MICROARRAY TECHNOLOGY In Cancer

1. MICROARRAY TECHNOLOGY In Cancer By: SE http://www.wormbook.org/chapters/www_germlinegenomics/germlinegenomicsfig1.jpg

2. Cancer • change in equilibrium between cell division, cell birth and cell death • Cancer cells grow out of control and don't die, spreading greatly (metastasic cancer) • Current therapies and anticancer do not differentiate between cancerous and normal cells • Not all cancers are the same; their gene expressions may differ

3. What is it? -Allows for the analysis of the simultaneous expression of thousands of genes • DNA molecules representing a lot of genes are placed in distinct spots on a microscopic slide • mRNA are the working copies of genes inside cells, are purified from cells of a particular type( i.e. tumor cell) •  mRNA are labeled by attaching a fluorescent dye • labeled mRNAs are placed onto a DNA microarray slide, and bind to their complementary DNA bases on the microarray, leaving a fluorescent mark • A special scanner is then used to measure the fluorescent areas on the microarray •  The degree of a fluorescent light that may be produced represents how actively expressed (or not) a gene may in a particular cell (tumor)

4. Classifications: • It is used to identify over expressed, normally, and deficiently expressed genes in specific cancers • Used to trace changes in active genes as normal cells is altered to malignant tumor cells • classification of types of cancers based on the patterns of gene activity in tumor cells Therapeutic Applications: • allowing for more effective treatments • Classifying types of cancer will allow for the designing of treatment strategies targeted to each specific type of cancer as well as the determing of treatment level of the specific cancers • used to tailor specific therapy according to the individual, prevent patients from having to undergo painful unsuccessful therapies

5. Diagnostic Applications • allow doctors to detect cancer earlier Prognostic Tools Prognosis:a medical opinion as to the likely course and outcome of a disease • used as prognostic tool; helping the individual response to cancer therapy • may be used to predict a patient’s response in certain number of years after therapy

6. Drug Applications • Should lead to new targets for drugs because of the high expression of a gene by a cancer suggesting that the cancer relies on that specific gene for its continuous survival • Used to identify genes with expression restricted to the specific (place) organ in the body, which could potentially act as appropriate tumor antigens • Defining those antigens that will provide production of antibodies which will destroy/inactivate specific tumor antigens

7. References • Afshari, C.A, Bushel, P.R., Hamadeh, H.K., & Lobenhofer, E. K. (2001). Progress in the Application of DNA Microarrays. Journal of Environmental Health Perspectives, 109, 881-888. Retrieved December 1, 2007 from EBSCO database.  • Aujame, L., Burdin, N., Dodet., & Vicari, M.(2002). Microarrays, immune responses, and vaccines. Annals of the New York Academy of Science, 975, 9- 18 217-231. • Goodison, S., Urquidi, V. (2007) Genomic signatures of breast cancer metastasis. 118,116-129. Retrieved November 7, 2007 from PubMed database.  • (2007). Microarray technology. Retrieved November 7, 2007 from the World Wide Web: http://www.genome.gov/glossary.cfm?key=microarray%20technology • Muhlrad, P. (2001). DNA microarray technology to identify genes controlling spermatogenesis. Retrieved November 5, 2007 from the World Wide Web: http://www.mcb.arizona.edu/wardlab/microarray.html • Nathan, D.G. (2007) The cancer treatment revolution. How smart drugs and other therapies are renewing our hope and changing the face of medicine. New Jersey: John Wiley & Sons, Inc. • Nelson, N.J., (2001). Microarrays have arrived: gene expression tool matures. [Electronic Version]. Journal of the National Cancer Institute, 93, 492-494. • Runowicz, C.D., Cherry, S.H., & Lange, D.P.(2004) The answer to cancer. USA: Rodale Inc.