What is base editing, the groundbreaking tech that cleared a teenager’s cancer?

Source: The post is based on the article “What is base editing, the groundbreaking tech that cleared a teenager’s cancer?” published in Indian Express on 14th December 2022

What is the News?

In the UK, a teenage girl’s incurable blood cancer has been cleared from her body through the first use of a revolutionary type of method called Base Editing.

About the T-cell acute lymphoblastic leukaemia(T-ALL)

The girl was diagnosed with a kind of blood cancer known as T-cell acute lymphoblastic leukaemia(T-ALL). 

T-ALL affects the stem cells in the bone marrow that produce a particular kind of white blood cells (WBC) called T lymphocytes (T cells). These cells provide a person immunity by killing cells carrying infections, activating other immune cells, and regulating the immune response.

Note: While found in both children and adults, T-ALL’s incidence decreases with age.

How is T-ALL typically treated?

Typical treatment for T-ALL is similar to that of any leukaemia– chemotherapy and stem cell/bone marrow transplant. 

Doctors will first administer multiple rounds of chemotherapy. This either kills the cancerous cells or stops them from further dividing. The exact schedule is guided by an individual’s age and general health. If this fails, and the individual is suitable, doctors will conduct a bone marrow transplant. 

Overall treatment for T-ALL is pretty effective– children have a survival rate of over 85% after five years of receiving this treatment. Unfortunately, the teenage girl lay in the unlucky 15% of children where the treatment just did not work.

The doctors then used a technology called base editing, which was invented only six years ago.

What is Base Editing Technique?

Bases are the language of life. The four types of base – adenine (A), cytosine (C), guanine (G) and thymine (T) – are the building blocks of the human genetic code. Just as letters in the alphabet spell out words that carry meaning, the billions of bases in human DNA spell out the instruction manual for every human body. 

Base editing allows scientists to zoom into a precise part of the genetic code and then alter the molecular structure of just one base, converting it into another and changing the genetic instructions. 

The doctors in the UK used this tool to engineer a new type of T-cell that was capable of hunting down and killing teenage girl’s cancerous T-cells.