gene; genetic factor; genetic element
insulin-like growth factor; IGF
epidermal growth factor; EGF
zero divisor; null factor; nil factor
zero divisor; null factor; nil factor
lethal factor; lethal gene
natural moisturizing factor; NMF
tissue plasminogen activator; tPA; PLAT
macrophage migration inhibitory factor; MMIF
tumor necrosis factor (e.g. cachexin); tumour necrosis factor; TNF
vascular endothelial growth factor; VEGF