It was believed that tumors originated from the transformation of their tissue-specific stem cells. However, bone marrow-derived cells (BMDCs), which possess an unexpected degree of plasticity and often reside in other tissues, might also represent a potential source of malignancy. To study whether BMDCs play a role in the source of other tumors, BMDCs from mice were treated with 3-methycholanthrene until malignant transformation was achieved. Here we show that transformed BMDCs could form many tumor types, including epithelial tumors, neural tumors, muscular tumors, tumors of fibroblasts, blood vessel endothelial tumors, and tumors of poor differentiation in vivo. Moreover, a single transformed BMDC has the ability to self-renew, differentiate spontaneously into various types of tumor cells in vitro, express markers associated with multipotency, and form teratoma in vivo. These data suggest that multipotent cancer stem cells seemed to originate from transformed BMDCs. Conclusively, these findings reveal that BMDCs might be a source of many tumor types, even teratoma. In addition, multipotent cancer stem cells might originate from malignant transformed BMDCs.