Microbiome is once again leading scientists toward a new understanding of how human gut bacteria can impact the efficacy and side-effects of certain cancer therapies
Anatomic pathology researchers already know that a person’s genetics can affect the results of cancer treatments. Now it is becoming clear that a patient’s microbiome—which includes gut bacteria—may also impact the efficacy of particular cancer treatments. A recent study showed that gut bacteria can be used to determine whether a cancer drug will work for a certain individual and also if the patient might suffer side effects from certain cancer treatments.
Working with this knowledge, diagnostic test companies may possibly develop new clinical laboratory tests designed to help physicians better diagnose and treat cancer patients. This, in turn, advances personalized medicine and treatments for chronic diseases tailored to patients’ specific physiologies and conditions. This is a healthcare trend where medical laboratories can expect to play a critical role.
Gut Bacteria as Important as Genetics in Cancer Treatments
A recent article published in the journal Nature: npj Biofilms and Microbiomes, outlined a correlation between gut bacteria and side effects of irinotecan (sold as Camptosar), a drug used to treat metastatic colorectal cancer.
Libusha Kelly, PhD, Assistant Professor in the Departments of Systems and Computational Biology, and Microbiology and Immunology, led researchers from the Albert Einstein College of Medicine located in Bronx, N.Y., in conducting the study.
“We’ve known for some time that people’s genetic makeup can affect how they respond to a medication,” noted Kelly in an Einstein news release. “Now, it’s becoming clear that variations in one’s gut microbiome—the population of bacteria and other microbes that live in the digestive tract—can also influence the effects of treatment.”
Irinotecan is administered intravenously to colorectal cancer patients in an inactive form and is metabolized to an active form by liver enzymes. The drug is later converted back to an inactive form by other liver enzymes and the addition of a Glucuronidase chemical group. The irinotecan then enters the intestine for expulsion by the body.
Taken from the Einstein College of Medicine published study, the graph above illustrates “Two distinct metabolizer phenotypes or ‘metabotypes’ based on % SN-38 formation during a time course incubation of SN-38G with fecal samples from 20 individuals quantified by LC-MS/MS. Participants were sub-grouped into low (n = 16) and high (n = 4) metabolizer phenotypes. All samples were run in triplicate and values are the mean ± sem.” (Graphic copyright: Nature/Albert Einstein College of Medicine.)
However, bacteria residing in the digestive tract of some individuals prevent the medication from metabolizing properly and reactivates the medication, which transforms the irinotecan into a toxic substance that can cause side effects.
To perform the research, Kelly and her team collected fecal samples from 20 healthy individuals and treated those samples with inactive irinotecan. The samples were then examined and categorized by whether or not they were able to metabolize or reactivate the drug.
Identifying Potential for Side Effects in Patients a Powerful Tool for Medical Laboratories
Irinotecan can cause severe diarrhea and dehydration in up to 40% of patients who take the medication. By focusing on the presence of beta-glucuronidase (enzymes that are used to catalyze the breakdown of complex carbohydrates) the researchers found that gut bacteria can also be used to distinguish which patients will encounter side effects from the drug.
“As you can imagine, such patients are already quite ill, so giving them a treatment that causes intestinal problems can be very dangerous,” said Kelly in the news release. “At the same time, irinotecan is an important weapon against this type of cancer.”
Four of the 20 subjects in the study were determined to be high metabolizers. Due to differences in the composition of their microbiomes, the team concluded that the high metabolizers were more likely to experience side effects from irinotecan.
The research also demonstrated that beta-glucuronidase enzymes in the gut may adversely interact with some commonplace drugs, such as ibuprofen and other nonsteroidal anti-inflammatory medications (NSAIDs), morphine, and Tamoxifen, a drug that is prescribed mainly to breast cancer patients.
“In these cases, the issue for patients may not be diarrhea,” states Kelly in the news release. “Instead, if gut bacteria reactivate those drugs, then patients might be exposed to higher-than-intended doses. Our study provides a broad framework for understanding such drug-microbiome interactions.”
Microbiome Takes Center Stage in Pathology Research
As Dark Daily previously reported, from extending life to developing more powerful treatments for chronic diseases, the human microbiome is quickly becoming an important subject of research studies. The findings from such studies will trigger advances in precision medicine. And, the clinical laboratory assays developed from this research will give physicians the knowledge needed to select the most appropriate drug therapies and treatments for individual patients.
Gut Bacteria Can Stop Cancer Drugs from Working
Gut Microbiome May Make Chemo Drug Toxic to Patients
Human Microbiome Signatures of Differential Colorectal Cancer Drug Metabolism
Researchers in Two Separate Studies Discover Gut Microbiome Can Affect Efficacy of Certain Cancer Drugs; Will Findings Lead to a New Clinical Laboratory Test?
Attention Microbiologists and Medical Laboratory Scientists: New Research Suggests an Organism’s Microbiome Might Be a Factor in Longer, More Active Lives
Mayo Clinic and Whole Biome Announce Collaboration to Research the Role of the Human Microbiome in Women’s Diseases Using Unique Medical Laboratory Tests
In the same way that BRCA1 and BRCA2 mutations helped pathologists identify women with increased breast cancer risks in the late 1990s, this new study isolates an additional 72 mutations medical laboratories may soon use to diagnose breast cancer and assess risk factors
For 20 years genetic scientists, anatomic pathologists, and medical laboratories have employed the BRCA1/BRCA2 genes to identify women at higher risk for breast cancer. And, because pathologists receive a high number of breast biopsies to diagnose, physicians and clinical laboratories already have collaborative experience working with genetic mutations supported by ample published evidence outlining their relationship with cancer.
Now, a global research study is adding 72 more mutations to the list of mutations already known to be associated with breast cancer.
In coming years, physicians and anatomic pathologists can expect to use the knowledge of these 72 genetic mutations when diagnosing breast cancer and possibly other types of cancers in which these mutations may be involved.
New Precision Medicine Tools to Improve Breast Cancer Survival
Combining the efforts of more than 550 researchers across 300 institutions and six continents, the OncoArray Consortium analyzed the DNA of nearly 300,000 blood samples. The analysis included samples of both estrogen receptor (ER-positive and ER-negative) cases.
Taken from a study published in the British Journal of Cancer, the graph above illustrates “proportions of familial risk of breast cancer explained by hereditary variants.” It is expected that anatomic pathologists will eventually incorporate these genetic variants into diagnostic test for breast and other cancers. (Graphic copyright: British Journal of Cancer.)
The results of their research were published in two separate studies: one in the scientific journal Nature and the other in Nature Genetics. The studies outlined 72 newly isolated genetic mutations that might help quantify the risk of a woman developing breast cancer in her lifetime.
Among the 72 mutations, seven genes were specifically associated with ER-negative cases. ER-negative breast cancer often fails to respond to hormone therapy. Thus, this discovery could be crucial to developing and administering precision medicine therapies tailored to specific patients’ physiologies and conditions. Treatments that improve patient outcomes and overall survival rates in ER-negative and ER-positive breast cancers.
Genetics Could Help Clinical Laboratories Wage War on All Cancers
According to data published by the Centers for Disease Control and Prevention (CDC), breast cancer is the most common form of cancer among women of all races. It’s the second-leading cause of all cancer deaths among most races and first among Hispanic women.
In the past, it was estimated that 5-10% of breast cancers were inherited through the passing of abnormal genes. However, Lisa Schlager, Vice President of community affairs and public policy for FORCE (Facing Our Risk of Cancer Empowered), told CNN, “This new information may mean that that estimate is low.” FORCE is a national nonprofit organization dedicated to fighting hereditary breast, ovarian, and related cancers.
Schlager calls upon health systems to “embrace the ability to use genetic information to tailor healthcare by providing affordable access to the needed screening and preventive interventions.” As precision therapy and genetic analysis continue to shape the way patients are treated, medical laboratories will play a significant role in providing the information powering these innovative approaches.
Furthermore, medical laboratories might leverage the same methods used by researchers to assess risk factors and identify genetic mutations and markers associated with other cancers. Douglas Easton, PhD, Director of the Centre for Cancer Genetic Epidemiology within the Department of Public Health and Primary Care at the University of Cambridge, and leader of the OncoArray Consortium investigation, explained to CNN that Illumina’s Infinium OncoArray is not limited to breast cancer, but is designed to work with other cancers, including:
· ovarian; and,
· prostate cancers.
Identifying Women at Increased Risk for Breast Cancer
Peter Kraft, PhD, Professor of Epidemiology at Harvard’s T.H. Chan School of Public Health, and a study author, told CNN, “Taken together, these risk variants may identify a small proportion of women who are at three-times increased risk of breast cancer.”
Kraft notes that samples were sourced from women of primarily European ancestry. Further study of other ethnic populations could lead to yet more mutations and indicators for cancers more common outside of the European region.
Research authors also highlight the importance of continued standard screening, such as mammograms. However, they suggest that genetic mutations, such as those found in the OncoArray study, might be used to highlight high-risk individuals and screen sooner, or conduct more in-depth genetic analyses, to catch potential cancer cases earlier and improve outcomes.
“Many women are offered mammogram screening when they are middle-aged,” Georgia Chenevix-Trench, PhD, co-author of the Nature Genetics study and researcher at the QIMR Berghofer Medical Research Institute in Australia, told LabRoots. “But if we know a woman has genetic markers that place her at higher risk of breast cancer, we can recommend more intensive screening at a younger age.”
Anatomic pathologists and clinical laboratories can use these new insights to offer increased options for oncologists and physicians on the front lines of the battle against cancer. While the list of genetic mutations related to cancer is far from complete, each added mutation holds the potential to power a new treatment, improve early detection rates, and improve survival rates of this global killer.
Major Study of Genetics of Breast Cancer Provides Clues to Mechanisms Behind the Disease
Breast Cancer Genetics Revealed: 72 New Mutations Discovered in Global Study
Identification of Ten Variants Associated with Risk of Estrogen-Receptor-Negative Breast Cancer
Association Analysis Identifies 65 New Breast Cancer Risk Loci
An Unprecedented Study Has Revealed 72 New Breast Cancer Gene Variants
Study Finds 72 New Genetic Mutations Linked to Breast Cancer
Major Study Identifies 72 New Genetic Risk Factors for Breast Cancer
Breast Cancer: 72 New Gene Mutations Uncovered
Once thought to be separate components, the new model of a contiguous mesentery could lead to new medical laboratory tools for diagnosing and treating digestive diseases such as Crohn’s and colorectal cancer
For more than a century, pathology professionals have treated the network of tissue folds surrounding the human digestive system, known as the mesentery, as separate entities. However, new research indicates the mesentery is in fact a single, continuous organ and therefore reverses that thinking. This could impact the way pathologists and medical laboratories currently perform diagnostics and testing of digestive diseases.
Dr. J. Calvin Coffey, Professor of Surgery at the University of Limerick, Ireland, and Dr. Peter O’Leary, PhD, MBBS, of the Royal College of Surgeons in Ireland (RCSI), published their findings in The Lancet Gastroenterology and Hepatology. (more…)
The Technion breathalyzer would give pathology groups and medical laboratories unprecedented ability to support physicians in diagnosing and treating cancers, chronic diseases, and other illnesses
Readers of Dark Daily know that several pathology research teams in America and the UK are developing breath analyzer tests that can detect everything from lung cancer to early-stage infections. Clinical laboratories will soon have a plethora of breath-related tests from which to choose. Now there’s a new kid on the block. A breathalyzer test that can detect up to 17 distinct cancerous, inflammatory, and neurological diseases!
Assuming the cost per test was at a competitive level to existing technologies, what would give this new diagnostic system appeal to physicians and patients alike is that it would be a non-invasive way to diagnose disease. Only a sample of the patient’s breath would be needed to perform the assays.
Researchers at the Israel Institute of Technology, or Technion, published the results of their study in ACS Nano, a monthly journal of the American Chemical Society devoted to “nanoscience and nanotechnology research at the interfaces of chemistry, biology, materials science, physics, and engineering.” (more…)
Authors of the published study wrote that use of HD optical technology during colonoscopies gives patients a faster answer and may eliminate the need to refer biopsies to pathologists
High definition optical technology is reaching the point where gastroenterologists are able to identify pre-cancerous polyps with 96% accuracy during colonoscopies, according to a recent study conducted at the Mayo Clinic. Pathologists will want to pay close attention to the published findings of this study. That’s because GI biopsies represent a significant proportion of specimens referred to anatomic pathologists.
Researchers at Mayo Clinic worked with high-definition (HD) imaging systems, such as the Olympus Evis Exera II 180 and the Evis Exera III CV-190. The study was published in the June 24, 2014 issue of Gastrointestinal Endoscopy. (more…)