The objective of oncogenetics, a medical discipline, is to:

• understand genetic predisposition to cancers
• care for persons at risk.

Genetic predispositions are often associated with a family history of cancer. However, cancers are very frequent and family histories exist, so a family history of cancer is not synonymous with a genetic predisposition.

The purpose of a genetic consultation is to determine the share of family history and possible predisposition.

Genetic tests, stills seldom practiced, sometimes confirm a hereditary origin. If an alteration is identified in a family, it can be sought in its relations. This makes it possible to reassure those having no predisposition and following up those at risk.