[Simplified, low-cost gene expression profiling for the prediction of outcome in breast cancer based on routine histologic specimens].

Grade 2 breast carcinomas do not form a uniform prognostic group. To extend the number of patients and the investigated genes of a previously identified prognostic signature described by the authors that reflect chromosomal instability in order to refine characterization of grade 2 breast cancers and identify driver genes. Using publicly available databases, the authors selected 9 target and 3 housekeeping genes that are capable to divide grade 2 breast carcinomas into prognostic groups. Gene expression was investigated by polymerase chain reaction in 249 formalin-fixed, paraffin-embedded breast tumors. The results were correlated with relapse-free survival. Histologically grade 2 carcinomas were split into good and a poor prognosis groups. Centroid-based ranking showed that 3 genes, FOXM1, TOP2A and CLDN4 were able to separate the good and poor prognostic groups of grade 2 breast carcinomas. Using appropriately selected control genes, a limited set of genes is able to split prognostic groups of breast carcinomas independently from their grade.