Positron emission tomography scans like this one show the locations of metastatic tumors. WIKIMEDIA, AKRIA KOUCHIYAMAAlthough metastasis is the leading cause of death among people with cancer, researchers are stumped about which molecular signals trigger the exit of malignant cells from primary tumors to start new ones in other parts of the body. Two studies published in Nature this month highlight roles in metastasis for an unexpected group of molecules—lipids.
“For many years, we were studying peptides and proteins,” said Mariusz Ratajczak, a cell biologist at the University of Louisville who was not involved in the studies. “Now we are coming to bioactive lipids.”
In the first study, published January 5, researchers at the Institute for Research in Biomedicine (IRB) in Barcelona reported that, in mice, human oral cancer cells that are most likely to migrate from primary tumors are marked by the surface protein, CD36—a scavenger receptor that binds fatty acids. The researchers initially identified the cells by examining genes upregulated in nondividing tumor cells, finding increased expression of genes involved in lipid metabolism, transport, and storage—all processes downstream of CD36.
When the researchers knocked down CD36 with short hairpin RNA before the injecting ...
