Why some cancers are worse than others

Megan Sweet slices tumors. A normal day in the lab finds the Virginia Tech graduate student with hands deep inside a refrigerated metal box, pulling a mounted mouse-grown tumor incrementally closer to a razor-sharp blade. "It's all about fine tuning and making sure it's going to be an even slice," said Sweet, who studies biological sciences. Finally, the blade meets the pinkie nail-sized nub of tissue and slices through it with a rhythmic chunk, chunk, chunk, chunk. "This is the hardest and most time-consuming part," Sweet said. "But it's also kind of meditative."