Title: Progression-specific markers in breast cancer obtained by microarray analysis are located to the malignant epithelial tumor cells
Abstract: 834 Hematogenic metastasis is the major cause of mortality from malignant tumors. The potential of human breast tumor cells to metastasize is enabled after DCIS (ductal carcinoma in situ) to IDC (invasive ductal carcinoma) transition, when the cells become invasive and break through the basement membrane. It is imperative to gain more information about the molecular events accompanying this crucial step to improve the classification in risk groups for DCIS patients according to risk of relapse or progression and to advance in individualizing the therapy for DCIS and IDC patients. Our group combined Affymetrix microarray analysis with laser capture microdissection (LCM) to analyze matched DCIS and IDC tissue from nine patients. Subsequent to extensive statistical analysis (rank product, paired t-test, paired Mann-Whitney test), 446 up-regulated and 102 down-regulated Affymetrix probe sets were identified to be expressed differentially in either stage of the nine tumours (p-value: 0.01), characterizing the transition from DCIS to IDC. This gene list contains genes, already associated with breast cancer invasion (PLAU/uPa and MMP11) confirming the accuracy of the accomplished methods. Differential gene expression of 18 candidate genes (15 up-regulated, 3 down-regulated) was confirmed, analyzing triplicate real-time PCR experiments. Four PCR-validated candidates were selected for in situ hybridization experiments and the proteins of five PCR-validated candidates were detected using immunohistochemistry. These experiments confirm the localization of the transcripts or proteins for all tested candidates to the cytoplasm of the epithelial tumor cells. Regarding the immunohistochemical evaluation, differential gene expression corresponding to the microarray data could be visualized. In conclusion, we identified progression-specific candidate genes using an accurate stringent approach combining LCM and high-density oligonucleotide microarray analysis. New candidates, not yet correlated with breast cancer progression, could be validated using real-time PCR. Expression of candidate transcripts and proteins was localized to the epithelial tumor cells, respectively. Among these candidates are transmembrane receptors, transcription factors and tumour antigens, thus gene products with potential clinical importance.
Publication Year: 2006
Publication Date: 2006-04-15
Language: en
Type: article
Access and Citation
AI Researcher Chatbot
Get quick answers to your questions about the article from our AI researcher chatbot