Verified Document

Cancer Epidemiology Term Paper

HuGE Cancer Epidemiology HuGE Study

Masson, L. Sharp, S.C. Cotton and J. Little. Cytochrome P-450 1A1 Gene Polymorphisms and Risk of Breast Cancer: A HuGE Review. Am. J. Epidemiol. (15 May 2005) 161 (10): 901-915.

Category of HuGE Information

The types of information available from the article:

Prevalence of gene variant

Gene-disease association

Gene-environment interaction

Gene-gene interaction

Cytochrome P-450 (CYP) 1A1 plays a key role in phase I metabolism of polycyclic aromatic hydrocarbons and in estrogen metabolism. It is expressed predominantly in extrahepatic tissues, including the breast. Four CYP1A1 gene polymorphisms (3801T-C, Ile462Val, 3205T-C, and Thr461Asp) have been studied in relation to breast cancer. The 3801C variant is more common than the Val variant. Both variants occur more frequently in Asians than in White populations. The 3205T-C polymorphism has been observed in African-Americans only. Little data are available on the geographic/ethnic distribution of the Thr461Asp polymorphism. The functional significance of the polymorphisms is unclear. In 17 studies, no consistent association between breast cancer and CYP1A1 genotype was found. Meta-analysis found no significant risk for the genotypes 1) 3801C/C (relative risk (RR) = 0.97, 95% confidence interval (CI): 0.52, 1.80) or 3801T/C (RR = 0.91, 95% CI: 0.70, 1.19) versus 3801T/T, 2) Val/Val (RR = 1.04, 95% CI: 0.63, 1.74) or Ile/Val (RR = 0.92, 95% CI: 0.76, 1.10) versus Ile/Ile, or 3) Asp/Asp (RR = 0.95, 95% CI: 0.20, 4.49) or Thr/Asp (RR = 1.12, 95% CI: 0.87, 1.43) versus Thr/Thr. Future studies should explore possible interactions between CYP1A1 and sources of polycyclic aromatic hydrocarbons, markers of estrogen exposure, other lifestyle factors influencing hormonal levels, and other genes involved in polycyclic aromatic hydrocarbon metabolism or hormonal biosynthesis.

Gene:

Gene Name, Chromosome location, and gene product/function:

Cytochrome P-450 (CYP) 1A1 is a key enzyme in phase I bioactivation...

It contributes to aryl hydrocarbon hydroxylase activity, catalyzing the first step in the metabolism of a number of polycyclic aromatic hydrocarbons (PAHs), such as the tobacco carcinogen benzo[a]pyrene, to their ultimate DNA-binding forms. It is also involved in estrogen metabolism, catalyzing the hydroxylation of 17?-estradiol at the C-2 position.
The CYP1A1 gene, located at 15q22-q24, comprises seven exons and six introns and spans 5,810 base pairs. In humans, CYP1A1 is under the regulatory control of the aryl hydrocarbon receptor, a transcription factor that regulates gene expression.

CYP1A1 expression occurs predominantly in extrahepatic tissue. CYP1A1 messenger RNA has been detected in normal and cancerous breast tissue and can be induced in human-breast-derived cell lines.

Alleles: CYP1 family:

CYP1A1; CYP1A2; CYP1B1; CYP2 family: CYP2A6; CYP2A13; CYP2B6; CYP2C8; CYP2C9; CYP2C19; CYP2D6; CYP2E1; CYP2F1; CYP2J2; CYP2R1; CYP2S1; CYP2W1

CYP3 family:

CYP3A4; CYP3A5; CYP3A7; CYP3A43

CYP4 family:

CYP4A11; CYP4A22; CYP4B1; CYP4F2

CYP>4 families:

CYP5A1

CYP8A1

CYP19A1

CYP21A2

CYP26A1

OMIM #: 108330

Environmental Factors:

1. PAHs (polyaromatic hydrocarbons)

2. Tobacco smoke

3. Estrogen

4. Fried foods

5. Alcohol

6. PCBs (polychlorinated biphenols)

Health Outcomes:

1. Incidence of breast cancer risk in association with C-P450 mutations

2. Determine variants of C-P450 polymorphisms in specific ethnic populations

3. Determine gene-gene and gene-environment interactions for CP450 alleles and breast cancer.

Study design

This is a descriptive, cross-sectional study.

Assessment of environmental factors:

Environmental factor: Smoking

Exposure assessment and definition: genotype-smoking interactions light smokers (

Cite this Document:
Copy Bibliography Citation

Related Documents

Cancer the Medical Name for Cancer Is
Words: 1628 Length: 5 Document Type: Essay

Cancer The medical name for cancer is malignant neoplasm. There are approximately forty different types of cancers, including a few varieties of leukemia and lymphoma. Cancer is a disease that has increased in frequencies in countries such as the United States of America during the latter part of the 20th century and into the 21st. In fact, according to statistics gathered by leading clinics in the U.S.A., cancer is the second

Cancer Is a Class of
Words: 1164 Length: 4 Document Type: Essay

, about 700,000 deaths per annum); Bone (Leukemia) (cancer of the blood or bone marrow and characterized by an abnormal proliferation of white blood cells); Lymphoma (Lymphatic) (cancer that begins in the lymphocytes of the immune system then presents as a solid tumor, many types, many treatments); Brain (Neuro/Nervous) (abnormal growth of cells within the brain, can be cancerous or non-cancerous, 50,000 U.S. cases per annum, 13,000 deaths per annum);

Lung Cancer As Compared to
Words: 1374 Length: 3 Document Type: Research Paper

Provide a rationale and support for your recommendations. Radon: A story of radon-related lung cancer in Minnesota was publicized to thousands of viewers via media followed by the Minnesota-legislature passing a law that required radon-resistant construction in all new homes. Similar legislation was passed in Illinois. Pennsylvania can adopt a similar stance preceding the legislation with widespread publicity in order to educate the public about the matter. Steps should also be taken

Breast Cancer in Malaysia Breast Cancer Has
Words: 3180 Length: 11 Document Type: Essay

Breast Cancer in Malaysia Breast cancer has turned out to be one of the most common cancers in women in almost every part of the world. Nonetheless, there is a noticeable geographical difference in the incidence and also the stage of presentation. It has ben documented to be uppermost in North Europe and North America, in-between in Mediterranean nations and South America, and not high at all in Asia and Africa

Pathophysiology of Cervical Cancer Every
Words: 2211 Length: 6 Document Type: Research Paper

2008). Indeed better screening is necessary due to the number of false-negatives from women with precancerous lesions among the most frequent reasons of medical malpractice in the United States (Steben, M. et al. 2007). In the case of having a tissue sample to be tested, early stage cervical cancer can be differentiated from healthy cervical tissue by gene expression profile due to comparisons done with healthy and lymph node metastatic

Risk Factors for Lung Cancer
Words: 804 Length: 2 Document Type: Research Paper

Lung Cancer Risk Factors Lung cancer is the most commonly diagnosed cancer in the world, accounting for 12.7% of all new cancers cases annually (McErlean and Ginsberg, 2011, p. 173). Lung cancer is also the most lethal, killing more people each year (18.2%) that any other type of cancer (Molina, Yang, Cassivi, Schild, and Adjei, 2008, p. 584; Brennan, Hainaut, and Boffetta, 2011, p. 399). There are very large geographical differences

Sign Up for Unlimited Study Help

Our semester plans gives you unlimited, unrestricted access to our entire library of resources —writing tools, guides, example essays, tutorials, class notes, and more.

Get Started Now