CD44posCD24neg cells possess an invasive, mesenchymal phenotype. (a) Total RNA was isolated from CD44posCD24neg and CD44posCD24pos cells sorted from parental Ca1a cells and transcript abundance was evaluated via realtime RT-PCR. CD44posCD24neg (red bars) and CD44posCD24pos (blue bars) differences are presented using the delta delta Ct method. Graphs represent means and associated standard errors of three independent experiments. * indicates P < 0.05. (b, c) Immunofluorescent staining of Slug (green) (b), vimentin (red) (c), and DAPI (blue) in cytospin preparations derived from parental Ca1a cells sorted into CD44posCD24neg and CD44posCD24pos populations. (d) Invasion through Matrigel by sorted parental Ca1a CD44posCD24neg (red bar) and CD44posCD24pos (blue bar) cells. Invaded cells were counted 48 hr following seeding. Graphs represent averages and associated standard errors of experiments performed in triplicate. * indicates P < 0.05.