CHI3L1 and Alzheimer disease: Our analysis revealed 515 unique proteins, many of which are proteins detected in CSF that are differentially expressed in AD (Figure 3G).53 Notably, many of these biomarkers, including NEFL, CHI3L1, and MSN, showed higher expression levels in the TC secretome compared to MC, underscoring the value of comparing both culture types for investigating key proteins of interest (Figure 3H).