 Natural killer, NK, cells are important components of the immune system and play a key role in fighting cancer. In this study, researchers found that when exposed to lipopolysaccharide, LPS, NK cells migrate from the lymph node to the tumor site, where they can slow or stop tumor growth. This migration occurs even though NK cells do not appear to be actively recruited to the tumor site immediately following exposure to LPS. Instead, it appears that NK cells already present in the lymph node are activated and then migrate to the tumor site. Researchers also discovered that NK cell activation requires close contact with dendritic cells, DCS. These findings suggest that NK cells may be able to be used as a therapeutic tool to target tumors. This article was authored by Francesca Mingossi, Roberto Spriafico, Tatiana Galletta, and others.