Releasing Breaks on the Immune system to eliminate cancerous tumor cells

Well deserved 2018 Nobel prize in Medicines have been given to two giant immunologists James Allison of MD Anderson Cancer Center and Tasuku Honjo of Kyoto University for tweaking our own immune system (immunotherapies) to better fight cancer than our present methods of surgery, Radiation and chemotherapy.

Allison group focused on CTLA-4, a protein on the surface of T-cells that inhibits our immune system to fight against cancer. Earlier in 1996 this group showed that antibodies against CTLA-4 not only got rid of cancer but prevented new tumors from forming in mice. In 2003 Allison and his team showed up that anti-CTL4-antibody could regress metastatic melanoma but skepticism prevailed amongst scientists that immunotherapies work only in mice. But in 2011 FDA(Food and Drug Administration) approved an antiCTLA-4 (ipilimumab) as treatment for late stage melanoma.

It was not acceptable for the Tasuku Honjo group to merely mimic the work of other labs. Hongo and his colleagues in 1991 worked on another T-cell protein called PD-1 or programmed death-1 and also studied how it acted as break on T-cells. Between 2000-2002 these scientists described PD-L1 and PD-L2(Programmed death ligand-1 and 2, protein found on normal as well as cancerous cells and also demonstrated that blocking PD-1 eradicates tumors not only in mice but also in humans. The FDA approved first PD-1 checkpoint inhibitor (pembrolizumab) to treat melanoma in 2014. Since then FDA has approved at least four other PD-1 inhibitor for the treatment of nine type of cancer.

A combination therapy targeting both CTLA-4 and PD-1 is now in development to eliminate tumor cells even more efficiently.
https://www.the-scientist.com/news-opinion/james-allison-and-tasuku-honjo-win-nobel-prize-64879