Liquid Biopsy! This buzzword is being bandied around quite a bit these days. It’s the latest and supposedly a very important diagnostic test for cancer. How exactly, do you ask? Here goes.
Typically, a tissue sample of all kinds of cancers is required to understand the type and nature of cancer. This sample is known as a biopsy and is a chunk of the solid tumor. Now, getting a biopsy is easy if a tumor is accessible, for example if it is on the skin or just underneath the skin. Obtaining a biopsy is a minor surgery. Imagine, however, if a tumor were to be seen on the liver or pancreas or some other internal organ. In this case, getting a biopsy of the tumor is itself a risky and painful procedure. So, how do doctors get around this problem?
This is where liquid biopsy comes into its own. Most normal cells as well as tumor cells shed bits of their DNA into the blood when they die out as part of the normal tissue turnover process. Scientists have known about this for a few years now. What is exciting, now, is that there are ways to capture this DNA from the blood of a person and analyse it to see if there are signs of cancer present. So, thanks to these technological advances, we are able to obtain a chunk of the tumor (a biopsy) using a liquid tissue, namely blood. Hence the name: Liquid Biopsy.
At Strand Life Sciences, we have launched a set of Liquid Biopsy tests in April 2017. We have standardized the purification of DNA and the detection of cancer-related genetic mutations to a high degree of accuracy. In fact, our liquid biopsy products provided stellar results in a recent case.
A patient, from Hyderabad, was referred to us in August 2016. He had colorectal cancer and was set to undergo surgery. His doctors provided us a sample of the solid tumor as well as a 10 ml blood sample at the time of the surgery to remove his tumor.
A parallel analysis of both the solid and liquid biopsies was conducted to understand the genetic profile of the colorectal cancer. Scientists at Strand identified a characteristic mutation that was present in the solid tumor as well as in the liquid biopsy sample!
So, the liquid biopsy readouts mirrored those obtained from the solid tumor biopsy a 100%!
What this enabled us to do is to track the progress of the cancer and response to additional therapy, going further. Four months later, all the patient had to do was send us a blood sample in one of our special blood collection kits. So, in December, the liquid biopsy sample was again analysed to check for the ‘signature mutation’ of colorectal cancer that was identified earlier.
In December 2016, the signature mutation was NOT identified in the patient’s blood, indicating that possibly all the cancer tissue was removed during the surgery.
Just to be sure, another liquid biopsy sample was sought from the patient in April 2017. In the second round of analysis as well, the signature mutation of colorectal cancer was NOT detected in the blood sample.
Naturally, the patient as well as his oncologist are very elated about these results. If they were to rely on the results of a PET/CT scan to understand the status of cancer, there would have been a waiting period of at least six months post the surgery and other accessory therapies. Instead, a series of two liquid biopsies have provided the same answer very easily!
We aim to follow-up with this patient for another year, at the very least, until we have concrete assurance that his cancer has not returned.