Figure 2

Disease states and biomarkers. There are three stages during disease progression, i.e., a normal state, a pre-disease state and a disease state. A normal state is a relatively healthy stage including the chronic inflammation period or the stable period during which the disease is under control, whereas a pre-disease state is the limit of the normal state just before the critical transition into the disease state. And there are three types of biomarkers, i.e., traditional molecular biomarkers, network biomarkers, and newly developed dynamical network biomarkers (DNB). Both molecular and network biomarkers are static measurements on the disease and indicators on the disease state, whereas DNB are dynamical measurements on the pre-disease, thus providing the early-warning signals for the pre-disease state.