Valproic acid induces differentiation of a supratentorial primitive neuroectodermal tumor

In preclinical models the antiepileptic drug valproic acid induces differentiation of neoplastic cells, representing an evolving anticancer approach that takes into account that malignant cells resemble immature progenitor cells capable of terminal differentiation. The authors report on a child suffering from a relapsing supratentorial primitive neuroectodermal tumor that received valproic acid for epilepsy treatment over 7 months before the relapse. In contrast to the initial tumor, the relapsing tumor showed glial differentiation and low proliferation index. This is the first report of a relapsed supratentorial primitive neuroectodermal tumor that shows histologically confirmed signs of tumor cell differentiation induction.