Since age-related decreases in GGA and Maob mRNA expression levels were observed in the normal liver of C3H/HeN mice, next, we measured GGA, Maob mRNA and Maoa mRNA levels in the tissue of spontaneously developed mouse hepatoma in comparison with those in its surrounding normal liver tissue (Supplementary Materials Figure S3). The gene discussed is MAOA; the disease is hepatocellular carcinoma.