Characterization of the different steps of the <i>in vitro</i> model of HMEC transformation.

<p>(A) Schematic representation of the successive steps of the transformation. (B,C,D,E) Evaluation of the ability of HMEC-derived cell lines to grow as non-adherent mammospheres. Scale bars = 100 µm. FACS analysis of CD24 and CD44 markers in HMEC-derived cell lines (F,G,H,I). B and F: Primary Human Mammary Epithelial Cell, (HMECs); C and G: hTERT- immortalized HMECs (HME); D and H: HME expressing SV40 small t and large T antigens (HMLE); E and I: H-Ras^V12-infected HMLE cells (HMLER).