Parasites Sebistosoma (Bilbarzia) could cause bladder cancer due to chronic irritation of the bladder. However, other chronic irritants do not cause cancer.
Infection by Clonorcbis, which is especially prevalent in the Far East, can cause cancer of the pancreas and bile ducts. Helicobacter pylori is a bacterium that may be the cause of gastric cancer. Presumably this bacterium causes gastric injury and chronic inflammation resulting in increased speed of the cell cycle.
Certain behaviors cause the likelihood of someone suffering from cancer. Such behavior such as smoking and eating foods that contain lots of fat and preserved meat. So also with the behavior associated with sexual behavior. Multiple sexual partners and sexual intercourse at an early age, increases the risk of human papilloma virus infection associated with genital neoplasms. Infection by herpes simplex virus type-2 are transmitted by sex relationships may increase the risk of cancer. Hepatitis B virus can be transmitted by sexual relationship and increase the risk of liver cancer.