In October 2016, a team led by a researcher from Sichuan University in Chengdu performed the first human cancer treatment using the "gene scissors" CRISPR/Cas9 in a clinical trial. The patient suffering from aggressive, metastatic non-small cell lung cancer was treated by removing immune cells (T cells) from the blood and using CRISPR/Cas9 to remove the gene for the production of PD-1 protein. The cells were successfully modified and multiplied and then reinjected into the patient. The PD-1 protein plays a major role in suppressing the body's own defense against the tumor, thereby promoting tumor proliferation. The modified T cells, on the other hand, lack the corresponding gene and should be able to attack and destroy the cancer cells. Results of the study are still pending.