Whole-genome-doubled cancer cells carry extra DNA, but their size may matter as much as their genetics. Virginia Tech researchers found that smaller tetraploid cells often grow more aggressively and, in some human cancers, are linked to poorer survival. Tumors do not all grow under the same rules, even when they share one of cancer’s most common genetic changes. At Virginia Tech, researchers studying cells with doubled genomes found that some of the most dangerous ones were not the biggest or most obviously distorted. They were smaller. That finding grew out of years of close work in the lab, where graduate student Megan Sweet slices mouse-grown tumors into thin, nearly translucent sections, stains them, and studies their structure under a microscope. Those repeated steps helped reveal a pattern that could sharpen how researchers think about cancer progression. The work, published in Cancer Research, focused on what happens after whole-genome doubling, an event in which a cell ends up with four complete sets of chromosomes instead of the usual two. Such cells are known as tetraploid cells, …