Becoming invasive is a crucial step in breast cancer oncogenesis. At this point, a lesion carries the potential for spreading and metastasis -a process, whose molecular characteristics still remain poorly understood. In this article, we describe a matched-pair analysis of ductal carcinoma in situ (DCIS) and invasive ductal carcinoma (IDC) of nine breast ductal carcinomas to identify novel molecular markers characterizing the transition from DCIS to IDC. The purpose of this study was to better understand the molecular biology of this transition and to identify candidate genes whose products might serve as prognostic markers and/or as molecular targets for treatment. To obtain cellular-based gene expression profiles from epithelial tumor cells, we combined laser capture microdissection with a T7-based two-round RNA amplification and Affymetrix oligonucleotide microarray analysis. Altogether, a set of 24 tumor samples was analyzed, comprised of nine matched DCIS/IDC and replicate DCIS/IDC preparations from three of the nine tumors. Cluster analysis on expression data shows the robustness and reproducibility of the techniques we established. Using multiple statistical methods, 546 significantly differentially expressed probe sets were identified. Eighteen candidate genes were evaluated by RT-PCR. Examples of genes already known to be associated with breast cancer invasion are BPAG1, LRRC15, MMP11, and PLAU. The expression of BPAG1, DACT1, GREM1, MEF2C, SART2, and TNFAIP6 was localized to epithelial tumor cells by in situ hybridization and/or immunohistochemistry, confirming the accuracy of laser capture microdissection sampling and microarray analysis. (Cancer Res 2006; 66(10): 5278-86)

International audienceNumerous studies have shown that the presence of clinically occult disseminated tumor cells (DTC's) in the bone marrow (BM) of breast cancer patients is associated with an unfavourable clinical outcome. Immunocytochemistry (ICC) remains the gold standard for their detection. While assays based on RT-PCR are available, they have not been used for routine detection of DTC's. To assess the quality of the assay, we performed a direct comparison of DTC detection rates in a large cohort of 385 patients using both standardized ICC and real-time RT-PCR protocols. Correlation rates were assessed, and results were compared with clinical data. A significant correlation between ICC and RT-PCR was observed ( < 0.01). Positivity rates were similar (both 35%) and the results of both methods agreed in 73% of cases (280/385). We describe a real-time RT-PCR based protocol for DTC-detection that has been specifically designed for routine clinical laboratory use. As such, RT-PCR has the potential to become an alternative testing method for BM evaluation in breast cancer patients

10619 Background: The concept of early breast cancer detection has evolved to mean the discovery of a premalignant lesion or an early stage invasive lesion prior to metastasis. Therefore, methods must be developed to identify the actual primogenitors of cancer, those lesions which with certainty will progress to cancer. Currently, two technologies are employed for routine imaging of the breast: mammography and ultrasonography. Neither of these techniques can unequivocally distinguish between benign and malignant tissue limiting them to detection but not diagnosis. We hypothesize that differences in Raman spectra will enable the accurate discrimination of breast lesions one from one another and from normal breast epithelia. Therefore, preliminary studies were performed to investigate the potential of Raman spectroscopy. Methods: Cyropreserved breast tissue was selected, sectioned (10 μM) and stained with Hematoxylin and Eosin to verify the histologic diagnosis and to guide the acquisition of Raman spectra from a consecutive section (30 μM). This “analysis” section is mounted on Permanox (polyolefin; Nunc, Rochester, NY) over an area of the slide perforated with small holes (dia. 1mm) to provide the laser with direct access to the tissue without background Raman scattering from the polyolefin. Using a Raman microscope spectra were obtained from multiple areas of five breast tumors to address the reproducibility of spectral similarities across different tumors, to identify spectral differences between malignant and benign tissue, to identify spectral differences between invasive and ductal carcinoma in situ (DCIS) and to optimize the integration time. Results: In general, the spectral profiles for each tissue type are conserved with distinct differences in the predominance and peak widths of specific vibrations. Even in the absence of complex algorithms, malignant vs. benign tissue identification is possible. An analysis of the ability to reliably distinguish between invasive ductal carcinoma and DCIS will have to await additional spectra. A sound vibrational fingerprint of the tissue, consistent with that of the high signal/noise scan at 10 minutes, can be obtained within 30 seconds. Conclusions: Raman spectroscopy with short collection times shows promise and warrants further investigation. No significant financial relationships to disclose.

Supplementary Data 1 from Progression-Specific Genes Identified by Expression Profiling of Matched Ductal Carcinomas <i>In situ</i> and Invasive Breast Tumors, Combining Laser Capture Microdissection and Oligonucleotide Microarray Analysis