Testudo, or tortoise formation, was one of the major tactical advantages enjoyed by ancient Roman armies and researchers at the University of Montreal's Institute for Research in Immunology and Cancer (IRIC) believe that some cells, including cancer cells, mimic the formation to some extent to move together in our body. Collective cell migration is an essential part of our body's growth and defense system, but it is also used by cancerous cells to disseminate efficiently in the body. "We have found a key mechanism that allows cells to coordinate their movement as a group and we believe that this mechanism is used by malignant cells in a number of cancers, including some types of breast, prostate and skin cancers" explained lead researcher Gregory Emery. Roman soldiers formed the tortoise, or testudo formation, by coming closely together and aligning their shields side-by-side in order to defend themselves as they broke their enemy lines. "As for the Romans, if some cancerous cells are migrating efficiently, it is because their movements are tightly coordinated. To stop their progression, we have first to understand how they coordinate. Then, we will aim at blocking this coordination in cancer cells to abrogate cancer progression."