Beta-Secretase 1 (BACE1) Is Down-Regulated in Invasive Ductal Carcinoma of Breast

Background: The enzyme beta-secretase 1 (BACE1) and its antisense transcript (BACE1-AS) have been implicated in the pathogenesis of Alzheimer's disease. Moreover, several lines of evidence point to their contribution in tumorigenesis. Methods: In the present study, we evaluated expression of BACE1 mRNA (BACE1) and BACE1-AS in 54 breast cancer tissues and 54 adjacent non-cancerous tissues (ANCTs) from the same patients using quantitative real-time PCR. Results: BACE1 was significantly down-regulated in tumoral tissues compared with ANCTs, while BACE1-AS expression was not significantly different between tumoral tissues and ANCTs. The Bayesian Multilevel model showed a significant difference in BACE1 expression between stage 1 and 2 cancers after age-effect adjustments. BACE1-AS expression was significantly greater in ER-positive than in ER-negative samples (P=0.01). BACE1 and BACE1-AS expression were not correlated with patient ages in any sample sets. Conclusions: Significant correlations were detected between expression of these genes in both tumoral tissues and ANCTs. The current study provides evidence for differential BACE1 expression in breast tissues and suggests further assessment of the role of BACE1 in the pathogenesis of cancer.