TGFB1 and Alzheimer disease: Specific ELISA assays should be used in future studies to determine serum levels of total, active, and latent TGF-β1 (Pro- TGF-β1) in AD patients and to establish how the SNP at codon +10 (T/C) can interact with the SNP at codon +25 (G/C) in influencing TGF-β1 secretion.