Several members of the Ets (E26 transformation specific) transcription factor family are involved in tumor progression, e.g. by activating matrix metalloproteases. Ets proteins share a unique DNA-binding domain, the Ets domain, which specifically recognizes GGAA/T-containing sequences common in many promoters. While the roles of quite a number of Ets proteins in carcinogenesis have been well established, little is known about the importance of the Ets protein Elf-1 (E74-like factor 1) in cancer. Herein, we analyzed the expression of Elf-1 in breast cancer. We found that, like T-cells, breast cancer cells express both the 80 and 98 kDa isoforms of the Elf-1 protein with the 98 kDa isoform only be present in the nucleus. Immunohistochemical analysis of 119 breast cancer biopsies showed anti-Elf-1 immunoreactivity exclusively in the nucleus. Elf-1 expression varied largely among the breast cancer samples showing a negative correlation with histological grading. However, no association of Elf-1 expression with clinical outcome was observed, even when sub-cohorts of patients who received either only adjuvant endocrine treatment or only chemotherapy were separately analyzed. These data suggest that Elf-1 may modulate breast cancer progression to some extent without having an impact on survival of breast cancer patients.

Related Articles