Human Pancreas Tumor Organoids (IMAGE) Cold Spring Harbor Laboratory Caption Researchers discovered that pancreas cancer subtypes can switch between a slow-growing type and another more invasive and deadly form. This image shows human pancreas tumor "organoids" (five large circular structures). The organoids contain many cells that overexpress K-Ras (in red), a notorious driver of many cancers. Cells that express more K-ras behave more dangerously, dividing more frequently and invading surrounding tissues. Note the dense mats of blue stained cell nuclei, indicating that the cells are dividing quickly. Green stains F-actin, which shows the shapes of cells. Credit Miyabayashi/Tuveson lab, CSHL Usage Restrictions Attribution required License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.