STOCKHOLM – Japanese scientist Tasuku Honjo was awarded on Monday this year's Nobel Prize in physiology or medicine, for his discovery of a protein that contributed to the development of an immunotherapeutic drug against cancer. Honjo, a 76-year-old professor at Kyoto University, won the prize with U.S. national James Allison, the Nobel Assembly at the Karolinska Institute said. Honjo opened a pathway for a new cancer treatment by discovering the PD-1 protein, which is responsible for suppressing immune response. "I'm very honored and pleased to receive the Nobel Prize in physiology or medicine," Honjo told a news conference following the announcement. His method of treating cancer -- by controlling the protein's function to suppress immunity -- led to the development of Nivolumab, a drug marketed as Opdivo and used against lung cancer and melanoma.