The inflammatory microenvironment of tumors is characterized by the presence of host leukocytes both in the supporting stroma and in tumor areas. [16] Tumor-infiltrating lymphocytes may contribute to cancer growth and spread and to the immunosuppression associated with malignant disease. Sometimes, cancer-causing chronic inflammation stems from a disease characterized by inflammation. The inflammatory diseases colitis, pancreatitis and hepatitis, for example, are linked to a greater risk of colon, pancreatic and liver cancers, respectively. An inflammatory process starts when chemicals are released by the damaged tissue. Over time, chronic inflammation can cause DNA damage and lead to cancer. For example, people with chronic inflammatory bowel diseases, such as ulcerative colitis and Crohn disease, have an increased risk of colon cancer.