While GFI1 and GFI1B overexpressing tumours show high LSD1 activity that could be blocked using specific chemical inhibitors [30], our findings show that inhibition of LSD1 increases stemness (Fig. 4D and Supplementary Fig. S5D), raising caution over the use of LSD1 inhibitors in the treatment of specific subtypes of medulloblastoma. The gene discussed is GFI1B; the disease is medulloblastoma.