the skin , such as, a lump on the external lining can be an indicator of cancer in those locations. Other cancer types have signs that have a less physical appearance.

There are many different types of cancer and many different causes for the the disease. Most cancers are because of a genetic mutation. The most common type occur when a cell is dividing. Proto-oncogenes, which are alleles in a normal cells, mutate to form oncogenes. These oncogenes cause cancer because they do not allow the cells to self destruct or become epistatic.

Some of them grow quickly & others grow slowly. The rate of progression of tumor is governed both by mutagenic agents (tumor initiators) and by non mutagenic agents (tumor promoters) that effect gene expression, stimulate cell proliferation and alter the ecological balance of mutant and non mutant cells. The cancer cells frequently move and break from site of the mass or tumor and enter into the bloodstream thereby spreading the disease to other parts of the body and this process is called metastasis (Steward & Kliehues, 2003). Cancer is often defined as a disease that involves changes or mutations in the cell genome. These changes (DNA mutations) produce proteins that disrupt the delicate cellular balance between cell division and quiescence; resulting in cells that keep dividing to form cancers (Hejmadi 2010).

Cancer cells within the tumor will then use the newly formed blood vessels as a port to metastasize to other localities. Including the drugs for colon cancer, a growing number of anticancer agents have been shown to inhibit hypoxia inducible factor (HIF) gene activity. For many of these, the mechanism of action has been established and involves a reduction in HIF-1 mRNA or protein levels by suppressing the HIF gene expression (Semenza, 2007). Hypoxia is the principal trigger to stimulate VEGF gene transcription and subsequently to angiogenesis. VEGF is responsible triggering the various steps in the angiogenesis cascade such as proliferation, migration and cell survival.

It is suggested that neural apoptosis maybe through the intrinsic pathway or extrinsic. The accumulation of dysfunctional mitochondria because of inefficient removal of damaged mitochondria (mitophagy) causes an increase in free radical leakiness and the cycle of oxidative damage to the bio molecules and thus helping in apoptosis. [3]

When unnoticed or uncontrolled, these tumors can develop aggressively and quickly causing major disruption in vital organs and tissues needed for the person’s survival and growth. Tumor development occurs in stages. The creation of a malignant (or very infectious) tumor in epithelial tissues (tissues that line the cavities and surfaces of structures throughout the body, which form many glands) is the most common of malignancies, which are called carcinomas. The tumor is a result of the mass formed by the cancer cells, which can also be considered a mutation in any number of genes. The number of genes varies by different tumors and locations in the body.

To understand cancer, it's helpful to know what happens when normal cells become cancer cells. The body is made up of many types of cells. These cells grow and divide in a controlled way to produce more cells as they are needed to keep the body healthy. When cells become old or damaged, they die and are replaced with new cells. However, sometimes this orderly process goes wrong.