The 2018 Nobel Prize in Physiology or Medicine has been awarded to James P. Allison and Tasaku Honjo by the Nobel Committee for advances in discovering how the body's immune system can fight off the scourge of cancer.
The prize recognizes Allison's basic science discoveries on the biology of T cells, the adaptive immune system's soldiers, and his invention of immune checkpoint blockade to treat cancer.
The Nobel committee said the pair's research - which harnesses the body's immune system to attack cancer cells - amounted to a "landmark in our fight against cancer".
In 1995, he was one of two scientists to identify the ligand CTLA-4 as an inhibitory receptor on T-cells, which are a type of white blood cell that play a vital role in the body's natural immunity to disease.
Separately, Prof Honjo discovered a new protein on immune cells, finding that that too acts as a brake.
"I'm honored and humbled to receive this prestigious recognition", Allison said in a statement.
Perlmann said he had not yet managed to contact Allison.
Many of Allison's patients are alive and cancer free because of his approach. "They are living proof of the power of basic science, of following our urge to learn and to understand how things work".
"I want to continue my research, so that this immune therapy will save more cancer patients than ever", he told reporters at the University of Kyoto where he is based. "Until the seminal discoveries by the two laureates, progress into clinical development was modest", the Nobel jury said.
Research by Allison's team has meanwhile led to the development of a monoclonal antibody drug, which was approved by the US Food and Drug Administration (FDA) in 2011 for the treatment of melanoma.
His drug, known commercially as Yervoy, became the first to extend the survival of patients with late-stage melanoma.
USA drugmakers Merck & Co and Bristol-Myers Squibb now lead the field after winning drug approvals in 2014, but Roche, AstraZeneca, Pfizer and Sanofi are also fielding rivals.
Allison, who is the chair of Immunology and executive director of the Immunotherapy Platform, is the first MD Anderson scientist to receive the world's most coveted award for discoveries in the fields of life sciences and medicine. The victor of the Nobel Peace Prize will be named Friday and the economics laureate will be announced next Monday.