A miR-520b sequence for inhibiting cancer growth and spread includes miR-520b sequence for inhibiting cancer growth and spread wherein the miR-520b sequence is 5′-AAAGUGCUUCCUUUUAGAGGGtt-3′ of SEQ ID NO:2. A medicine for inhibiting cancer growth and spread includes a medicinal preparation including miR-520b substrate and medical agent wherein the miR-520b substrate is miR-520b sequence and has concentration of 50 μM, and the miR-520b sequence is 5′-AAAGUGCUUCCUUUUAGAGGGtt-3′ of SEQ ID NO:2.