A human ex vivo study investigating the response to TOP2 poisons in short-term cultures derived from malignant gliomas demonstrated that both etoposide and doxorubicin are toxic to these tumor cells (18), while another study in rat models designed to study combination TOP1 + TOP2 therapies showed doxorubicin toxicity toward GBM cell lines (19). Here, TOP2A is linked to glioblastoma.