It relies on immune system cells known as tumor-infiltrating lymphocytes, or TILs. The ones used on Perkins were picked because they could home in on four mutant proteins that were present in all of her cancer cells. An exhaustive search of her blood and a sample of her tumor turned up only 11 of these super-capable immune cells, so the scientists spent four months growing billions of copies in the lab.

Source: Los Angeles Times June 04, 2018 15:00 UTC