Infrequent mutation of ATBF1 in human breast cancer.

Deletion at chromosome 16q is frequent in prostate and breast cancers, suggesting the existence of one or more tumor suppressor genes in 16q. Recently, the transcription factor ATBF1 at 16q22 was identified as a strong candidate tumor suppressor gene in prostate cancer, and loss of ATBF1 expression was associated with poorer prognosis in breast cancer. In the present study, we examined mutation, expression, and promoter methylation of ATBF1 in 32 breast cancer cell lines. Only 2 of the 32 cancer cell lines had mutations, although 18 nucleotide polymorphisms were detected. In addition, 24 of 32 (75%) cancer cell lines had reduced ATBF1 mRNA levels, yet promoter methylation was not involved in gene silencing. These findings suggest that ATBF1 plays a role in breast cancer through transcriptional downregulation rather than mutations.