controlled study human human cell unclassified drug Humans 273 article 233 priority journal 188 nonhuman 187 Animals 152 animal cell 120 protein expression 111 metabolism 103 Article 98 mouse 94 Cell Line, Tumor 91 Mice 84 Cell Line 78 in vitro study 78 animal 66 female 66 cell proliferation 62 animal experiment 58 chemistry 58 signal transduction 53 animal model 52 apoptosis 51 protein protein interaction 51 in vivo study 49 tumor cell line 49 cell line 48