The data about its ability to break through the brain-blood barrier are scarce and contradictory,[9,10] but in any case the levels reached in SCF are slightly lower than the concentration in blood, even in patients treated with radiotherapy with known disruptive effect of the brain-blood barrier.[11] Thus, intrathecal therapy seems attractive specially in cases like our patient's, in which there was no clear evidence of disease at any other level, or at least a low tumor burden. The gene discussed is KITLG; the disease is neoplasm.