Interestingly, apolipoprotein E ε4 (APOE ε4), which is a genetic risk factor for AD and dementia with Lewy bodies, can cause PP2A inactivation by downregulating the expression of PPP2R5E, a regulatory subunit of the PPP2R5 subfamily (Theendakara et al., 2017; Guerreiro et al., 2018). This evidence concerns the gene APOE and Alzheimer disease.