Identification of Novel Tumor Suppressor Genes for Breast Cancer

摘要

Chromosomal deletions are very common events in breast cancer. However, no TSGs have been identified from most of recurrent deletions and few identified TSGs do not account for the risk of majority of breast cancer. In additional to the classical TSGs, there are haplo-insufficient TSGs which defy the identification through mutation analysis and may be quite common. By using a new system to generate random chromosomal deletions, we identified a 3Mbp deletion in mouse chromosome 3, which was associated with tumorigenesis. The expression of Fat4 in the deleted region was inactivated due to promoter methylation in the second allele of Fat4, and the re-expression of Fat4 suppressed the tumorigenecity, suggesting Fat4 as a strong candidate for breast tumor suppressor genes. We also found that Fat4 expression was lost in a high proportion of human breast cancers, some of which were attributed to Fat4 promoter methylation.