Simonsen et al. used cerebrospinal fluid to detect candidate biomarkers, which are capable to differentiate between patients with stable mild cognitive impairment (MCI) and those who will progress to Alzheimer's disease (AD).[42] The study identified proteins such as ubiquitin and phosphorylated C-terminal fragment of osteopontin as potential biomarkers. Here, SPP1 is linked to early-onset autosomal dominant Alzheimer disease.