APOE and Alzheimer disease: The extracellular immunoglobulin-like domain of TREM2 recognizes various pathological molecules in AD, including phospholipids (Wang et al., 2015), lapidated particles (Song et al., 2017), APOE (Atagi et al., 2015; Bailey et al., 2015; Yeh et al., 2016), Aβ (Zhao et al., 2018; Zhong et al., 2018), TDP-43 (Xie et al., 2022), galectin-3 (Boza-Serrano et al., 2019), and C1q (Zhong et al., 2023).