Animal experimental systems are particularly useful for the study of human breast cancer.1,2 An ideal model should be easy to use, closely mimicking human physiopathology and has a stable tumor morbidity. The cell line MA891 was established from a spontan Animal experimental systems are particularly useful for the study of human breast cancer.1,2 An ideal model should be easy to use, closely mimicking human physiopathology and has a stable tumor morbidity. The cell line MA891 was established from a spontan