On the other hand, the immune system can also CAUSE cancer

Infection with human papilloma virus (HPV) is the primary cause of cervical cancer and a subset of head and neck cancers worldwide. A University of Colorado Cancer Center paper describes a fascinating mechanism that links these two conditions – viral infection and cancer. The link, basically, is a family of enzymes called APOBEC3. These APOBEC3 enzymes are an essential piece of the immune system’s response to viral infection, attacking viral DNA to cause disabling mutations. Unfortun