Selenium-mediated inhibition of 7,12-dimethylbenz[a]anthracene-induced mouse mammary tumorigenesis

Area of Science:

• Oncology
• Nutritional Science
• Carcinogenesis

Background:

• Mammary tumorigenesis is a complex process influenced by chemical and viral factors.
• Preneoplastic lesions represent an early, critical stage in tumor development.
• Selenium's role in cancer prevention warrants further investigation.

Purpose of the Study:

• To investigate the effect of supplemental selenium on 7,12-dimethylbenz[a]anthracene (DMBA)-induced mammary tumorigenesis.
• To determine if selenium can inhibit both chemical- and viral-induced mammary tumors and preneoplastic lesions.
• To assess selenium's impact on the growth of established mammary tumors.

Main Methods:

• Administration of selenium (SeO2) in drinking water to several mouse strains.
• Induction of mammary tumors using the chemical carcinogen DMBA.
• Investigation of mammary tumour virus-induced hyperplasias.
• Monitoring of tumor formation, preneoplastic lesions, and established tumor growth.

Main Results:

• Selenium significantly inhibited mammary tumor formation in DMBA-treated mice across multiple strains.
• Selenium reduced the occurrence of DMBA-induced ductal hyperplasias and viral-induced alveolar hyperplasias.
• Selenium supplementation did not influence the growth rate of pre-existing mammary tumors.

Conclusions:

• Supplemental selenium demonstrates potent inhibitory effects on both chemical and viral-induced mouse mammary tumorigenesis.
• The development of preneoplastic lesions is highly sensitive to selenium-mediated inhibition, suggesting a preventative role.
• Selenium may be a valuable agent for preventing mammary cancer initiation.