Kunishio et al. evaluated whether 99mTc-MIBI SPECT characteristics of intracranial meningioma were correlated with the histological malignancy, proliferative potential, and Pgp expression, encoded by the multidrug resistance gene-1 (MDR-1) messenger ribonucleic acid (mRNA). The gene discussed is PGP; the disease is intracranial meningioma.