ECRG4 is a promising tumor suppressor gene (TSG) recently identified in esophageal carcinoma. Its expression and prognostic value have never been explored in breast cancer. Using DNA microarray, we examined ECRG4 mRNA expression in 353 invasive breast cancer samples. A meta-analysis was performed on a large public retrospective gene expression dataset (n=1,387) to analyze correlation between ECRG4 expression and histo-clinical features including survival.
Overall design
To determine ECRG4 mRNA expression in breast cancer and normal breast, we first analyzed gene expression data generated by our laboratory (Institut Paoli Calmettes (IPC), Marseille, France) from cancer and normal mammary samples. Tumor tissues were from 353 patients with invasive adenocarcinoma who underwent initial surgery at IPC between 1987 and 2007. The study was approved by our institutional review board. Each patient gave a written informed consent for research use. Samples were macrodissected and frozen in liquid nitrogen within 30 min of surgical removal. All profiled specimens contained more than 60% of cancer cells (as assessed before RNA extraction using frozen sections adjacent to the profiled samples). After surgery, patients received an adjuvant multimodal treatment according to standard guidelines. Extraction of nucleic acids from frozen samples was done by using guanidium isothiocynanate and cesium chloride gradient. Expression profiles had been established for these 353 cancers pools with Affymetrix U133 Plus 2.0 human microarrays (Affymetrix®, Santa Clara, CA, USA).
Less...
More...