KRT14 and skin papilloma: Incubated Tg(krt14:MEK2S219D-GFP) zebrafish larvae with 50 μM at 2 dpf or 0.01 % DMSO as control, no skin papilloma was observed in U0126 treatment at 6 dpf (Fig. 5d) but several skin papilloma was observed in DMSO treatment at 6 dpf (Fig. 5e).