Oncoprotein expression in human breast epithelial cells transformed by high-LET radiation

. The knowledge of speci c genetic Purpose: The aim of the present work was to analyze the changes in tumorigenesis is critical to an understand-expression of oncoproteins that are frequently altered in breast ing of the natural history of breast tumors. These cancer with speci c phenotypic stages in the neoplastic process. changes may involve speci c genetic loci that directlyMaterials and methods: Expression of c-myc, c-jun, c-Ha-ras and contribute to one or more attributes of transforma-the tumor suppressor gene p53 oncoproteins were examined by immunohistochemical staining coupled with confocal microscopy tion, i.e. deregulated proliferation and invasion. in transformed and tumorigenic human breast epithelial cells Other changes may confer genetic instability, induced by high-LET a-particles (150 keV/mm). which increases the possibility of acquiring sub-Results: MCF-l0F cells, irradiated with single and double doses sequent speci c lesions relevant to tumorigenesis.of 60 cGy a-particles and subsequently treated with estrogen, Much still remains to be learned to understand theshowed gradual phenotypic changes including altered morpho-logy, increased cell proliferation relative to control, anchorage- key factors behind the evolution of breast cancer. It independent growth, invasive capabilities and tumorigenicity is accepted that the transformation of a normal cell in nude mice. MCF-10F cells irradiated with a second dose to one that is malignant can result from mutations of 60 cGy a-particles after estrogen treatment (60 cGy 1 in genes that encode key growth regulatory proteins.E/60 cGy 1 E) showed tumorigenicity both in SCID and nud