QSOX1 and medulloblastoma: Positive staining for QSOX1 in the fibrillar matrix and cytoplasm of medulloblastoma cells suggests that this enzyme is involved in the formation of the ECM in these tumors, while the positive staining observed in the perinuclear region of medulloblastoma cells may be related to the fact that QSOX1 is found in the Golgi complex.