Gene Therapy to cure Cancer

Context

Scientists in the United Kingdom testing a new form of cancer therapy, reported success in a teenage girl, Alyssia, with a form of cancer called T-cell acute lymphoblastic leukaemia.

Alyssia was the first to receive experimental gene therapy that relied on a new technique called ‘base editing.’

What is T-cell acute lymphoblastic leukaemia?

In this form of blood cancer, the T-cells, which are a class of white blood cells, equipped to hunt and neutralise threats to the body, turn against the body and end up destroying healthy cells that normally help with immunity.
The disease is rapid and progressive and is usually treated by chemotherapy and radiation therapy.

What is ‘base editing?’

A person’s genetic code is several permutations of four bases:
- Adenine (A)
- Guanin (G)
- cytosine (C)
- thymine (T)
Sequences of these bases, akin to letters in the alphabet, spell out genes that are instructions to produce the wide array of proteins necessary for the body’s functions.
In the last two decades, the world of biomedical engineering has been enthused by a technique that allows genes to be altered and errors ‘fixed.’
- The most popular among these approaches has been the CRISPR-cas9 system.
  - Inspired by how certain bacteria defend themselves against viruses, by snipping out and storing pieces of their genes, the CRISPR-Cas 9 system, consists of an enzyme that acts like molecular scissors.
  - It can be made to cut a piece of DNA at a precise location and a guide RNA can be used to insert a changed genetic code at the sites of the incision.
  - While there are a few ways to effect such changes, the CRISPR-cas9 system is believed to be the fast, most versatile system to effect such gene editing.
- While still a nascent technology, base editing is reportedly more effective at treating blood disorders which are caused by so-called single point mutations, or when a change in a single base pair can cause terminal disease.