The New Science of Genetic Medicine
By: Nigel Whittle
Head of Medical & Healthcare
9th January 2019
With surprisingly little fanfare, in October 2018 NHS England became the first health service in the world to routinely offer genetic medicine in the fight to treat cancer.
From that date, hospitals across England have been linked to specialist centres that can read, analyse and interpret DNA isolated from patients with cancer. Through this service, cancer patients can be screened for the existence of key mutations within their tumours that can indicate the best drugs for treatment or to point towards clinical trials of experimental therapies that may be beneficial.
The move marks a big step toward “precision medicine”, which offers more effective therapies that are tailored to individual patients.
What is the science underpinning this move?
Firstly, a quick crash course in cancer biology:
- Cells are the building blocks of every living organism. The instructions (or genes) that tell a cell how to develop and what to do are encoded in long linear molecules of DNA found in the nucleus of the cell.
- These DNA molecules can be damaged over time or through exposure to chemicals or environmental changes. Cells become cancerous when specific changes in the DNA, called ‘driver mutations’, tell cells to grow faster and behave abnormally.
- Many cancers form solid tumours, which are masses of tissue, while cancers of the blood, such as leukaemia, generally do not form solid tumours.
- As these cancer cells multiply to form a tumour, selective pressure increases the number and type of harmful mutations found within the DNA.
- The cells may acquire additional properties through mutation, such as malignancy which means that they can spread into, or invade nearby tissues. In addition, as these tumours grow, some cancer cells break off and travel to distant parts of the body and form new tumours far from the original site.
Accordingly, although every cell of a particular cancer is related to the same original “parent” cell, the mixture of cells within a tumour becomes increasingly complex. The idea that different kinds of cells make up one cancer is called “tumour heterogeneity”, and in practice means that every cancer is unique. So two people with, say, lung cancer who are the same age, height, weight, and ethnicity, and who have similar medical histories, will almost certainly have two very different cancers.
By the time a cancer tumour is 1cm in diameter, the millions of cells within it are very different from each other, and each cancer has its own genetic identity created by the DNA in its cells.
This, of course, makes the treatment of cancer incredibly difficult and explains why scientific breakthroughs in the understanding of cancer biology do not always lead to significant improvements in overall survival rates.
How will cancer treatment change?
Precision medicine is an approach to patient care that allows doctors to select the best treatments for patients based on a genetic understanding of their disease. The idea of precision medicine is not new, but recent advances in science and technology have allowed the ideas to be brought more fully into clinical use.
Normally, when a patient is diagnosed with cancer, he or she receives a standard treatment based on previous experience of treating that disease. But typically, different people respond to treatments differently, and until recently doctors didn’t know why. But now the understanding that the genetic changes within one person’s cancer may not occur in others with the same type of cancer has led to a better understanding of which treatments will be most effective.
At the simplest level, this understanding allows targeted therapy against cancer, in which drugs (quite often complex biological molecules) are used to target very specific genetic changes in cancer cells. For example, around 15–20% of malignant breast cancers contain cells with a higher than normal level of a protein called HER2 on their surface, which stimulates them to grow. When combined with a suitable test, it means that not only can the drug be given to those patients most likely to benefit, but also the drug, with its associated side effects, need not be given to patients who will not benefit from its use.
So genetic medicine has already transformed the treatment of some cancer patients. The advent of widespread genetic medicine within the NHS is likely to lead to significant benefits for cancer patients, including:
- The identification of patients who are most likely to benefit from particular cancer therapy.
- The avoidance of unnecessary treatments that are less likely to work for specific groups of patients.
- The development of novel therapies targeted at specific tumour cells or cellular pathways.
Not only will precision medicine allow the development of precise and effective treatment strategies for cancer patients whilst improving the overall quality of life, but it will also finally destroy the myth of ‘one size fits all’ cancer therapy.
For an informative chat on how Plextek can assist with your Healthcare technology project, please contact Nigel at hello@plextek.com
With surprisingly little fanfare, in October 2018 NHS England became the first health service in the world to routinely offer genetic medicine in the fight to treat cancer.
From that date, hospitals across England have been linked to specialist centres that can read, analyse and interpret DNA isolated from patients with cancer. Through this service, cancer patients can be screened for the existence of key mutations within their tumours that can indicate the best drugs for treatment or to point towards clinical trials of experimental therapies that may be beneficial.
The move marks a big step toward “precision medicine”, which offers more effective therapies that are tailored to individual patients.
What is the science underpinning this move?
Firstly, a quick crash course in cancer biology:
- Cells are the building blocks of every living organism. The instructions (or genes) that tell a cell how to develop and what to do are encoded in long linear molecules of DNA found in the nucleus of the cell.
- These DNA molecules can be damaged over time or through exposure to chemicals or environmental changes. Cells become cancerous when specific changes in the DNA, called ‘driver mutations’, tell cells to grow faster and behave abnormally.
- Many cancers form solid tumours, which are masses of tissue, while cancers of the blood, such as leukaemia, generally do not form solid tumours.
- As these cancer cells multiply to form a tumour, selective pressure increases the number and type of harmful mutations found within the DNA.
- The cells may acquire additional properties through mutation, such as malignancy which means that they can spread into, or invade nearby tissues. In addition, as these tumours grow, some cancer cells break off and travel to distant parts of the body and form new tumours far from the original site.
Accordingly, although every cell of a particular cancer is related to the same original “parent” cell, the mixture of cells within a tumour becomes increasingly complex. The idea that different kinds of cells make up one cancer is called “tumour heterogeneity”, and in practice means that every cancer is unique. So two people with, say, lung cancer who are the same age, height, weight, and ethnicity, and who have similar medical histories, will almost certainly have two very different cancers.
By the time a cancer tumour is 1cm in diameter, the millions of cells within it are very different from each other, and each cancer has its own genetic identity created by the DNA in its cells.
This, of course, makes the treatment of cancer incredibly difficult and explains why scientific breakthroughs in the understanding of cancer biology do not always lead to significant improvements in overall survival rates.
How will cancer treatment change?
Precision medicine is an approach to patient care that allows doctors to select the best treatments for patients based on a genetic understanding of their disease. The idea of precision medicine is not new, but recent advances in science and technology have allowed the ideas to be brought more fully into clinical use.
Normally, when a patient is diagnosed with cancer, he or she receives a standard treatment based on previous experience of treating that disease. But typically, different people respond to treatments differently, and until recently doctors didn’t know why. But now the understanding that the genetic changes within one person’s cancer may not occur in others with the same type of cancer has led to a better understanding of which treatments will be most effective.
At the simplest level, this understanding allows targeted therapy against cancer, in which drugs (quite often complex biological molecules) are used to target very specific genetic changes in cancer cells. For example, around 15–20% of malignant breast cancers contain cells with a higher than normal level of a protein called HER2 on their surface, which stimulates them to grow. When combined with a suitable test, it means that not only can the drug be given to those patients most likely to benefit, but also the drug, with its associated side effects, need not be given to patients who will not benefit from its use.
So genetic medicine has already transformed the treatment of some cancer patients. The advent of widespread genetic medicine within the NHS is likely to lead to significant benefits for cancer patients, including:
- The identification of patients who are most likely to benefit from particular cancer therapy.
- The avoidance of unnecessary treatments that are less likely to work for specific groups of patients.
- The development of novel therapies targeted at specific tumour cells or cellular pathways.
Not only will precision medicine allow the development of precise and effective treatment strategies for cancer patients whilst improving the overall quality of life, but it will also finally destroy the myth of ‘one size fits all’ cancer therapy.
For an informative chat on how Plextek can assist with your Healthcare technology project, please contact Nigel at hello@plextek.com
