Explanation:

Chinese scientists will perform the world’s first genetic editing trial on humans , in an attempt to find a cure for lung cancer.
? A group of oncologist at the West China Hospital of Sichuan University, Chengdu, will inject patients with cells that have been modified using the CRISPR-Cas9 gene-editing technique.
? Doctors will extract T cells, a type of immune cell, from the patient’s blood and then knock out the gene that encodes the PD-1 protein, which normally limits the cell’s capacity to launch an immune response. The edited cells will be multiplied in the lab before being reintroduced to the patients. This process will hopefully kick-start the T cells to launch an attack on the tumour cells. It is like building a cancer-fighting army outside the patient body
About CRISPRs (Clustered Regularly Interspersed Short Palindromic Repeats)
? CRISPRs are elements of an ancient system that protects bacteria and other single-celled organisms from viruses, acquiring immunity to them by incorporating genetic elements from the virus invaders.
? CRISPRs evolved over millions of years to trim pieces of genetic information from one genome and insert it into another. And this bacterial antiviral defense serves as an astonishingly cheap, simple, elegant way to quickly edit the DNA of any organism in the lab.
? Discovery of CRISPRs has changed gene therapy. CRISPRs work by using an enzyme — Cas9 — that homes in on a specific location in a strand of DNA. The process then edits the DNA to either remove unwanted sequences or insert payload sequences. CRISPRs use an RNA molecule as a guide to the DNA target