To evaluate the effect of ERK5 inhibition on cancer stem-like cell response to 5-fluorouracil (5-FU)-based chemotherapy, fully formed HCT116-derived tumorspheres were treated with FOLFOX (5-FU plus oxaliplatin) or FOLFIRI (5-FU plus irinotecan), alone or in combination with XMD8-92 (Fig. 4a). The gene discussed is MAPK7; the disease is cancer.