The invention disclosed herein relates generally to immunotherapy and, more specifically, to therapeutic methods for treating tumors and cancerous tissues by first inducing necrosis or apoptosis (e.g., cryotherapy, chemotherapy, radiation therapy, ultrasound therapy, or a combination thereof applied against at least a portion of the tumor or cancerous tissue), and then delivering one or more se doses of antigen presenting cells (e.g., autologous dendritic cells) intratumourally or proximate to the tumor or cancerous tissue, but only after a selected period of time sufficient for the bioavailablity of liberated cancer-specific antigens (monitored over the selected period of time) resulting from the necrosis or apoptosis to be at or near a maximum value. The present invention provides an alternative strategy to the ex vivo loading of target antigen to antigen presenting cells such as, for example, enriched autologous dendritic cells for purposes of enhancing an immune response.