Infections - Infections and Cancer Epidemiology Group
The most recent, conservative estimates attribute 18% of cancers worldwide to infectious agents. Among the most important players are human papillomavirus (HPV, 5%, nearly 10% among women), hepatitis B and C viruses (HBV and HCV, 5%) and Helicobacter pylori (6%).
Cancer-associated infections represent a very good opportunity to study the relationship between inflammation and cancer for several reasons: (1) chronic inflammation of the target organs is one of the main mechanisms through which some of the aforementioned infections induce the development of pre-neoplastic and neoplastic lesions (e.g. HCV, Helicobacter pylori); (2) when cancer-associated viruses are known to induce cancer through direct mechanisms at the cell genome level (e.g. HPV), co-infection with other bacteria (e,g., Chlamydia trachomatis) or viruses (e.g. herpes simplex virus type 2) has been shown to further increase the risk of cancer (e.g. cervical cancer). A special case is represented by agents such as the human immunodeficiency virus (HIV), whose main mechanism of cancer induction is impairment of the immune system and, hence, enhancement of the probability of a wide spectrum of infections, including cancer-associated ones.