APOE and Alzheimer disease: APOE4 emerged as the strongest predictor of myofibroblast abundance (odds ratio = 5.51 ± 0.28, p < 0.0001), and even in the absence of AD, carriers exhibited significantly higher myofibroblast proportions than APOE3/3 individuals (19.80 ± 2.13% increase, p < 0.0001; Figure 1K, Extended Data 2E), suggesting that APOE4 itself promotes myofibroblast accumulation.