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Cancer occurs when there is a loss in the control of the cell cycle. There are many controls of the cell cycle. There are many types of cancer. Up to 100 different genes are cancer related genes. These genes are found on all but two (22 and Y) human chromosomes.
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There are many controls of the cell cycle.
There are many types of cancer.
20,000 cancers were caused by excessive alcohol consumption.
abnormal cell shape
ignore normal tissue territory rules
increased uptake of sugar
increased anaerobic (without oxygen) respiration
production of specific antigen (e.g., carcino- embryonic hormone)
loss of contact inhibition and colony formation
(i.e., cells can lose contact with each other and move elsewhere to start colonies)
secrete DNA into the bloodstream
Oncogenes: Genes associated with the stimulation of cell division.
Cancers result from only one mutant allele of gene.
Tumor Suppressor Genes: Genes associated with inhibition of cell division. Cancers require both alleles of the gene to be altered.
DNA Repair Genes
Example: ATM ("ataxia telangiectasia mutated") gets its name from a human disease of that name, whose patients - among other things - are at increased risk of cancer. The ATM protein is also involved in detecting DNA damage and interrupting the cell cycle when damage is found.
Growth factor receptor
(tyrosine kinase activity)
Example: Deletions of the ligand binding domain of the epidermal growth factor receptor (EFGR) oncogene, located on human chromosome 7, result in continuous signal transduction by the epidermal growth factor receptor it encodes.
Transforming Viruses: The virus itself provides the proto-oncogene. The virus uses the host cellular machinery to cause cellular proliferation.
Retroviruses: A proto-oncogene gets captured by a retrovirus and made to be overexpressed. Causes cancer by capturing host-cells containing protooncogenes (inherent to the cell not the virus) and making the host over express them.
Mutation: Simple mutation of a proto-oncogene resulting in over expression.
The N-Myc gene has been found duplicated up to 1000 times in Retinoblastoma.
Chromosomal rearrangements/ Translocations: Chorionic Myelogenous Leukemia. Another method of activating proto-oncogenes.
The BRCA2 gene acts as a "caretaker," that is, it plays an important role in fixing DNA if it is broken -- a process that is constantly occurring as cells divide.
Another type of DNA repair is a form of nucleotide excision repair known as transcription-coupled repair.
Transcription-coupled repair, or TCR, occurs mostly in genes that are actively functioning. Without TCR, a cell has difficulty removing damage. Cells with a damaged TCR system can accumulate other mutations that lead to malignancy.
Hereditary Non-polyposis Colerectal
Multiple Endocrine Neoplasias
Familial Colon Cancer
Neurofibromatosis Type 1
Those who develop cancer from 30-40 years of age probably inherited a pre-disposition to cancer that allows the cells to develop cancerous conditions with fewer mutations.
In 1999, the U.S. biotechnology industry employed 153,000 people, up 48.5 percent from 1995, according to Ernst & Young.