Could Diet and Gut Bacteria Be Fueling Early CRC?

This transcript has been edited for clarity. 

I’d like to reflect a little on the ever-rising incidence of early-onset colorectal cancer. I saw two patients in the clinic on Friday, both in their early thirties, presenting with stage IV disease. Both had young families — a disaster.

This is an issue that we must address, I think, epidemiologically. We know that early-onset colorectal cancer is defined as a disease arising in those under the age of 50. There’s been a very sharp increase globally over the past 20-30 years, and currently, around 200,000 such cases are diagnosed every year, but it is said to increase unquestionably.

The epidemiologists, I think, correctly have identified that this sharp, rapid increase does imply that there is a new environmental change that is underpinning or underscoring this rise in early-onset disease. 

There’s a fantastic team that has been put together by Paul Brennan, Mike Stratton, and colleagues, a collaborative group of epidemiologists, geneticists, and bioinformaticians, who are looking at a global study to try to understand the basis of early-onset colorectal cancer. Their approach is to combine conventional epidemiology, genomics, and fantastic computational support to try to unpick the mutational signatures involved.

The dominant hypothesis is that, over the past 20-25 years or so, there has been a change in diet that has allowed an alteration in the gut microbiome such that we now harbor, in some cases, more bacteria capable of manufacturing, synthesizing, and releasing mutagenic chemicals. There’s a subtype of Escherichia coli which manufactures one such mutagen called colibactin.

Again, through some of the painstaking, extraordinary work that Mike Stratton and colleagues have done at the Sanger Institute, they have managed to, using a variety of different techniques — in vitro, observational, and so on — relate exposure to the mutagen colibactin to a particular mutational signature.

They plan to do a large global study — one of the strengths — involving many different countries around the globe, collect material from older colorectal cancer patients and early-onset colorectal cancer patients, and undertake a staggeringly large mutational study to see if the mutational signature associated with colibactin is more highly represented in these early-onset cases. The hypothesis is that, if you’re exposed to this mutagen in childhood, then it increases the tumor mutational burden and therefore the likelihood of developing cancer at an earlier age. 

All of us believe that converting a normal cell into a tumor cell usually requires five or six or seven separate mutational events occurring at random. The earlier these occur, the greater the tumor, the greater the normal single-cellular mutational burden, and the more likely it is to develop cancer sooner rather than later. 

This is a fantastically interesting study, and it’s the way ahead with modern genetic epidemiology, one would say. We wish them well. This will be a 3- to 5-year truly international effort, bringing together a genuinely internationally outstanding research team. We hope that they are able to shed more light on the epidemiology of this early-onset disease, because only by understanding can we deflect and deal with it. 

Knowledge is power, as I’ve said many times before. If we understand the underlying epidemiology, that will allow us to intervene, one would hope, and avoid the chaotic disaster of my clinic on Friday, with these two young patients with an extremely limited lifespan and large families who will be left bereft in having lost a parent.

More power to the team. We wish them well with the study, but again, this is a pointer to the future, one would hope, of modern genetic computational epidemiology. 

I’d be really interested in any ideas or comments that you might have. Are you in the field? Are you seeing more young patients? Do you have any ideas or hypotheses of your own around the microbiome and what bugs might be involved and so on?

Dr. Kerr, Professor, Nuffield Department of Clinical Laboratory Science, University of Oxford, England; Professor of Cancer Medicine, Oxford Cancer Centre, Oxford, United Kingdom, has disclosed relevant financial relationships with Celleron Therapeutics, Oxford Cancer Biomarkers, Afrox, GlaxoSmithKline, Bayer, Genomic Health, Merck Serono, and Roche. 

A version of this article appeared on Medscape.com.

This transcript has been edited for clarity. 

I’d like to reflect a little on the ever-rising incidence of early-onset colorectal cancer. I saw two patients in the clinic on Friday, both in their early thirties, presenting with stage IV disease. Both had young families — a disaster.

This is an issue that we must address, I think, epidemiologically. We know that early-onset colorectal cancer is defined as a disease arising in those under the age of 50. There’s been a very sharp increase globally over the past 20-30 years, and currently, around 200,000 such cases are diagnosed every year, but it is said to increase unquestionably.

The epidemiologists, I think, correctly have identified that this sharp, rapid increase does imply that there is a new environmental change that is underpinning or underscoring this rise in early-onset disease. 

There’s a fantastic team that has been put together by Paul Brennan, Mike Stratton, and colleagues, a collaborative group of epidemiologists, geneticists, and bioinformaticians, who are looking at a global study to try to understand the basis of early-onset colorectal cancer. Their approach is to combine conventional epidemiology, genomics, and fantastic computational support to try to unpick the mutational signatures involved.

The dominant hypothesis is that, over the past 20-25 years or so, there has been a change in diet that has allowed an alteration in the gut microbiome such that we now harbor, in some cases, more bacteria capable of manufacturing, synthesizing, and releasing mutagenic chemicals. There’s a subtype of Escherichia coli which manufactures one such mutagen called colibactin.

Again, through some of the painstaking, extraordinary work that Mike Stratton and colleagues have done at the Sanger Institute, they have managed to, using a variety of different techniques — in vitro, observational, and so on — relate exposure to the mutagen colibactin to a particular mutational signature.

They plan to do a large global study — one of the strengths — involving many different countries around the globe, collect material from older colorectal cancer patients and early-onset colorectal cancer patients, and undertake a staggeringly large mutational study to see if the mutational signature associated with colibactin is more highly represented in these early-onset cases. The hypothesis is that, if you’re exposed to this mutagen in childhood, then it increases the tumor mutational burden and therefore the likelihood of developing cancer at an earlier age. 

All of us believe that converting a normal cell into a tumor cell usually requires five or six or seven separate mutational events occurring at random. The earlier these occur, the greater the tumor, the greater the normal single-cellular mutational burden, and the more likely it is to develop cancer sooner rather than later. 

This is a fantastically interesting study, and it’s the way ahead with modern genetic epidemiology, one would say. We wish them well. This will be a 3- to 5-year truly international effort, bringing together a genuinely internationally outstanding research team. We hope that they are able to shed more light on the epidemiology of this early-onset disease, because only by understanding can we deflect and deal with it. 

Knowledge is power, as I’ve said many times before. If we understand the underlying epidemiology, that will allow us to intervene, one would hope, and avoid the chaotic disaster of my clinic on Friday, with these two young patients with an extremely limited lifespan and large families who will be left bereft in having lost a parent.

More power to the team. We wish them well with the study, but again, this is a pointer to the future, one would hope, of modern genetic computational epidemiology. 

I’d be really interested in any ideas or comments that you might have. Are you in the field? Are you seeing more young patients? Do you have any ideas or hypotheses of your own around the microbiome and what bugs might be involved and so on?

Dr. Kerr, Professor, Nuffield Department of Clinical Laboratory Science, University of Oxford, England; Professor of Cancer Medicine, Oxford Cancer Centre, Oxford, United Kingdom, has disclosed relevant financial relationships with Celleron Therapeutics, Oxford Cancer Biomarkers, Afrox, GlaxoSmithKline, Bayer, Genomic Health, Merck Serono, and Roche. 

A version of this article appeared on Medscape.com.

This transcript has been edited for clarity. 

I’d like to reflect a little on the ever-rising incidence of early-onset colorectal cancer. I saw two patients in the clinic on Friday, both in their early thirties, presenting with stage IV disease. Both had young families — a disaster.

This is an issue that we must address, I think, epidemiologically. We know that early-onset colorectal cancer is defined as a disease arising in those under the age of 50. There’s been a very sharp increase globally over the past 20-30 years, and currently, around 200,000 such cases are diagnosed every year, but it is said to increase unquestionably.

The epidemiologists, I think, correctly have identified that this sharp, rapid increase does imply that there is a new environmental change that is underpinning or underscoring this rise in early-onset disease. 

There’s a fantastic team that has been put together by Paul Brennan, Mike Stratton, and colleagues, a collaborative group of epidemiologists, geneticists, and bioinformaticians, who are looking at a global study to try to understand the basis of early-onset colorectal cancer. Their approach is to combine conventional epidemiology, genomics, and fantastic computational support to try to unpick the mutational signatures involved.

The dominant hypothesis is that, over the past 20-25 years or so, there has been a change in diet that has allowed an alteration in the gut microbiome such that we now harbor, in some cases, more bacteria capable of manufacturing, synthesizing, and releasing mutagenic chemicals. There’s a subtype of Escherichia coli which manufactures one such mutagen called colibactin.

Again, through some of the painstaking, extraordinary work that Mike Stratton and colleagues have done at the Sanger Institute, they have managed to, using a variety of different techniques — in vitro, observational, and so on — relate exposure to the mutagen colibactin to a particular mutational signature.

They plan to do a large global study — one of the strengths — involving many different countries around the globe, collect material from older colorectal cancer patients and early-onset colorectal cancer patients, and undertake a staggeringly large mutational study to see if the mutational signature associated with colibactin is more highly represented in these early-onset cases. The hypothesis is that, if you’re exposed to this mutagen in childhood, then it increases the tumor mutational burden and therefore the likelihood of developing cancer at an earlier age. 

All of us believe that converting a normal cell into a tumor cell usually requires five or six or seven separate mutational events occurring at random. The earlier these occur, the greater the tumor, the greater the normal single-cellular mutational burden, and the more likely it is to develop cancer sooner rather than later. 

This is a fantastically interesting study, and it’s the way ahead with modern genetic epidemiology, one would say. We wish them well. This will be a 3- to 5-year truly international effort, bringing together a genuinely internationally outstanding research team. We hope that they are able to shed more light on the epidemiology of this early-onset disease, because only by understanding can we deflect and deal with it. 

Knowledge is power, as I’ve said many times before. If we understand the underlying epidemiology, that will allow us to intervene, one would hope, and avoid the chaotic disaster of my clinic on Friday, with these two young patients with an extremely limited lifespan and large families who will be left bereft in having lost a parent.

More power to the team. We wish them well with the study, but again, this is a pointer to the future, one would hope, of modern genetic computational epidemiology. 

I’d be really interested in any ideas or comments that you might have. Are you in the field? Are you seeing more young patients? Do you have any ideas or hypotheses of your own around the microbiome and what bugs might be involved and so on?

Dr. Kerr, Professor, Nuffield Department of Clinical Laboratory Science, University of Oxford, England; Professor of Cancer Medicine, Oxford Cancer Centre, Oxford, United Kingdom, has disclosed relevant financial relationships with Celleron Therapeutics, Oxford Cancer Biomarkers, Afrox, GlaxoSmithKline, Bayer, Genomic Health, Merck Serono, and Roche. 

A version of this article appeared on Medscape.com.