Oncomine meta-analysis of breast cancer microarray data identifies upregulation of NRF-1 expression in human breast carcinoma

We have conducted a study where Oncomine microarray data was meta-analyzed to evaluate NRF-1 gene expression in human breast tumors. Our initial analyses indicated that NRF-1 gene is differentially expressed in breast cancer patients based on their estrogen receptor (ER) status. Therefore, in our first meta-analyses 18 studies were grouped separately for ER+ and ER-patients. It was observed that NRF-1 gene expression is up-regulated in ER + patients compared to ER-patients. Further, two separate meta-analyses on ER+ and ER-patients were conducted to associate NRF-1 gene expression levels for prognosis and for histological grades of breast tumors. In a combined 15 microarray studies, ER-patients with down regulated NRF-1 expression either died or had a relapse of cancer after the treatment. ER+ patients with increased levels of NRF-1 expression however, survived or had no relapse after treatment. Interestingly, in our third set of meta-analyses conducted on 15 studies, it was observed that NRF-1 gene expression also increased significantly with the progression of tumor grades from 1 to 3. Findings of this study have a major implication for the role of NRF-1 in the breast cancer, suggesting that NRF-1 possibly participates in the growth of breast cancer by altering its activity.