THE POTENTIAL INFLUENCE OF RADIATION-INDUCED MICROENVIRONMENTS IN NEOPLASTIC PROGRESSION

Ionizing radiation is a complete carcinogen, able both to initiate and promote neoplastic progression and is a known carcinogen of human and murine mammary gland. Tissue response to radiation is a composite of genetic damage, cell death and induction of new gene expression patter ns. Although DNA damage is believed to initiate carcinogenesis, the co ntribution of these other aspects of radiation response are beginning to be explored. Our studies demonstrate that radiation elicits rapid a nd persistent global alterations in the mammary gland microenvironment . We postulate that radiation-induced microenvironments may affect epi thelial cells neoplastic transformation by altering their number or su sceptibility. Alternatively, radiation induced microenvironments may e xert a selective force on initiated cells and/or be conducive to progr ession. A key impetus for these studies is the possibility that blocki ng these events could be a strategy to interrupt neoplastic progressio n.