American scientists have used CRISPR technology for the first time to insert genes that allow immune cells to find and destroy cancer cells more effectively. The results of the study by scientists from the University of California, Los Angeles, and PACT Pharma were published in the journal Nature. The study involved 16 patients with various types of solid (solid) tumors, including colon, breast and lung cancers. Blood immune cells were isolated from the patients. Human immune cells have receptor molecules on their surface that can specifically recognize cancer cells and distinguish them from normal cells. The receptors are different for each patient. Scientists decoded the sequence of genes encoding these receptors, and then the resulting sequences were inserted into the genome of the patients' immune cells using the CRISPR system. After chemotherapy, patients received up to three doses of cells with the edited genome. Two patients experienced side effects that could have been caused by the cells with the edited genome: one had fever and chills and the other had confusion, but both recovered quickly. Treatment slowed cancer progression in five patients. A biopsy confirmed that the immune cells predominantly attacked the tumor rather than healthy tissue.