Catching cancer early is an incredible challenge, but a new way to detect it in the blood may totally revolutionize cancer treatment in just a few years.

Illumina, the $25 billion maker of gene sequencing technology, has created a new company to invent a blood test to detect all cancers in their early stages, something that would be a tremendous help to those trying to detect the illness before it is too difficult to treat effectively.

This isn't the first attempt of this nature, and previous efforts by other companies have been criticized for having too little research behind them or focusing too much on detection rather than treatment. Crucially, this blood test does not exist yet, and while scientists will be working furiously to try to make it happen, it doesn't mean they will succeed.

But this latest bet is one of the best-funded, with a number of illustrious scientists already involved — and Illumina's backing may give it a crucial boost.

The new company, called Grail (as in, it's trying to achieve something considered the Holy Grail for cancer researchers) hopes to have a pan-cancer blood test by 2019, an extremely ambitious goal.

That would mean that anyone could add such a test onto their annual physical — no need for separate tests for different types of lung cancer, prostate cancer, or any other form of the illness.

Bill Gates speaks on stage at the Plenary Session: Investing in Prevention and Resilient Health Systems during the second day of the 2015 Clinton Global Initiative's Annual Meeting at the Sheraton New York Hotel & Towers on September 27, 2015 in New York City. JP Yim/Getty Images

Grail is launching with $100 million in Series A financing, backed by Illumina, Bill Gates, Sutter Hill Ventures, and Jeff Bezos' Bezos Expeditions. Illumina and Memorial Sloan Kettering Cancer Center are partnering to help launch a study to see if Grail's test can actually do what they hope it will do.

"We look forward to a day in the not too distant future where there would be a simple blood test for every form of cancer," Dr. Richard Klausner, former director of the National Cancer Institute and a board member of Grail, said on a press call on Sunday.

The key to this effort is the ability to detect what's known as circulating tumor DNA, or CTDNA. In recent years, doctors have discovered that the genetic material from cancerous tumors starts circulating in our bodies.

"It's abundantly clear that these molecules are in the blood," Illumina CEO Jay Flatley said on the call.

So, along with Memorial Sloan Kettering, Grail plans on following hundreds of thousands of patients over the next few years and trying to see if they can detect CTDNA in those patients whenever they develop cancer.

That research will be crucial: An earlier effort by another company, Pathway Genomics, to create a "liquid biopsy" for cancer was greeted in September by a stern letter from the Food and Drug Administration (FDA) warning that the agency had "not found any published evidence that this test or any similar test has been clinically validated as a screening tool for early detection of cancer in high risk individuals."

Flatley is well aware of the minefield Grail is entering. "If you look at this business, it’s littered with failures. With a few exceptions, screening tests have been invariably horrible," he told the MIT Technology Review. "It’s a big challenge."

If Grail's trials show its test can detect stage 2 cancer, Flatley says the market value of those tests could be from $20 to $40 billion. If CTDNA can accurately identify stage 1 cancers, that would give them a $100 billion value, according to Flatley.

Doing something like this does also comes with risks for overdiagnosis, even if the research is successful; a regular test for cancer risks causing many people to receive potentially dangerous treatment for cancers that wouldn't have seriously impacted their health in the long run, according to José Baselga, Physician-in-Chief and Chief Medical Officer of Memorial Sloan Kettering.

But the ways that CTDNA screening could work, and the opportunities that screening creates for early treatment, could revolutionize cancer treatment in ways that "cannot be overemphasized," according to Baselga.

"We must diagnose cancer earlier," he says.