Infectious Agents and Cancer

RESUMO

The epidemiology of several types of cancers indicate the involvement of several transmissible agents in their development; and in most cases; these seem to be viruses. The classic examplesare Burkitt's lymphoma; nasopharyngeal carcinoma (EBV); hepatocellular carcinoma (HBV); and cervical carcinoma (HPV). Most of these cancers show substantial variations in their incidencein different parts of the world and in particular countries; they present significant health problems. Worldwide; infections account for up to 20of all cancers. Also; there is now ample evidence implicating infection with the Helicobacter pylori in the occurrence of gastric carcinoma and gastric lymphoma; and infection with Schistosoma haematobium in the occurrence of the squamous cell carcinoma of the urinary bladder.The impact of these infections on the burden of cancer worldwide is becoming increasingly evident because they are largely responsible for the cascade of opportunistic malignancies associated with AIDS. The burden is heaviest among populations in developing countries; reflecting the impact of very early infection with these agents on subsequent risk of cancer. There are currently no vaccines available to prevent these chronic infections; other than for HBV. As a result; changes in behaviour hold the most promise for prevention