LA JOLLA—Normally when we think of viruses, from the common cold to HIV, we want to boost people’s immunity to fight them. But for scientists who develop therapeutic viruses (to, for example, target cancer cells or correct gene deficiencies) a more important question is: How do we keep people’s natural immune responses at bay? In…

LA JOLLA—Just as an invasive weed might need nutrient-rich soil and water to grow, many cancers rely on the right surroundings in the body to thrive. A tumor’s microenvironment—the nearby tissues, immune cells, blood vessels and extracellular matrix—has long been known to play a role in the tumor’s growth.