Fig. 7.

BMDCs initiate squamous lesions in the skin. a Overview of DMBA-exposed BMT to naive recipients: a-I Carcinogen-exposed donor BMC preparation: FVB/EGFP male donor mice were given one treatment of DMBA (1 mg in 0.5 ml corn oil) via oral gavage and DMBA-exposed whole toxic BMCs were isolated for BMT. a-II Naive female FVB/N mice were prepared as BMT recipients, and twice-weekly topical TPA (5 nmol for 3 weeks followed by 17 nmol in 200 µl of acetone until 18 weeks) promotion followed 5 weeks after BMT for 18 weeks (1. DMBA (BMT donor) ► 2. BMT ► TPA (BMT recipient)). Controls included corn oil/acetone, DMBA/acetone, and corn oil/TPA. None of the controls developed tumors. b K14-positive BMDCs identified from the squamous cell carcinoma sample from DMBA-exposed BMT recipient. All five of the tumors demonstrated co-expression of GFP and K14. Some heterogeneity was observed; however, most of the tumor epithelium was composed of cells of donor origin. Black scale bar, 50 µm. c Flow cytometric analysis: blood, bone marrow, and two disaggregated squamous tumor samples from DMBA-exposed BMT recipients. Native GFP fluorescence is shown in the Y-axis, and EpCAM, an epithelial cell marker, is shown along the X-axis. Note the GFP⁺/EpCAM⁺ double positive cells in quadrant III, and that there are more double positive cells in the blood than in the bone marrow. Note further, GFP^high/EpCAM^high double positive cells are increased in both tumors (red boxes). The single EpCAM⁺ cells in quadrant IV suggest heterogeneity of the tumor epithelium. *Some images in Fig. 7a were generated with AutoDraw