POU3F2 and neoplasm: After 7 days of doxycycline treatment, BRN2 knockdown (shBRN2) tumors recommenced growth; however tumors ablated of MITF (shMITF) continued to decrease in volume resulting in a significantly reduced tumor volume until day 14 after initiation of doxycycline treatment (Fig. 3d, Day 14, P < 0.0001; Mann-Whitney test; raw individual tumor data shown in Supplementary Figure S6a).