Project description:RNA was isolated from FFPE tissue sections and expression profile of miRNAs determined by hybridization to Affymetrix GeneChip miRNA 4.0 Array Both normal and cancer samples were used. Normal cases included cosmetic reduction mammoplasties (the only true normal tissue) and tissues with some morphological abnormalities. Some benign, non-cancer, cases were also included. Breast cancer cases included invaive ductal and lobullar carcinomas as well as metaplastic breast cancer
Project description:Breast cancer and normal breast tissue samples to estimate the effect of contamination of breast cancer samples with normal breast tissue
Project description:PURPOSE: To estimate the effect of contamination with normal breast tissue for the development of gene signatures robust to pre-analytical conditions. METHODS: We evaluated the effect of contamination with normal breast tissue on gene signatures by comparing microarray profiles of breast cancer samples contaminated with increasing amounts of normal breast tissue.
Project description:MicroRNAs are a class of small non-coding RNAs that control gene expression by targeting messenger RNAs and triggering either translation repression or RNA degradation. Their aberrant expression may be involved in human diseases, including cancer. Indeed, microRNA aberrant expression has been previously found in human chronic lymphocytic leukemias, where microRNA signatures were associated with specific clinico-biological features. Here, we show that, in comparison to normal breast tissue, microRNAs are also aberrantly expressed in human breast cancer. The overall microRNA expression could clearly separate normal versus cancer tissues, with the most significantly deregulated microRNAs being mir-125b, mir-145, mir-21, mir-155. Results were confirmed by microarray and Northern blot analyses. We could identify microRNAs whose expression was correlated with specific breast cancer bio-pathologic features, such as estrogen and progesterone receptor expression, tumor stage, vascular invasion or proliferation index.