RNA samples (RNA concentration: 100 ng\/mL) were extracted from the kidney tissues of both homozygous knockout and wild-type mice and subjected to gene array analyses (Agilent Technologies, Santa Clara, CA) (GEO array GES57590). RNA samples were extracted from the blood of healthy subjects and patients with OPLL, and then subjected to microRNA array analyses (Agilent Technologies, Santa Clara, CA) (GEO array GES57592). Total RNA was isolated from frozen whole tissue samples with TRIzol (Invitrogen, Carlsbad, CA, USA), and from blood samples with Blood RNA Tubes (PAXgene; PreAnalytiX, Hombrechtikon, Switzerland). RNA samples with RIN values \u2265\u20099.0 as evaluated using a 2100 Bioanalyzer (Agilent, Waldbronn, Germany) were selectively used for these analyses. Pathway analysis was performed based on results of genomic and miRNA arrays (Agilent Technologies, Santa Clara, CA, USA) of samples from patients with OPLL.