This Startup Wants To Catch Cancer Before It Spreads

April 6, 2026

AI Summary

5 min read

The Needle in Three Billion Base Pairs

One in eleven babies born in America this year will be screened by a genetic test that didn't exist a decade ago. The company behind it, Billion to One, started with a half lab bench, $300,000, and a conviction that the standard approach to detecting rare DNA in blood was fundamentally wrong. Co-founders Ozan and David met as undergrads, pursued separate PhDs—Ozan at Stanford, David at Rice—and reunited when Ozan called David with an idea. Their insight was that the amplification process used in every genetic test introduces so much noise that the signal from rare DNA fragments gets lost. Their solution: add synthetic DNA molecules to the sample before amplification, measure exactly how the process distorts the data, and subtract that distortion computationally. As Ozan puts it, this "converts a difficult biology problem to almost a simple mathematical problem."

The Interdisciplinary Gap They Exploited

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What you'll learn

1 (00:00) **The Needle-in-a-Haystack Problem** - Billion to One's core challenge: detecting a single mutated base pair out of three billion in the human genome, and how the company's name originates from this ratio.
2 (01:25) **Company Origin Story** - Founders Ozan and David met as undergrads, reconnected during PhDs, and applied to YC in 2017 with the same core idea.
3 (03:17) **The Core Technical Breakthrough** - How synthetic DNA (QCTs) added before amplification removes noise and turns a biology problem into a math problem.
4 (05:24) **From PhD Idea to Commercial Test in Two Years** - The founders' background and the rapid development timeline.
5 (07:17) **The Early Struggles** - Starting with a half lab bench, $300K raised in tiny increments, and skepticism from suppliers.
6 (08:26) **Cracking the Sales Problem** - The emergency meeting that turned around adoption.
7 (09:49) **Lab Tour: The Processing Pipeline** - How samples move from raw blood to sequenced data.

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Show Notes

1 in 11 babies born in America this year will be screened by a genetic test that didn't exist a decade ago.Biotech startup BillionToOne turned a simple but radical idea—detecting rare fragments of fetal DNA in a mother's blood—into one of the most widely used prenatal tests in the U.S. And they're not stopping there. The same approach could unlock something even bigger: early-stage cancer detection from a blood test, a breakthrough that could one day save millions of lives.In this episode of Hard Tech, YC's Jared Friedman sits down with David Tsao and Oguzhan Atay to hear how they went from half a lab bench to a $4B biotech company—and why they believe this is just the beginning of what their technology can do.