
The main causes of several malignant tumors are microorganisms - viruses or bacteria. Stomach cancer is one of them - its main cause is a bacterium living in the stomach - Helicobacter pylori. For the first time, potential recommendations related to Helicobacter pylori are being analysed, in the process of developing the European Anti-Cancer Code of Conduct. M. Leja also participates in the working group related to tumors caused by infection.