Dihydrofolate reductase activity in primary brain tumors in children.

Purpose: Dihydrofolate reductase is an enzyme involved in cell proliferation and differentiation processes. A cytochemical method was used to detect and quantitate this enzyme at the cellular level in brain tumors in children.

Material And Methods: Twenty-six children, aged 1-12 years, with primary brain tumors were studied, eight with medulloblastoma, 10 with glioma, and eight with ependymoma or other tumors.