On the cover: Bone marrow stromal cell monolayers were treated with a prototypic aryl hydrocarbon receptor agonist, 7,12-dimethylbenz[a] anthracene (DMBA). Monolayers were washed, and cloned bone marrow pro/preB cells were centrifuged onto the monolayer. Fluorescent DMBA metabolites from stromal cells (pink) can be seen accumulating in adjacent B cells (blue), likely through membrane transfer. Teague, J. E., H-Y. Ryu,M. Kirber, D.H. Sherr, and J. J. Schlezinger. 2010. Proximal events in 7,12-dimethylbenz[a]anthracene-induced, stromal cell-dependent bone marrow B cell apoptosis: stromal cell–B cell communication and apoptosis signaling. J. Immunol. 185: 3369–3378.