NASA Logo, External Link
Facebook icon, External Link to NASA STI page on Facebook Twitter icon, External Link to NASA STI on Twitter YouTube icon, External Link to NASA STI Channel on YouTube RSS icon, External Link to New NASA STI RSS Feed AddThis share icon
 

Record Details

Record 2 of 30
Chemoprevention of Radiation Induced Rat Mammary Neoplasms
Availability: Available in document 20000029456 on p. B-97 - B-98, or for help Contact the Information Desk
Author and Affiliation:
Huso, David L.(Johns Hopkins Univ., Oncology Center, Baltimore, MD United States)
Abstract: Radiations encountered in space include protons and heavy ions such as iron as well as their secondaries. The relative biological effect (RBE) of these ions is not known, particularly at the doses and dose-rates expected for planetary missions. Neutrons, are not particularly relevant to space travel, but have been found experimentally to have an increase in their RBE with decreasing dose. If a similar trend of increasing RBE with decreasing dose is present for heavy ions and protons during irradiation in space, the small doses received during space travel could potentially have substantial carcinogenic risk. Clearly more investigation of the effects of heavy ions and protons is needed before accurate risk assessment for prolonged travel in space can be done. One means to mitigate the increased risk of cancer due to radiation exposure in space is by developing effective countermeasures that can reduce the incidence of tumor development. Tamoxifen has recently been shown to be an effective chemopreventive agent in both animal models and humans for the prevention of mammary tumors. Tamoxifen is a unique drug, with a highly specific mechanism of action affecting a specific radiation-sensitive population of epithelial cells in the mammary gland. In human studies, the annual incidence of a primary tumor in the contralateral breast of women with previous breast cancer is about 8 per 1000, making them an exceedingly high-risk group for the development of breast cancer. In this high risk group, treated with tamoxifen, daily, for 2 years, the incidence of a new primary tumor in the contralateral breast was approximately one third of that noted in the non-tamoxifen treatment group. Tamoxifen antagonizes the action of estrogen by competing for the nuclear receptor complex thereby altering the association of the receptor complex and nuclear binding sites. Its effects in reducing the development of breast cancer could be accomplished by controlling clinically undetectable microcancers, arresting preneoplastic lesions, or correcting abnormal environments which predispose to high risk of malignant transformation.
Publication Date: Sep 30, 1999
Document ID:
20000029496
(Acquired Apr 14, 2000)
Subject Category: LIFE SCIENCES (GENERAL)
Document Type: Technical Report
Publication Information: SEE parent document record, "National Space Biomedical Research Institute"; p. B-97 - B-98
Financial Sponsor: NASA Johnson Space Center; Houston, TX United States
Organization Source: Johns Hopkins Univ.; Oncology Center; Baltimore, MD United States
Description: 2p; In English
Distribution Limits: Unclassified; Publicly available; Unlimited
Rights: No Copyright
NASA Terms: CANCER; CARCINOGENS; MAMMARY GLANDS; PREVENTION; RADIATION EFFECTS; RELATIVE BIOLOGICAL EFFECTIVENESS (RBE); TUMORS; NEOPLASMS; HEALTH PHYSICS; AEROSPACE MEDICINE; RATS; RADIATION DOSAGE; CELLS (BIOLOGY); PHYSIOLOGICAL EFFECTS
› Back to Top
Find Similar Records
NASA Logo, External Link
NASA Official: Gerald Steeman
Site Curator: STI Program
Last Modified: September 08, 2011
Contact Us