Summary Cancer diseases are mostly sporadic, but it is estimated that about 5-10% may be of hereditary origin. Dozens of common or rare syndromes with a high risk of certain types of cancer exist.
In some of them the accumulation of cancer in a family is the only sign of hereditary predisposition. In this article the list of hereditary cancer syndromes is provided and the importance of genetic counselling and testing in oncology is explained.