English: (A) Measurable tumors were detected in three of three SP-injected (at 5 × 105 cells) animals at 10 weeks after implantation, whereas zero of three NSP-injected animals demonstrated tumors at the first appearance of SP tumors. (B) SP cells showed only 30% inhibition by MTT assay (P< 4.2 × 10−4) while NSP cells were inhibited 81% (**P<5.1 × 10−10) by doxorubicin versus vehicle controls (shorter bars indicate more inhibition of cell growth). In contrast, (C) the proliferation of MOVCAR 7 SP and NSP cells also analyzed by MTT assay demonstrated inhibition of both SP (*86%) and NSP (**93%) cells by MIS versus vehicle control (shorter bars indicate more inhibition of cell growth). (Adapted with permission from Szotek, P.P., Pieretti-Vanmarcke, R., Masiakos, P.T., Dinulescu, D.M., Connolly, D., Foster, R., Dombkowski, D., Preffer, F., MacLaughlin, D.T., Donahoe, P.K. (2006). Ovarian cancer side population defines cells with stem cell-like characteristics and Müllerian Inhibiting Substance responsiveness. Proc Natl Acad Sci USA 103, 11154–11159. Figures 3A, 4B, and 5E. Copyright 2006 National Academy of Sciences, U.S.A).