The Blood Test Revolution: Remedy or Poison?
The prospect of a miracle blood test capable of identifying hundreds of diseases and genetic mutations in hours is a dream the world is not far from attaining. When Elizabeth Holmes, a Steve Jobs-esque Stanford dropout, claimed to have found the answer to this technological race, it was not a surprise that Silicon Valley investors rushed to her feet. Along Theranos’ path in the pursuit of success, fraudulent claims were made and data was falsified in a money-making frenzy. The idea had such a seductive power that Henry Kissinger to pharmacy chain Walgreens, and Larry Ellison skipped the traditional background checks. But despite a fraud of epic proportions, the Theranos tale was not enough to put off others from continuing to pursue the ‘El Dorado’. Whilst it remains hard to predict when biotech start-ups will succeed, if and when they do, the world of healthcare and early diagnosis will be shattered to their cores. But there is more to learn from the Theranos story: greed is lurking behind the blood test revolution.
In the field of cancer detection through liquid biopsy, the idea behind innovative methodologies is simple. A vial of blood is taken and centrifuged so that circulating fragments of cell-free DNA can be collected and screened for genetic mutations that may indicate certain cancers. If we imagine the normal replication of cells as bricks slowly building up a house, cancer is like throwing these bricks in a pile. The dust formed is known as circulating tumour DNA (ctDNA), which can subsequently be analysed. One of the main advantages of liquid biopsies is that they are much less invasive and pain free than traditional tissue biopsies—a process widely preferred by patients and doctors.
In the case of Theranos, the start-up chose to adopt immunoassays, identifying antibodies rather than DNA. The principle of extracting the changes made to blood during a disease and using these as markers is the same. To make the whole idea more tantalising, Theranos claimed that with one single drop of blood, not even a vial, was capable of identifying over 240 different diseases (including multiple forms of cancer) from the comfort of one’s own home. But behind a web of lies and falsehoods, the reality was one where the method required tireless work from engineers to produce results. When engineers raised concerns about the methods’ effectiveness and efficiency, they were sacked. By 2016, after a Wall Street Journal investigation revealed faulty results regarding harming patient safety, two years of Theranos blood tests were voided and the bubble burst.
Whilst Theranos failed, progress in harnessing the potential of blood tests has been steady in other areas. For example, genetic sequencing has rapidly improved in recent years, as illustrated by the Chinese government distributing the entire coronavirus genome in only one weekend. Liquid biopsies can also be used to rapidly identify early mutations in a given blood sample. This is done by comparing high-risk markers and mutations of specific cancers, like the protein HER2 in breast cancer, to a standard panel of what is normal. Progress is such that the NHS piloted liquid biopsies in 2021 to detect lung cancers.
As of today, liquid biopsies are particularly effective in identifying the later stages of cancer where they are easily able to detect tumour metastasis (meaning the tumour has spread around the body). The current challenge lies in being able to read the synergy of multiple circulating biomarkers, and thus interpreting the results as one molecular story to reveal the specifics of a cancer early on. A case in point is the European PROLIPSY project which aims to curate an algorithm for early prostate cancer detection. But there are many others.
In coda, technological progress in harnessing blood tests to speed up diagnosis of diseases, notably cancer, has been remarkable in recent years, even if the Theranos dream is far off. But with great power comes great responsibility. The more blood tests advance, the more caution needs to be taken with their diagnostic capabilities. The trivialisation of blood tests has unintended costs as they can lead to overly early cancer diagnoses which may create unnecessary emotional distress in cases where those cancers are unlikely to have a material impact during one’s life. New complications will emerge as uses for liquid biopsies predictive tests for cancer become more accessible like diagnosing diseases when there is no solution in our present. People may be better off not knowing about it at all. It is not by chance that in ancient Greek, the word “pharmakon” (translated as drug) means both remedy and poison. As the blood test industry progresses, hope that wisdom prevails rather than greed.
Photo: Bio Spectrum India
Works Cited:
Alix-Panabières, Catherine. 2020. “The future of liquid biopsy.” Nature. https://www.nature.com/articles/d41586-020-00844-5.
Kunthara, Sophia. 2021. “A Closer Look At Theranos' Big-Name Investors, Partners And Board As Elizabeth Holmes' Criminal Trial Begins.” Crunchbase News. https://news.crunchbase.com/health-wellness-biotech/theranos-elizabeth-holmes-trial-investors-board/.
NHS. 2020. “NHS England » NHS to pilot potentially revolutionary blood test that detects more than 50 cancers.” NHS England. https://www.england.nhs.uk/2020/11/nhs-to-pilot-potentially-revolutionary-blood-test/.
Stieg, Cory, and Andrew Harrer. 2019. “What Exactly Was The Theranos Edison Machine Supposed To Do?” Refinery29. https://www.refinery29.com/en-us/2019/03/224904/theranos-edison-machine-blood-test-technology-explained.