Effect of TAM-induced HOXB4-ER^T2 activity on myeloid CFU-C. (A) TAM-induced cytosol to nucleus translocation of HOXB4-ER^T2 in Lin⁻ BM cells confirmed by confocal microscopy (red represents HOXB4-ER^T2; and blue, nucleus dye). Slides were imaged with a Nikon TE2000-E inverted microscope equipped with a CISi confocal system with EZCl software and an 40×/1.3 NA Plan Apo objective. (B) TAM treatment for 12, 24, and 48 hours induced an increase in secondary myeloid progenitor colony formation in HOXB4-ER^T2-overexpressing Lin⁻ BM cells ex vivo. (C) Pictures of the secondary myeloid progenitor colony plates from HOXB4-ER^T2-overexpressing cells treated with TAM for 0, 12, 24, and 48 hours.