[Tumor suppressor genes: occurrence, significance and function].

Tumor-suppressor-genes were detected by DNA-analysis of childhood tumors. A homozygous deletion or mutation of these genes is closely associated with different malignant tumors. Tumor-suppressor-genes seem to play an important role in cellular development and differentiation. The understanding of this pathomechanism in cancerogenesis is most important for calculating a genetic risk for tumor development.