MCF-7 human breast cancer cells are estrogen dependent for maximal in vitro growth and for tumor formation in nude mice, thus providing a useful model system to study mammary tumorigenesis. A clone of MCF-7 cells transfected with the v-rasH oncogene has been shown to form tumors in the absence of estradiol [Kasid et al., 1985, Science (Wash. DC), 228:725-728]. To extend this observation to more...
