Selected marker correlations across patient groups. The four panels show relationships between markers: Panel A between sAPPα and sAPPβ, Panel B between Aβ1-42 and sAPPβ, Panel C between Aβ1-42 and sAPPα, and Panel D between p-tau and t-tau. Symbols for all four panels are defined in Panel A. The diagonal lines show linear regressions with 95% confidence intervals; each panel lists the P value and r2 for the regression. Abbreviations are those given in Figure 1.