A method and device treats cancer where blood from a cancer patient passes through an array of passageways within an interior of a chamber. The passageways include wells having porous membrane wall portions that enable a molecular-sized activating agent in a carrier fluid that enhances an immune response to pass through these porous wall portions. Pore size is such to allow the molecular-sized activating agent in the interior of the chamber to enter the wells yet prevents immune cells and cancer cells in the wells to pass through the porous wall portions into the interior of the chamber. Blood is retained in the wells so that it remains in contact with the immune cells and cancer cells for a predetermined period sufficient to enhance an immune response. Then the cells with an enhanced immune response are return to the patient.