controlled study human 290 human cell priority journal article 220 Humans 213 nonhuman 121 Animals 101 protein expression 100 animal cell 88 unclassified drug 87 female 79 Female 70 Article 64 signal transduction 63 mouse 61 metabolism 60 Mice 58 cell proliferation 58 male 56 in vitro study 51 Male 50 animal experiment 46 Cell Line 45 Cell Line, Tumor 45 protein function 42 apoptosis 41 Signal Transduction 36 Western blotting 35 animal model 35