source studies Blood 129 Cultured cells 28 Liver 27 Feces 24 Urine 13 Heart 13 Muscle 13 Lung 12 Brain 12 Bacterial cells 11 Plant 11 Cecum 8 Cells 7 Intestine 7 Macrophages 6 Kidney 6 Cerebrospinal fluid 5 Eye tissue 5 Adipose tissue 5 Seeds 4 Saliva 3 Leaf 3 Bacterial media 3 Fibroblast cells 2 Erythrocytes 2 Epithelial cells 2 Bone marrow 2 Tail 2 Ovarian cancer cells 2 Colon 2