Like many cancers, the exact causes of pancreatic cancer are unknown. Cancer cells are the result of mutations in the cells. These mutations make the cells grow and reproduce too quickly, causing them to build up in the tissues. When cancer cells form in your pancreas, a tumor may grow. This tumor can damage the pancreas and spread to other parts of the body. The stage of pancreatic cancer is based on the size of the tumor and where it has spread. Stage 2 indicates that the tumor has spread beyond the pancreas.