Trying everything they could in mice to tweak the immune system, Krummel and Allison soon found that a protein receptor called CTLA-4 seemed to be holding T cells back, like a brake in a vehicle.
He said the idea of releasing the brakes on immune system cells has led to drugs for the skin cancer melanoma and for cancers of the lung, head and neck, bladder, kidney and liver.
The scientists' work in the 1990s has since swiftly led to new and dramatically improved therapies for cancers such as melanoma and lung cancer, which had previously been extremely hard to treat.
One of Carter's treatments was a drug that blocked the immune-cell "brake" studied by Honjo.
"It represents a completely new principle because, unlike the previous strategies, it is not based on targeting the cancer cells but rather the brakes, the checkpoints of the host immune system", he said.
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". The victor of the Nobel Peace Prize will be named Friday.
Antibodies against PD-1 have been approved by the US Food and Drug Administration as an investigational new drug and developed for the treatment of cancer. From 1977-1984 he was a faculty member at University of Texas System Cancer Center, Smithville, Texas; from 1985-2004 at University of California, Berkeley and from 2004-2012 at Memorial Sloan-Kettering Cancer Center, New York.
Science magazine named cancer immunotherapy its breakthrough of 2013 because that year, "clinical trials ... cemented its potential in patients and swayed even the skeptics".
Raj Kapoors wife Krishna Raj passes away
She further added, "In our long conversations, Raj-ji often spoke about Krishna-ji and all she had brought into his life". May your soul RIP and deepest condolences to Rishi Kapoor and family. "My deepest condolences to the family", she wrote.
"When we showed (Professor Ralph) Reisfeld a paper we wrote, he actually said, 'I don't want my name on it".
"I'm honored and humbled to receive this prestigious recognition", Allison said in a statement.
"I would like to keep on doing my research.so that this immune treatment could save more cancer patients", he said.
James P. Allison of MD Anderson Cancer Center at The University of Texas in this picture obtained from MD Anderson Cancer Center (R) and Kyoto University Professor Tasuku Honjo in Kyoto, in this photo taken by Kyodo. Carter announced in 2016 that he no longer needed treatment.
For the first time since 1949, the Swedish Academy has postponed the announcement of the 2018 Nobel Literature Prize until next year, amid a #MeToo scandal and bitter internal dispute that has prevented it from functioning properly.
The Nobel Prize for physics is set to be announced on Tuesday.
At the time, most doctors and scientists believed that the immune system could not be exploited to fight cancer, because cancer cells look too much like the body's own cells, and any attack against cancer cells would risk killing normal cells and creating serious side effects.