Altered localization of p27 in differentiating myeloid cells. CD34⁺ cells were differentiated for 0 (A, E), 6 (B), 9 (C, F), or 15 (D, G) days and aliquots taken at various intervals for p27 immunostaining by using peroxidase detection. Cytospins shown have been indirectly stained either with isotype control (E-F) or anti-p27 antibody (Neomarkers Ab-1; A-D). Altered patterns of p27 immunoreactivity are evident.