Best of all, the researchers say the test could provide an inexpensive means of early diagnosis. This assay could also be used to monitor how well patients respond to cancer therapy, according to a news release.
The protein had previously been identified as a promising biomarker and is readily detectable in tumor tissue, they wrote. However, it is found in extremely low concentrations in blood plasma and is “well below detection limits of conventional clinical laboratory methods,” they noted.
To overcome that obstacle, they employed an ultra-sensitive immunoassay known as a Simoa (Single-Molecule Array), an immunoassay platform for measuring fluid biomarkers.
“We were shocked by how well this test worked in detecting the biomarker’s expression across cancer types,” said lead study author gastroenterologist Martin Taylor, MD, PhD, Instructor in Pathology, Massachusetts General Hospital and Harvard Medical School, in the press release. “It’s created more questions for us to explore and sparked interest among collaborators across many institutions.”
“We’ve known since the 1980s that transposable elements were active in some cancers, and nearly 10 years ago we reported that ORF1p was a pervasive cancer biomarker, but, until now, we haven’t had the ability to detect it in blood tests,” said pathologist and study co-author Kathleen Burns, MD, PhD (above), Chair of the Department of Pathology at Dana-Farber Cancer Institute and a Professor of Pathology at Harvard Medical School, in a press release. “Having a technology capable of detecting ORF1p in blood opens so many possibilities for clinical applications.” Clinical laboratories may soon have a new blood test to detect multiple types of cancer. (Photo copyright: Dana-Farber Cancer Institute.)
Simoa’s Advantages
In their press release, the researchers described ORF1p as “a hallmark of many cancers, particularly p53-deficient epithelial cancers,” a category that includes lung, breast, prostate, uterine, pancreatic, and head and neck cancers in addition to the cancers noted above.
“Pervasive expression of ORF1p in carcinomas, and the lack of expression in normal tissues, makes ORF1p unlike other protein biomarkers which have normal expression levels,” Taylor said in the press release. “This unique biology makes it highly specific.”
Simoa was developed at the laboratory of study co-author David R. Walt, PhD, the Hansjörg Wyss Professor of Bioinspired Engineering at Harvard Medical School, and Professor of Pathology at Harvard Medical School and Brigham and Women’s Hospital.
The Simoa technology “enables 100- to 1,000-fold improvements in sensitivity over conventional enzyme-linked immunosorbent assay (ELISA) techniques, thus opening the window to measuring proteins at concentrations that have never been detected before in various biological fluids such as plasma or saliva,” according to the Walt Lab website.
Simoa assays take less than two hours to run and require less than $3 in consumables. They are “simple to perform, scalable, and have clinical-grade coefficients of variation,” the researchers wrote.
Study Results
Using the first generation of the ORF1p Simoa assay, the researchers tested blood samples of patients with a variety of cancers along with 406 individuals, regarded as healthy, who served as controls. The test proved to be most effective among patients with colorectal and ovarian cancer, finding detectable levels of ORF1p in 58% of former and 71% of the latter. Detectable levels were found in patients with advanced-stage as well as early-stage disease, the researchers wrote in Cancer Discovery.
Among the 406 healthy controls, the test found detectable levels of ORF1p in only five. However, the control with the highest detectable levels, regarded as healthy when donating blood, “was six months later found to have prostate cancer and 19 months later found to have lymphoma,” the researchers wrote.
They later reengineered the Simoa assay to increase its sensitivity, resulting in improved detection of the protein in blood samples from patients with colorectal, gastroesophageal, ovarian, uterine, and breast cancers.
The researchers also employed the test on samples from 19 patients with gastroesophageal cancer to gauge its utility for monitoring therapeutic response. Although this was a small sample, they found that among 13 patients who had responded to therapy, “circulating ORF1p dropped to undetectable levels at follow-up sampling.”
“More Work to Be Done”
The Simoa assay has limitations, the researchers acknowledged. It doesn’t identify the location of cancers, and it “isn’t successful in identifying all cancers and their subtypes,” the press release stated, adding that the test will likely be used in conjunction with other early-detection approaches. The researchers also said they want to gauge the test’s accuracy in larger cohorts.
“The test is very specific, but it doesn’t tell us enough information to be used in a vacuum,” Walt said in the news release. “It’s exciting to see the early success of this ultrasensitive assessment tool, but there is more work to be done.”
More studies will be needed to valid these findings. That this promising new multi-cancer immunoassay is based on a clinical laboratory blood sample means its less invasive and less painful for patients. It’s a good example of an assay that takes a proteomic approach looking for protein cancer biomarkers rather than the genetic approach looking for molecular DNA/RNA biomarkers of cancer.
Norwegian researchers reviewed large clinical trials of six common cancer screenings, including clinical laboratory tests, but some experts question the findings
Cancer screenings are a critical tool for diagnosis and treatment. But how much do they actually extend the lives of patients? According to researchers at the University of Oslo in Norway, not by much. They recently conducted a review and meta-analysis of 18 long-term clinical trials, five of the six most commonly used types of cancer screening—including two clinical laboratory tests—and found that with few exceptions, the screenings did not significantly extend lifespans.
The 18 long-term clinical trials included in the study were randomized trials that collectively included a total of 2.1 million participants. Median follow-up periods of 10 to 15 years were used to gauge estimated lifetime gain and mortality.
“The findings of this meta-analysis suggest that current evidence does not substantiate the claim that common cancer screening tests save lives by extending lifetime, except possibly for colorectal cancer screening with sigmoidoscopy,” the researchers wrote in their published paper.
The researchers noted, however, that their analysis does not suggest all screenings should be abandoned. They also acknowledged that some lives are saved by screenings.
“Without screening, these patients may have died of cancer because it would have been detected at a later, incurable stage,” the scientists wrote, MedPage Today reported. “Thus, these patients experience a gain in lifetime.”
Still, some independent experts questioned the validity of the findings.
Gastroenterologist Michael Bretthauer, MD, PhD (above), a professor at the University of Oslo in Norway led the research into cancer screenings. In their JAMA Internal Medicine paper, he and his team wrote, “The findings of this meta-analysis suggest that colorectal cancer screening with sigmoidoscopy may extend life by approximately three months; lifetime gain for other screening tests appears to be unlikely or uncertain.” How their findings might affect clinical laboratory and anatomic pathology screening for cancer remains to be seen. (Photo copyright: University of Oslo.)
Pros and Cons of Cancer Screening
The clinical trials, according to MedPage Today and Oncology Nursing News covered the following tests:
Mammography screening for breast cancer (two trials).
As reported in these trials, “colorectal cancer screening with sigmoidoscopy prolonged lifetime by 110 days, while fecal testing and mammography screening did not prolong life,” the researchers wrote. “An extension of 37 days was noted for prostate cancer screening with prostate-specific antigen testing and 107 days with lung cancer screening using computed tomography, but estimates are uncertain.”
The American Cancer Society (ACS) recommends certain types of screening tests to detect cancers and pre-cancers before they can spread, thus improving the chances for survival.
The ACS advises screenings for breast cancer, colorectal cancer, and cervical cancer regardless of whether the individual is considered high risk. Lung cancer screenings are advised for people with a history of smoking. Men who are 45 to 50 or older should discuss the pros and cons of prostate cancer screening with their healthcare providers, the ACS states.
A CNN report about the University of Oslo study noted that the benefits and drawbacks of cancer screening have long been well known to doctors.
“Some positive screening results are false positives, which can lead to unnecessary anxiety as well as additional screening that can be expensive,” CNN reported. “Tests can also give a false negative and thus a false sense of security. Sometimes too, treatment can be unnecessary, resulting in a net harm rather than a net benefit, studies show.”
In their JAMA paper, the University of Oslo researchers wrote, “The critical question is whether the benefits for the few are sufficiently large to warrant the associated harms for many. It is entirely possible that multicancer detection blood tests do save lives and warrant the attendant costs and harms. But we will never know unless we ask,” CNN reported.
Hidden Impact on Cancer Mortality
ACS Chief Scientific Officer William Dahut, MD, told CNN that screenings may have an impact on cancer mortality in ways that might not be apparent from randomized trials. He noted that there’s been a decline in deaths from cervical cancer and prostate cancer since doctors began advising routine testing.
“Cancer screening was never really designed to increase longevity,” Dahut said. “Screenings are really designed to decrease premature deaths from cancer.” For example, “if a person’s life expectancy at birth was 80, a cancer screening may prevent their premature death at 65, but it wouldn’t necessarily mean they’d live to be 90 instead of the predicted 80,” CNN reported.
Dahut told CNN that fully assessing the impact of cancer screenings on life expectancy would require a clinical trial larger than those in the new study, and one that followed patients “for a very long time.”
“From its title, one would have expected this paper to be based on analysis of individual lifetime data. However, it is not,” he wrote in a compilation of expert commentary from the UK’s Science Media Center. “The paper’s conclusions are based on arithmetic manipulation of relative rates of all-cause mortality in some of the screening trials. It is therefore difficult to give credence to the claim that screening largely does not extend expected lifetime.”
He also questioned the inclusion of one particular trial in the University of Oslo study—the Canadian National Breast Screening Study—“as there is now public domain evidence of subversion of the randomization in this trial,” he added.
Another expert, Leigh Jackson, PhD, of the University of Exeter in the UK, described the University of Oslo study as “methodologically sound with some limitations which the authors clearly state.”
But he observed that “the focus on 2.1 million individuals is slightly misleading. The study considered many different screening tests and 2.1 million was indeed the total number of included patients, however, no calculation included that many people.”
Jackson also characterized the length of follow-up as a limitation. “This may have limited the amount of data included and also not considering longer follow-up may tend to underestimate the effects of screening,” he said.
This published study—along with the range of credible criticisms offered by other scientists—demonstrates how analysis of huge volumes of data is making it possible to tease out useful new insights. Clinical laboratory managers and pathologists can expect to see other examples of researchers assembling large quantities of data across different areas of medicine. This huge pools of data will be analyzed to determine the effectiveness of many medical procedures that have been performed for years with a belief that they are helpful.
Cellular healthcare is an approach that goes beyond clinical laboratory testing to identify the location of specific cancer cells and aid in treatment decisions
Advances in synthetic biology and genetic engineering are leading to development of bacterial biosensors that could eventually aid pathologists and clinical laboratories in diagnosis of many types of cancers.
One recent example comes from researchers at the University of California San Diego (UCSD) who worked with colleagues in Australia to engineer bacteria that work as “capture agents” and bind to tumorous material.
The KRAS gene is associated with colorectal cancer. The researchers named their development the Cellular Assay for Targeted CRISPR-discriminated Horizontal gene transfer (CATCH).
CATCH successfully detected cancer in the colons of mice. The researchers believe it could be used to diagnose cancers, as well as infections and other diseases, in humans as well, according to a UCSD news release.
“If bacteria can take up DNA, and cancer is defined genetically by a change in its DNA, then, theoretically, bacteria could be engineered to detect cancer,” gastroenterologist Daniel Worthley, PhD, a cancer researcher at Colonoscopy Clinic in Brisbane, Australia, told MedicalResearch.com. This research could eventually provide clinical laboratories and anatomic pathologists with new tools to use in diagnosing certain types of cancer. (Photo copyright: Colonoscopy Clinic.)
Tapping Bacteria’s Natural Competence
In their Science paper, the researchers acknowledged other synthetic biology achievements in cellular biosensors aimed at human disease. But they noted that more can be done by leveraging the “natural competence” skill of bacteria.
“Biosensors have not yet been engineered to detect specific extracellular DNA sequences and mutations. Here, we engineered naturally competent Acinetobacter baylyi (A. baylyi) to detect donor DNA from the genomes of colorectal cancer cells, organoids, and tumors,” they wrote.
“Many bacteria can take up DNA from their environment, a skill known as natural competence,” said Rob Cooper, PhD, co-first author of the study and a scientist at US San Diego’s Synthetic Biology Institute, in the news release. A. baylyi is a type of bacteria renowned for success in doing just that, the NCI article pointed out.
This enabled them to explore “free-floating DNA sequences on a genomic level.”
Those sequences were compared to “known cancer DNA sequences.”
A. baylyi (genetically modified) was tested on its ability to detect “mutated and healthy KRAS DNA.”
Only bacteria that had “taken up mutated copies of KRAS … would survive treatment with a specific drug.”
“It was incredible when I saw the bacteria that had taken up the tumor DNA under the microscope. The mice with tumors grew green bacterial colonies that had acquired the ability to be grown on antibiotic plates,” said Josephine Wright, PhD, Senior Research Fellow, Gut Cancer Group, South Australian Health and Medical Research Institute (SAHMRI), in the news release.
Detecting DNA from Cancer Cells In Vitro and in Mice
Findings in vitro and in mice include the following:
The engineered bacteria enabled detection of DNA with KRAS G12D from colorectal cancer cells made in the lab, NCI reported.
When mice were injected with colorectal cancer cells, the researchers’ technology found tumor DNA, Engadget reported.
The study adds to existing knowledge of horizontal gene transfer from bacteria to bacteria, according to UCSD.
“We observed horizontal gene transfer from the tumor to the sensor bacteria in our mouse model of colorectal cancer. This cellular assay for targeted, CRISPR-discriminated horizontal gene transfer (CATCH) enables the biodetection of specific cell-free DNA,” the authors wrote in Science.
“Colorectal cancer seemed a logical proof of concept as the colorectal lumen is full of microbes and, in the setting of cancer, full of tumor DNA,” gastroenterologist Daniel Worthley, PhD, a cancer researcher at Colonoscopy Clinic in Brisbane, Australia, told MedicalResearch.com.
Finding More Cancers and Treatment
More research is needed before CATCH is used in clinical settings. The scientists are reportedly planning on adapting CATCH to multiple bacteria that can locate other cancers and infections.
“The most exciting aspect of cellular healthcare … is not in the mere detection of disease. A laboratory can do that,” wrote Worthley in The Conversation. “But what a laboratory cannot do is pair the detection of disease (a diagnosis) with the cells actually responding to the disease [and] with appropriate treatment.
“This means biosensors can be programmed so that a disease signal—in this case, a specific sequence of cell-free DNA—could trigger a specific biological therapy, directly at the spot where the disease is detected in real time,” he added.
Clinical laboratory scientists, pathologists, and microbiologists may want to stay abreast of how the team adapts CATCH, and how bacterial biosensors in general continue to develop to aid diagnosis of diseases and improve ways to target treatment.
The focus of the ongoing GenoVA study is to “determine the clinical effectiveness of polygenic risk score testing among patients at high genetic risk for at least one of six diseases measured by time-to-diagnosis of prevalent or incident disease over 24 months,” according to the National Institutes of Health.
The scientists used data obtained from 36,423 patients enrolled in the Mass General Brigham Biobank. The six diseases they researched were:
The polygenic scores were then tested among 227 healthy adult patients to determine their risk for the six diseases. The researchers found that:
11% of the patients had a high-risk score for atrial fibrillation,
7% for coronary artery disease,
8% for diabetes, and
6% for colorectal cancer.
Among the subjects used for the study:
15% of the men in the study had a high-risk score for prostate cancer, and
13% of the women in the study had a high score for breast cancer.
The researchers concluded that the implementation of PRS may help improve disease prevention and management and give doctor’s a way to assess a patient’s risk for these conditions. They published their findings in the journal Nature Medicine, titled, “Development of a Clinical Polygenic Risk Score Assay and Reporting Workflow.”
“We have shown that [medical] laboratory assay development and PRS reporting to patients and physicians are feasible … As the performance of PRS continues to improve—particularly for individuals of underrepresented ancestry groups—the implementation processes we describe can serve as generalizable models for laboratories and health systems looking to realize the potential of PRS for improved patient health,” the researchers wrote.
Using PRS in Clinical Decision Support
Polygenetic risk scores examine multiple genetic markers for risk of certain diseases. A calculation based on hundreds or thousands of these genetic markers could help doctors and patients make personalized treatment decisions, a core tenet of precision medicine.
“As a primary care physician myself, I knew that busy physicians were not going to have time to take an entire course on polygenic risk scores. Instead, we wanted to design a lab report and informational resources that succinctly told the doctor and patient what they need to know to make a decision about using a polygenic risk score result in their healthcare,” epidemiologist Jason Vassy, MD, told The Harvard Gazette. Vassy is Associate Professor, Harvard Medical School at VA Boston Healthcare System and one of the authors of the research.
“This is another great example of precision medicine,” Jason Vassy, MD (above), Adjunct Assistant Professor, General Internal Medicine at Boston University School of Medicine, told WebMD. “There’s always been a tantalizing idea that someone’s genetic makeup might help tailor preventative medicine and treatment.” Personalized clinical laboratory testing is increasingly becoming based on an individual’s genetics. (Photo copyright: Harvard Medical School.)
Increasing Diversity of Patients in Genomic Research
The team did encounter some challenges during their analysis. Because most existing genomic research was performed on persons of European descent, the risk scores are less accurate among non-European populations. The researchers for this study addressed this limitation by applying additional statistical methods to qualify accurate PRS calculations across multiple racial groups.
“Researchers must continue working to increase the diversity of patients participating in genomics research,” said Matthew Lebo, PhD, Chief Laboratory Director, Laboratory Molecular Medicine, at Mass General Brigham and one of the authors of the study. “In the meantime, we were heartened to see that we could generate and implement valid genetic scores for patients of diverse backgrounds,” he told The Harvard Gazette.
The team hopes the scores may be utilized in the future to help doctors and patients make better decisions regarding preventative care and screenings.
“It’s easy to say that everyone needs a colonoscopy at age 45,” Vassy told WebMD. “But what if you’re such a low risk that you could put it off for longer? We may get to the point where we understand risk so much that someone may not need one at all.”
Future of PRS in Clinical Decision Making
The scientists plan to enroll more than 1,000 patients in a new program and track them for two years to assess how medical professionals use PRS in clinical care. It is feasible that patients who are at high risk for certain diseases may opt for more frequent screenings or take preventative medicines to mitigate their risk.
“Getting to that point will take time,” Vassy added. “But I can see this type of information playing a role in shared decision making between doctor and patient in the near future.”
The team also established resources and educational materials to assist both doctors and patients in using the scores.
“It’s still very early days for precision prevention,” Vassy noted, “but we have shown it is feasible to overcome some of the first barriers to bringing polygenic risk scores into the clinic.”
More research and studies are needed to prove the effectiveness of using PRS tests in clinical care and determine its role in customized treatment plans based on personal genetics. Nevertheless, pathologists and medical scientists will want to follow the GenoVA study.
“It is probably most helpful to think of polygenic risk scores as a risk factor for disease, not a diagnostic test or an indication that an individual will certainly develop the disease,” Vassy said. “Most diseases have complex, multifactorial etiologies, and a high polygenic risk score is just one piece of the puzzle.”
Pathologists and clinical laboratory managers may want to stay informed as researchers in the GenoVA study tease new useful diagnostic insights from their ongoing study of the whole human genome. Meanwhile, the GenoVA team is moving forward with the 1,000-patient study with the expectation that this new knowledge may enable earlier and more accurate diagnoses of the health conditions that were the focus of the GenoVA study.
GI pathologists will be interested in how the Endoculus device uses tank-like treads to traverse the gastrointestinal tract, where it can capture images and perform biopsies
Gastroenterologists (GI) may soon gain a useful new tool for use in gathering both biopsies and diagnostic information when examining the gastrointestinal tract. Ongoing development of a new robotic device promises both capabilities using technology that will be of interest to GI pathologists and clinical laboratory scientists.
The minute robotic device uses tank-like treads to traverse the colon. While there, it can capture live images and perform biopsies under the control of a gastroenterologist. The researchers believe the robotic technology will benefit GIs performing the colonoscopies as well as the pathologists called upon to analyze biopsies.
“Currently, endoscopy consists of a gastroenterologist using a semi-rigid, long rope-like device and endoscope to propel through your colon manually,” Gregory Formosa, PhD (above) a member of the AMTL team that developed Endoculus, said in a YouTube video describing the device. “We think that a robotic capsule endoscope can replace conventional endoscopes by making them faster, safer, and more robust than a human operator can do currently with traditional techniques,” he added. (Photo copyright: University of Colorado.)
AMTL researcher Gregory Formosa, PhD, said the team’s goal is to “have a capsule-sized robot that can actively traverse [a patient’s] entire gastrointestinal tract and send out diagnostics in real time, as well as autonomously navigate itself to localize problematic areas within [the] intestinal tract.”
Formosa noted that colorectal cancer is “the third-most fatal and diagnosed cancer in the United States.” But if caught at an early stage, these cancers are “95% treatable,” he added. “So, if we can get people screened early, we definitely can reduce the fatality rate of colorectal cancers significantly.”
Currently about the size of a C battery, Endoculus (above) is a “fully packed medical device, complete with a camera, an air pump for inflating the colon, a water pump for cleaning, and a tool port for holding biopsy snares,” states a University of Colorado news story, titled, “A Robot May One Day Perform Your Colonoscopy.” (Photo copyright: University of Colorado.)
How Endoculus Works
One key to the device are the four treads, which are designed for traction on digestive tissue.
“You have to forget about everything you know from a locomotion standpoint because driving around inside the body is very different than driving around in a car,” said Rentschler in the University of Colorado news story. “The environment is highly deformable. It’s very slick. There are sharp peaks that you have to go over.”
The university news story noted the current availability of ingestible “pill cams” that can take photos as they travel through the digestive system. But once swallowed, their movements cannot be controlled.
“For our robots to be able to reach those regions that [can be] reached with a pill-cam—but also be able to stop and look around—that could be a big paradigm shift in the way we view these procedures,” said Micah Prendergast, PhD, an AMTL research team member.
Could Biopsies Be Diagnosed In Situ with Endoculus?
The researchers currently view Endoculus as a potentially better way to perform conventional biopsies. But could it lead to bigger advancements?
“Researchers continue to develop devices to help various specialist physicians—in this case GIs—do more when treating patients,” said Dark Daily Publisher and Editor-in-Chief Robert Michel. “This device fits that description. It is designed to improve the ability of GIs to evaluate the colon. Not only does this device do that, but it can also collect a biopsy at sites of interest. In this way, it is a device that can be a benefit to pathologists who will analyze the biopsy.
“With improvements in digital cameras and associated AI-powered analytical tools, the day might not be far off when a device like this can use the camera and artificial intelligence to diagnose the tissue of interest in situ,” he added. “This might create the opportunity for pathologists to be present in the exam room during the procedure, or even viewing the images remotely.
“Not only would that eliminate the need to collect a tissue specimen that must then be sent to a pathology lab, but it would create a new opportunity for pathologists to add value to patient care while shortening the time to diagnosis for the tissue of interest during these procedures,” Michel noted.
