Liquid Biopsy: “the future of cancer detection”
WHAT IS BIOPSY?
Biopsy means the technique of extraction of tissue . In brief, this diagnostic test involves extraction of some cells/ tissue to diagnose the presence or extent of disease.
This technique is mainly used for the detection of cancer . Depending on the condition, the doctor extracts a piece of tissue, skin , organ or tumour to analyse the condition.
HOW BIOPSY IS DONE?
The procedure of biopsy includes:
- mark the area to be biopsied
- clean the area
- Anaesthetise the Skin
- extract the tissue/cells/organ/tumour
- bandage
The following are the various types of biopsy procedures used to make a cancer diagnosis:
- bone marrow biopsy
- endoscopic biopsy
- needle biopsy
- skin biopsy
- surgical biopsy
But as this method is invasive and is often high risk procedure ,because sometimes accessing some areas especially around major vessels can present a safety risk. Also sometimes the tissue is inaccessible due to its anatomical location like mid lung. And, Moroever this technique is used only when a patient is having symptoms ,which makes it difficult to detect cancer in early stages.
So, there is a high call for a new technique to detect cancer and that too in early stage in routine investigations that is “LIQUID BIOPSY”
LIQUID BIOPSY
Overview
Liquid biopsy is the study or analysis of non-solid biological tissue especially blood to look for cancer cells from a tumor that are circulating in the blood or for pieces of DNA from tumor cells.
What exactly is cancer?
Cancer is the uncontrolled growth of abnormal cells and when these cells accumulate they form tumor. With cancer and other tumors, something disrupts the cycle of natural death and production of cells. Tumor cells grow, even though the body does not need them, and unlike normal old cells, they don’t die. Cancer has the ability to spread throughout the body by metastasis and can harm our normal tissues.
Cancer is the second leading cause of death in the world and still we don’t have a perfect cure for it.
Liquid biopsy in cancer detection
When tumor develops in a particular part of body the blood vessels becomes leaky there so some fragments or elements are released by tumour.
There are mainly two types of cancer-derived material that are released in blood :
1. CTC s(CIRCULATING CANCER CELLS)
2. ctDNA(CELL FREE CIRCULATING TUMOR DNA)
When the amount of CTCs increase the no. of phagocytes also increase to clear apoptotic and necrotic fragments, resulting in the release of passive ctDNA.
Physicians use these to highly reflect the following information about tumor:
- RNA and protein expression
2. DNA and chromosomal abnormalities
3. Amplification, deletions, and translocations
4. Point mutations
LIQUID BIOPSY vs NORMAL BIOPSY
How the technology is being used today and what companies are pioneering it?
The genetic information provided by tumor biomolecules offers insight into the tumor. This information is used in many ways by the doctors like:
- disease prognosis
- treatment
- post cancer effects
- Measuring a cancer’s response to treatments
- Looking for cancer relapse post-treatment
As liquid biopsy is relatively new technique, there is constant study going on in this field and scientists are trying to find more and more information about tumor.
Companies :
- INIVATA:
Their technology
Inivata has developed some of the most sensitive techniques available to detect this ctDNA and identify a broad range of disease-specific mutations.
According to their WEBSITE,
Once collected, the blood sample is centrifuged to separate the plasma containing the cell-free DNA from other components. The DNA is then extracted, amplified, and then analyzed for mutations.
Being able to analyze the liquid biopsy for multiple mutations simultaneously allows the clinician to better understand the tumor profile and adapt treatment appropriately.
.
Their solution:
Their test InVisionFirst -Lung, a ctDNA NGS liquid biopsy tests 37 genes relevant to the care of patients with advanced NSCLC.
2. GRAIL:
It is one of the biggest company leading the market of liquid biopsy by raising more than1 billion dollars.
THEIR AIM:
Their aim is to detect cancer in early stages. they believe in that way we can increase the survival rate by approximately 6 times. They are developing their test in a rigorous way to deliver our test to patients safely and effectively.
THEIR APPROACH:
To achieve this, we are building intelligent models to identify clinically actionable information from vast amounts of tumor genome data obtained through high-intensity sequencing. According to them,With the best talent in biology, clinical science, bioinformatics, deep learning, and engineering along with the passion of our leadership, our goal is to greatly decrease global cancer mortality.
What are the most recent advancements in the industry? Any big news?
- A revolution in cancer diagnostics is occurring using in vitro blood testing to identify cancer DNA. The technology has created the possibility of widespread screening for all types of cancers with a blood test.
GRAIL, a new company with impressive backing, has announced a single blood test to detect all cancers. The company is now working on a 10,000-plus subject study, called the Circulating Cell-Free Genome Atlas (CCGA) to help identify cancer early. The technology is moving faster than the market. New technology that definitively identifies disease conditions from blood samples is poised to replace expensive invasive surgical biopsy procedures.
The market is still in its infancy but has just moved out of the development phase and into the growth phase. The impact on the healthcare industry is enormous. The report forecasts the market size out to 2024. In addition, the report looks at potential market sizes by country, by cancer and by the four types of usage: screening, diagnosis, therapy selection and recurrence monitoring.
2. EISAI commences joint R & D of Cancer Gene Panel Test with Personal Genome Diagnostics:
In this joint research and development, Eisai and PGDx will create a kitted cancer gene panel test that enables a comprehensive analysis of mutation in more than 500 cancer gene using liquid biopsy with blood samples.
Advantages
- Non invasive method for cancer detection.
- Use of bio fluids causes less trauma to patients.
- It is generally less risk to patients who are not recommended for tissue biopsy.
- Signatures of patients’ tumors can be characterized molecularly; aids in understanding tumor biology and may be the best tool for monitoring therapeutic response and perhaps, early detection.
- Repeated sampling is possible.
- Early detection
- There is no risk of spillage of cancerous tissue which can cause metastasis in other parts of body during standard biopsy.
CHALLENGES
- Low levels of mutant ctDNA that is diluted in blood; thus requiring large volumes of blood.
- Low capture efficiency
- Issues with specificity
- It is not the representation of all genetic clones
- due to low volume of ctDNA there are chances of false negatives
Although, advances had been made in the detection of tumor disseminated components, Sensitivity, and Specificity remain important challenges. Ambiguity remains in how to interpret current findings and how liquid biopsy can be used in clinical practice.
CONCLUSION
Will liquid biopsy replace tissue biopsy?
With liquid biopsy there would be an early detection of disease hence resulting in better cure and outcome of the patient and in future with better with better sensitivity and specificity it is definitely going to replace tissue biopsy which gives diagnosis in later stages of disease.
The extent to which liquid biopsy might ultimately replace standard tissue biopsies is still unclear. For diagnosing primary tumours or determining the stage of metastatic lesions in tissues where it is difficult to extract a sample, liquid biopsy might provide a reliable alternative. Liquid biopsy could also help to avoid complications that occur after invasive tissue biopsy, such as bleeding, infections and pain.
Researchers have known about the clinical potential of liquid biopsies for many years. To push them into widespread use, more interventional clinical trials are now needed, as well as the development of an algorithm to combine the appropriate circulating biomarkers.
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