TREM2 and Alzheimer disease: Conversely, P2RY12 expression levels per DAPI+/TREM2+/P2RY12+ microglial cell were increased in cells co-expressing DKK2 compared with cells that lacked DKK2 expression, although that difference was not statistically significant: control (DKK2+: 2.7 ± 1.0 μm2; DKK2–: 1.7 ± 0.5 μm2), pathologic aging (DKK2+: 2.7 ± 0.5 μm2; DKK2–: 2.0 ± 0.9 μm2), and AD individuals (DKK2+: 3.2 ± 1.6 μm2; DKK2–: 1.6 ± 0.8 μm2; Extended Data Fig. 6-1C; one-way ANOVA, p = 0.1056ab).