APOE and Alzheimer disease: A correlation matrix was generated to visualize the correlation coefficients between the plasma biomarkers, the clinical AD biomarkers (CSF Aβ42, CSF pTau181, MMSE, Atrophy on MRI, Aβ-PET (CL)) (Fig. 2a and b), and the demographic variables/AD risk factors (age, sex, number of APOE-ε4 alleles) (Fig. 2b).