Guardant Health; Getty Images; Alyssa Powell/BI
- Guardant Health has the first FDA-approved liquid biopsy that can spot colon cancer.Co-CEO Helmy Eltoukhy tells Business Insider the story of how they used Silicon Valley strategy to build it.This article is part of "Transforming Treatments," a series on medical innovations that save time, money, or discomfort.
At first, cancer is a quiet disease. Inside the body, cells are aggressively multiplying out of control, changing everything. But on the outside, there's nothing special to see or feel. Not yet.
For Guardant co-CEO Helmy Eltoukhy, that invisibility looked like an engineering challenge. What if cancer could be detected early — through blood tests — before you even knew it was there?
"So many patients go through this really nerve-racking diagnostic odyssey," Eltoukhy told Business Insider.
Eltoukhy, who trained as an electrical engineer at Stanford during the late '90s dot-com boom, had watched classmates start companies like Google and Facebook. He took a job at Illumina, working to make genome sequencing cheaper — cutting the cost of a once-unthinkable endeavor from billions to around $1,000.
It was a lesson in how Moore's Law — technology getting exponentially faster and cheaper — could transform biology, too.
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And so, for the past 13 years, he's been chasing what he calls a holy grail for early disease detection: a blood test any doctor might whip out at an annual physical, to screen for all kinds of cancer.
Today, he's closer than ever. With FDA approval to screen for colon cancer already locked in, he's chasing pre-cancer detection, and maybe even general organ health and blood tests for other diseases, like inflammatory issues.
Still, it's unclear whether his publicly traded company will manage to turn a profit, and just how far its blood-based disease-hunting strategy can go.
Engineering blood to find cancer seemed easy, until it wasn't
A drop of blood that can detect disease? I know, we've heard this tall tale before (Theranos, anyone?) Technically, it's not impossible, if done right.
That's where Eltoukhy started. In 2012, he teamed up with fellow Stanford alum AmirAli Talasaz to design "liquid biopsies" — using fragments of cancer DNA in someone's blood to help doctors determine the best course of treatment.
Guardant used more than a drop's worth of blood, gathering a few teaspoons, enough to fill at least two vials. The company's first "360" cancer test was a success and was approved by the FDA in 2020, helping doctors better tailor late-stage cancer treatments and improve survival.
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But the ultimate goal was spotting cancer early — perhaps even before symptoms arise. In 2015, they "hit a wall," Eltoukhy said. Just a couple of years into their project, they found "there was nothing else to detect" genetically.
The company went into moonshot mode ("project LUNAR"), turning to epigenetics — the molecular "software" that controls which genes are powered on or off inside our bodies' hardware (our DNA).
That was the big unlock for seeing more cancer. "We created a chemistry that allows us to see both the hardware layer (the genomics) and the software layer (the epigenetics)," Eltoukhy said.
Suddenly, a whole new field of possibilities opened up.
From colon cancer to 'an everything test'
That breakthrough led to SHIELD, the first FDA-approved blood test for colon cancer, cleared in 2024. The test is near-perfect at detecting late-stage cancer, when there is a lot of cancer DNA being shed into a person's blood, but it is only about 60% sensitive to stage 1 cancer.
It is now being tested in a massive, independent clinical trial of 24,000 patients across the US, alongside a test from competitor ClearNote Health. The goal of this "Vanguard" study from the National Institutes of Health is to measure how well Guardant's SHIELD can spot not just colon cancer but other kinds, too — bladder, breast, pancreatic, and more.
"Think of it as your iPhone, where initially it only had a few features, over time, it has a thousand features," Eltoukhy told Business Insider. "You imagine a future where you combine all of that in a single blood test and you're looking at not billions, but trillions or quadrillions of data points per test. It's just a matter of time. There's no doubt in my mind that that'll be in the cards for all of us."
There's potential to detect other conditions, too. Inflammatory diseases, organ health, and biological aging are just a few of the targets Eltoukhy has his sights set on. "I think in the future it could be multi-disease," he said. "We think it could literally be an everything test that complements a primary care physician."
Today, liquid biopsies, like Guardant's, are among the most sought-after investments in biotech. Earlier this year, Guardant announced one such "strategic collaboration" with Pfizer. Guardant also has numerous publicly traded competitors, including the Illumina spinoff Grail, Myriad, and Natera.
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Dr. Eleftherios Diamandis, a clinical biochemist at the University of Toronto, has been studying the genetics of cancer since the 1980s. He says this kind of seamless cancer surveillance has always been a cancer doctor's dream, but so far, accurate early detection has remained elusive.
"I never say never because who knows how the science will work out in five years or 10 years," Diamandis told Business Insider. "But as we speak now with the clinical science Guardant has published and other companies have published, they are missing these lesions," he said, referring to the precancerous polyps that precede colon cancer, and that are easily cleaned out during routine colonoscopies.
Diamandis wonders if we will ever be able to reliably pick out meaningful clues in our blood that predate cancer — can you see something that's not there yet?
Still, he holds onto the possibility that science and technology might advance beyond what he can imagine. He never thought he'd be able to cruise through the chaos of rush hour traffic in a car that drives itself. Now, he does.
"The accuracy and the speed and all the difficult situations that this car can handle," he said. "I don't know how they made it. It's unbelievable."
The urgency
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Already, the demand for a test like SHIELD is high. Rates of colon cancer have been rising sharply among patients under 50, historically considered too young, too healthy, and too numerous for routine colonoscopies.
Dawson's Creek star James Van Der Beek, who was diagnosed with colon cancer at 46 years old, told Business Insider he wishes this test had been available years earlier. (Van Der Beek is now a paid spokesperson for Guardant.)
"If I could save anybody the journey that I've had to endure the last two years, man, that's a beautiful thing," Van Der Beek told Business Insider. "I mean, listen, the 'could-have, should-have' train is a black hole, and so I don't want to jump on board that, but don't let my could-haves become yours. That's my biggest message. Get screened."
