Module 1 was made up of eight nodes and seven edges consisting of specific Alzheimer's disease-associated mRNAs, such as the matrix metalloproteinase-9 (MMP9), the protein fosB (FOSB), the interferon-induced protein with tetratricopeptide repeats 1 (ITFIT1), transcriptional activator Myb (MYB), the cathepsin D (CTSD), the nuclear receptor subfamily 4 group A member 2 (NR4A2), TATA-binding protein-associated factor 2N (TAF15), and the prostaglandin G/H synthase 2 (PTGS2). The gene discussed is CTSD; the disease is Alzheimer disease.