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. The cytochemical technique was applied on touch preparations performed in the operating room form biopsy specimens.

Results: Enzyme activity was apparent as cytoplasmic granules sometimes overlying the nucleus of tumor cells.

Conclusions: Activity of dihydrofolate reductase in the children with medulloblastomas and high-grade gliomas was higher than that reported in leukemic blast cells. In the other brain tumors, low grade gliomas, and ependymomas, the enzyme activity was weaker.