As already known, traditional approaches in healing of many kinds of malignant tumors unfortunatelly still gives bad results. Also, our immune system is not able to respond on malignant tumors in an adequate capacity, because they are growing rapidly and they have pretty developed mechanisms in order to avoid our immune response. Potential answer how to accelerate our immune system and make it more responsive to malignant tumors maybe is hidden in an attempt to make tumoral cells infected by viruses. That way viruses would mark tumoral cells and provoke stronger immune response activating apoptosis of tumoral cells as a final effect.