These included several previously reported AD biomarkers [24, 25], such as microtubule-associated protein tau (MAPT) [26], neurofilament light chain protein (NEFL) [27], growth associated protein 43 (GAP43) [28], fatty acid binding protein 3 (FABP3) [29], osteopontin (SPP1) [30, 31], and chitinase 3 like 1 (CHI3L1; also known as YKL-40) [32]. Here, SPP1 is linked to Alzheimer disease.