The invention generally relates to the prevention and/or treatment of cancer, and, more specifically, to the treatment of tumors, including solid tumors and their metastases, without radiation or standard chemotherapeutic agents. In one embodiment, the invention involves a method comprising: a) providing a subject with tumor cells, b) removing at least a portion of said tumor cells from said subject to create removed cells, c) treating at least a portion of said removed cells ex vivo, using stimulating agents, including thapsigargin and/or thapsigargin-related compounds, so as to create treated tumor cells; and d) introducing said treated tumor cells (or fragments thereof) in vivo into the same subject to generate anticancer therapeutic effects.