animal model nonhuman 56 female 54 mouse 54 Animals 52 animal experiment 50 Female 48 Mice 48 controlled study 48 article 44 breast cancer 42 animal cell 40 Mice, Inbred BALB C 36 priority journal 36 human 34 protein expression 34 Humans 32 animal tissue 32 Breast Neoplasms 26 human cell 26 Receptors, Progesterone 24 animal 24 cell proliferation 24 metabolism 24 progesterone receptor 24 Cell Line, Tumor 22 cancer growth 20 in vivo study 20 tumor growth 20 unclassified drug 20