Gene expression signatures in breast cancer distinguish phenotype charact., histological subtypes, and tumor invasivness. Homo sapiens

Background. The development of reliable gene expression profiling technology is having an increasing impact on our understanding of breast cancer biology. Methods. In this study, microarray analysis was performed in order to establish gene signatures for different breast cancer phenotypes, determine differentially expressed gene sequences at different stages of the disease, and identify sequences with biological significance for tumor progression. Samples were taken from patients before their treatment. After microarray analysis, the expression level of 153 selected genes was studied by qPCR. Results. A number of gene sequences were differentially expressed in tumor versus control samples and were also associated with different breast cancer phenotypes, ER status, tumor histology, and grade of tumor differentiation. In N0 tumors were found a set of genes related to tumor differentiation grade. Conclusion. A number of differentially expressed gene sequences were found at different stages of the breast cancer disease. Key Words: Breast cancer, gene expression signature, tumor invasiveness, microarrays, qPCR Overall design: In total, 58 samples were studied, 31 tumors and 27 controls. Some of the samples are paired