Tuesday January 28, 2020

Here’s How a New Blood Test Detects 20 Types of Cancers

A new blood test has shown ability to screen numerous types of cancer with a high degree of accuracy, test showed it detected and localized more than 20 types of cancers

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human, ageing, development, cancer, study
The researchers found that in most of the tissues examined, ageing and cancer gene expression 'surprisingly' changed in the opposite direction. Pixabay

A new blood test has shown ability to screen numerous types of cancer with a high degree of accuracy. A trial of the test showed it detected and localized more than 20 types of cancers.

The test, developed by biotechnology company Grail Inc uses next-generation sequencing technology to probe DNA for tiny chemical tags (methylation) that influence whether genes are active or inactive.

When applied to nearly 3,600 blood samples — some from patients with cancer and some from people who had not been diagnosed with cancer at the time of the blood draw — the test successfully picked up a cancer signal from the cancer patient samples, and correctly identified the tissue from where the cancer began (the tissue of origin),” said investigators from Boston-based Dana-Farber Cancer Institute.

The test’s specificity – its ability to return a positive result only when cancer is actually present – was high, as was its ability to pinpoint the organ or tissue of origin, they found.

The new test looks for DNA, which cancer cells shed into the bloodstream when they die.

In contrast to “liquid biopsies,” which detect genetic mutations or other cancer-related alterations in DNA, the technology focuses on modifications to DNA known as methyl groups.

Methyl groups are chemical units that can be attached to DNA, in a process called methylation, to control which genes are “on” and which are “off.”

Abnormal patterns of methylation turn out to be, in many cases, more indicative of cancer – and cancer type — than mutations are.

“Our previous work indicated that methylation-based assays outperform traditional DNA-sequencing approaches to detecting multiple forms of cancer in blood samples,” said the study’s lead author Geoffrey Oxnard from Dana-Farber.

cancer, health, science, blood test, types
A patient has her blood drawn at a hospital in Philadelphia to monitor her cancer treatment. VOA

“The results of the new study demonstrate that such assays are a feasible way of screening people for cancer,” Oxnard added.

Detecting even a modest percent of common cancers early could translate into many patients who may be able to receive more effective treatment if the test were in wide use, the study said.

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Dana-Farber Cancer Institute investigators presented the results of the trial during a session at the European Society for Medical Oncology (ESMO) 2019 Congress in Barcelona, Spain, on September 28. (IANS)

Next Story

Patients May Suffer Invasive Treatments for Harmless Cancers: Researchers

According to the researchers, It is the first time that the risk of overdiagnosis has been quantified across five cancers, anywhere in the world

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A breast cancer diagnosis is terrifying enough at any time. Pixabay

Researchers have revealed that Australians are increasingly being diagnosed with potentially harmless cancers, which if left undetected or untreated, may expose them to unnecessary surgeries and chemotherapy.

The research, published in the Medical Journal of Australia, drew on data from the Australian Institute of Health and Welfare to compare how the lifetime risk of five cancers had changed between 1982 and 2012.

The study shows compared to 30 years ago, Australians are much more likely to experience a cancer diagnosis in their lifetime.

“Cancer treatments such as surgery, radiotherapy, endocrine and chemotherapy carry risks of physical harms,” said the study authors from Bond University, University of Sydney and Griffith University in Australia.

“In the absence of overdiagnosis, these harms are generally considered acceptable. In the context of overdiagnosed cancers, however, affected individuals cannot benefit but can only be harmed by these treatments,” authors added.

The figures suggest that in 2012 24 per cent of cancers or carcinomas in men were overdiagnosed. These included 42 per cent of prostate cancers, 42 per cent of renal cancers, 73 per cent of thyroid cancers and 58 per cent of melanomas.

Cancer
Cancer Ribbon. Pixabay

For women, 18 per cent of cancers or carcinomas were overdiagnosed, including 22 per cent of breast cancers, 58 per cent of renal cancers, 73 per cent of thyroid cancers and 58 per cent of melanomas.

The figures are significant because of the harm that can occur from cancer treatment of patients who would never have had symptoms in their lifetime.

The authors also refer to separate studies showing overdiagnosis could be linked to psychological problems.

“For example, men’s risk of suicide appears to increase in the year after receiving a prostate cancer diagnosis,” researchers said.

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According to the researchers, It is the first time that the risk of overdiagnosis has been quantified across five cancers, anywhere in the world.”

The findings also suggest an important role for health services such as the Australian Institute of Health and Welfare, in detecting potential overdiagnosis and alerting health policy decision makers to the problem early on. (IANS)