Three years ago Kevin Conroy was standing on Ireland’s Cliffs of Moher, gazing at the Atlantic Ocean 500 feet below, when he was blindsided by a phone call about his company’s colon cancer test.

Since 2009 Conroy has been running Exact Sciences, a firm trying to sell a noninvasive would-be alternative to a colonoscopy. The caller informed him that the influential U.S. Preventive Services Task Force had declined to recommend the Exact test as a cancer-screening tool, which meant it would not be covered by health plans under the Affordable Care Act. “Our stock took a massive hit,” says Conroy, 52. “It was surprising. In many ways energizing, though.”

Energized, Conroy sent in more data. In 2016 the task force gave the Exact test a green light. Exact’s share price is now more than triple what it was before the task force brush-off.

There are three main ways to detect colon cancer. A colonoscopy is accurate but expensive ($2,200 on average). A fecal immunochemical test, which looks for hidden blood in a stool sample, costs about $60 but is more likely to miss cancer and must be taken every year. Then there is Exact’s Cologuard for $649.

Like the immunochemical test, Cologuard uses a stool sample collected by the patient and checks for hemoglobin. It also looks for an assortment of aberrant DNA sequences that are likely to occur in cancerous and precancerous cells. Result: high enough sensitivity that patients can take the test only once every three years. Read the full story here.