TREM2 and Alzheimer disease: Notably, apolipoprotein E (Apoe), TYRO protein tyrosine kinase binding protein (Tyrobp), and triggering receptor expressed in myeloid cells 2 (Trem2), which are known high-risk genes for the development of late-onset AD and are highly expressed in microglia28, showed strong upregulation in both late phenotype changes and AD maturation.