Cancer research in the weightlessness of space could help develop drugs targeting tumors that don't respond to current treatments, a U.S. journal reports. Research performed on the Chinese orbiting lab Shenzhou-8, launched in 2011, has shown some tumors seem to be much less aggressive in the microgravity environment of space compared to their behavior on Earth, researchers have reported in the Federation of the American Societies for Experimental Biology Journal. Such research offers unique insight into genetic and cellular processes that simply can't be duplicated on Earth, even in simulated microgravity, they said. "Microgravity can be approximated on Earth, but we know from the literature that simulated microgravity isn't the same as the real thing," said Daniela Gabriele Grimm, a researcher at Aarhus University Denmark and one of the authors of the FASEB paper. Cells grown in space arrange themselves into three-dimensional groupings that more closely resemble what happens in the body, he said. "Without gravitational pull, cells form three-dimensional aggregates, or spheroids," Grimm explained. "Spheroids from cancer cells share many similarities with metastases, the cancer cells which spread throughout the body." Determining the molecular mechanisms behind spheroid formation could help improve our understanding of how cancer spreads, she said.