(NewsNation) — Researchers at the University of Pennsylvania have turned a deadly fungus into a potent cancer-fighting compound after isolating a new class of molecules from it.

Aspergillus flavus is a toxic crop fungus that has been linked to deaths in the excavation of ancient tombs. It was recently used in a test against leukemia cells and resulted in those cells being killed.

“Fungi gave us penicillin,” said Dr. Sherry Gao, senior author of the study. “These results show that many more medicines derived from natural products remain to be found.”

The aspergillus flavus, named for its yellow spores, has been known as a microbial villain for years.

A series of deaths following the excavation of King Tutankhamun’s tomb in 1922 started fueling rumors of a “pharaoh’s curse.” The discovery of King Casimir IV’s tomb in Poland in 1973 led to the deaths of 10 scientists who entered it. The investigations of both tombs revealed they contained the deadly fungus.

Researchers say the next step is to test those compounds in animals with the hope of one day moving to human clinical trials.