Amid the remarkable race to develop coronavirus tests, vaccines and treatments, many investors might overlook another realm of ­impressive medical breakthroughs. ­Molecular diagnostic firms are developing innovative blood tests that can detect many forms of cancer, some even at the earliest stages before cancerous cells mass together. The blood tests, which look for DNA fragments shed by cancerous cells, can provide information about cell mutations driving the cancer. That allows doctors to select the most effective treatment for each individual patient. 

In the past five years, genomic blood testing has become a $6 billion-a-year market, mostly driven by tests such as “liquid biopsies” that allow patients with potentially cancerous tumors to avoid expensive and invasive surgery to remove sample tissue…and tests that monitor for cancer recurrence in patients who already have had treatments. Over the next decade, the diagnostics market is expected to soar to more than $50 billion annually as companies ­develop early-detection tests to screen asymptomatic patients for cancers. 

Three promising companies…

Exact Sciences (EXAS) had nearly $900 million in total revenues last year, mostly from two products—Cologuard, an alternative to colonoscopies that screens stool samples for colon cancer, and Oncotype Dx, a genomic test that can predict which women with early-stage breast cancer will not benefit from chemotherapy. 

Guardant Health (GH) makes liquid biopsy kits that test for mutations in the tumors of advanced cancer patients to enable proper therapy selection. 

Natera (NTRA) tests monitor for relapses in breast and lung cancer and can identify recurrent tumors months before traditional methods such as CT scans. The company also is expanding its blood-test technology to predict whether organ-transplant recipients are likely to reject a new organ.