PGP and medulloblastoma: Medulloblastoma, the most frequent childhood primary malignantbrain tumor, is generally treated with a combination therapy thatincludes etoposide, methotrexate, cisplatin, lomustine, cyclophosphamide,and vincristine.7 Recently, it has beendemonstrated that the high frequency of recurrence and therapy failurein medulloblastoma is associated with a high expression of P-gp.