LAF-4 is aberrantly expressed in human breast cancer

✍ Scribed by Minh D. To; Stephanie A. Faseruk; Nalan Gokgoz; Dushanthi Pinnaduwage; Susan J. Done; Irene L. Andrulis

• Publisher: John Wiley and Sons
• Year: 2005
• Tongue: French
• Weight: 289 KB
• Volume: 115
• Category: Article
• ISSN: 0020-7136
• DOI: 10.1002/ijc.20881

✦ Synopsis

Abstract

LAF‐4, which encodes a nuclear protein with transactivation potential, is fused to the MLL gene in acute lymphoblastic leukemia (ALL). We identified LAF‐4 as a gene that is transcriptionally deregulated in breast tumors and thus may have a pathological role in mammary tumorigenesis. In line with the previous finding that LAF‐4 expression is tissue specific, we did not detect any LAF‐4 mRNA in normal mammary epithelial cell lines. However, 2 of 5 breast cancer cell lines were found to express LAF‐4 at both the RNA and protein levels. In 2 of 9 primary tumor‐normal pairs, the expression of LAF‐4 was clearly elevated in the tumor tissue. Using RNA in situ hybridization, we demonstrated that LAF‐4 is expressed in mammary tumor cells but not in normal acini. In a group of 64 primary human breast tumors, we found that LAF‐4 was overexpressed in approximately 20% of the cases. Although epigenetic changes may be involved in altered expression of some genes, differences in LAF‐4 expression were not associated with DNA methylation of the predicted promoter region. Our results suggest that LAF‐4 may be a proto‐oncogene that is transcriptionally activated in some cases of breast cancer. © 2005 Wiley‐Liss, Inc.