Why some patients develop metastases and others do not is largely unclear. Researchers around ISTA professor Daria Siekhaus are now contributing to a better understanding of the process in certain types of cancer. They took a close look at the role of a protein called MFSD1—the mammalian relative of a protein they had previously identified as affecting cell migration in fruit flies. Therefore, first author Marko Roblek from the Siekhaus group created mouse cancer cells lacking the protein. Without the protein, cells traveled much faster, suggesting that MFSD1 prevents the cells from moving. Together with collaborators from the University of Zurich, the team tested their theory in living mice with breast, colon, and skin cancer. “In the absence of MFSD1, there was a strong increase in metastasis,” Daria Siekhaus summarizes the results.