NTN1 and astrocytoma (excluding glioblastoma): Within astrocytomas 77.8%, within anaplastic astrocytomas 62.5% and within GBMs 77.1% of the tumors were NTN1 positive whereas within oligodendrogliomas and oligoastrocytomas only 26.7% and 36.8%, respectively, were NTN1 positive.