Cancer-related deaths are still the most fearsome threaten to human health. It is necessary to develop an innovative and active strategy for the prophylactic immunization against tumorigenesis. Multiple lines of evidence have demonstrated that cancer stem cells (CSCs) are the initiating cells of tumor formation, as well as the source of local recurrence and distant metastases. Mesenchymal stem cells (MSCs), the adult pluripotent progenitors of multiple mesenchymal lineages, have an unusual tropism to preclinical tumor lesions. Both MSCs and CSCs or populations of tumor-initiating cells may also have similar reactogenicity or immunogenicity. Based on the information given above, a hypothesis is generated that MSCs may possess a potential of cellular vaccine for bio-prevention against tumorigenesis via eliciting cross-immunity and inducing active antibodies.