Illumina (NSDQ:ILMN) has delayed its proposed $8 billion acquisition of Grail amid a FTC challenge.

The companies have agreed to postpone the planned purchase until after Sept. 20 while the FTC challenges the deal, according to a temporary restraining order issued out of U.S. District Court in the District of Columbia.

News of Illumina’s agreement to delay the purchase of the cancer detection startup that spun out from the company four years ago follows the company’s announcement just days ago that it disagreed with and will oppose the FTC’s challenge to its acquisition of Grail.

San Diego-based Illumina called the FTC’s challenge to the proposed transaction “a marked departure from longstanding antitrust precedent.” The company said it planned to pursue all legal options to complete the acquisition.

FTC’s complaint alleges the proposed acquisition will diminish innovation for multi-cancer early detection tests, which could potentially detect up to 50 types of cancer and save millions of lives worldwide. Grail is one of several companies competing to develop liquid biopsy tests, which rely on DNA sequencing of blood or other bodily fluids.

“The vast majority of cancers, which account for about 80% of cancer deaths, are only detected after patients exhibit symptoms. That is often too late to treat effectively,” said Rebecca Kelly Slaughter, FTC’s acting chair. “The MCED test is a game-changer for cancer patients and their loved ones. If this acquisition is consummated, it would likely reduce innovation in this critical area of healthcare, diminish the quality of MCED tests, and make them more expensive.”