real time polymerase chain reaction Article 106 human 94 controlled study 89 Humans 85 genetics 72 female 55 male 53 adult 51 gene expression 50 metabolism 45 Female 44 nonhuman 43 Male 39 unclassified drug 39 major clinical study 35 middle aged 33 protein expression 33 upregulation 32 gene expression regulation 31 Middle Aged 30 human cell 29 Western blotting 28 human tissue 27 down regulation 25 Real-Time Polymerase Chain Reaction 24 pathology 24 case control study 23 Case-Control Studies 22 aged 20