Therapy resistances in cancer are often detected too late or undetectable by current methods (CT scan & common liquid biopsy), cause patient death and huge expenses in the medical, economic, and the Medicare systems. The tumor signal transduction oncoproteins insides tumor cells control tumor survival. Based on the world's first invention “Tumor Signal - Liquid Biopsy” method (to assay tumor signal transduction activity in blood from cancer patients), clinical trials showed our innovative diagnostic product (cancer therapy resistance detection reagent) can early and real-time monitor cancer therapy response. Our method enables an early, real-time, sensitive, and cost-saving way in monitoring the therapy resistance of all cancer types and all therapy methods. Our method also enables real-time guiding the optimal doses of drug/radiation in cancer therapy to reduce side-effects, especially for childhood cancer. Our invention resolves the problems of CT scan and common liquid biopsy in monitoring cancer therapy. It can help patients to get the correct drug in time, to avoid patients spending huge money in taking ineffective drugs and losing the golden period of cancer treatment.