Novel high-throughput analyses in molecular biology allow sensitive and rapid identification of disease-related genes and drug targets. We have used quantitative real-time reverse transcription-PCR reactions (n ‫؍‬ 23,000) to analyze expression of all human receptor tyrosine kinases (n ‫؍‬ 56) in malignant tumors (n ‫؍‬ 313) of different origins and normal control samples (n ‫؍‬ 58). The different tumor types expressed very different numbers of receptor tyrosine kinases: whereas brain tumors and testicular cancer expressed 50 receptor tyrosine kinases, acute myeloid leukemia (AML) samples expressed only 20 different ones. Specimens of similar tumor origin exhibited characteristic receptor tyrosine kinase expression patterns and were grouped together in hierarchical cluster analyses. When we focused on specific tumor entities, receptor tyrosine kinases were identified that were disease and/or stage specific. Leukemic blasts from AML bone marrow samples differed significantly in receptor tyrosine kinase expression compared with normal bone marrow and purified CD34؉ cells. Among the differentially expressed receptor tyrosine kinases, we found FLT3, c-kit, CSF1 receptor, EPHB6, leukocyte tyrosine kinase, and ptk7 to be highly overexpressed in AML samples. Whereas expression changes of some of these were associated with altered differentiation patterns (e.g., CSF1 receptor), others, such as FLT3, were genuinely overexpressed in leukemic blasts. These data and the associated database (http://medweb.uni-muenster.de/institute/meda/research/) provide a comprehensive view of receptor tyrosine kinase expression in human cancer. This information can assist in the definition of novel drug targets.

Low-dose antiproliferative sulindac therapy is highly effective in adenoma reversion in familial adenomatous polyposis patients. Sulindac shows influence on tumor-suppressor genes and on apoptosis markers. An immunostaining correlation indicates adenoma relapse in flat microadenomas in advance of macroscopic appearance. Low-dose sulindac treatment may develop into an additive permnanent therapy for colectomized familial adenomatous polyposis patients.

The aim of this study was to analyze the occurrence of TOP2A gene amplification and chromosome 17 polysomy in patients with early breast cancer and to correlate the status of these alterations with the prognostic significance expressed as patients' clinical features and survival. Such concurrent analyses of TOP2A gene status and chromosome 17 polysomy have not been performed before. Study group included 149 consecutive stage I-III patients administered standard multimodality treatment. TOP2A abnormalities were examined by standard fluorescence in situ hybridization (FISH) and developed by our group quantitative real-time PCR (qPCR). TOP2A amplification and deletion assessed by FISH were found in 23% and 7% of the tumours, respectively, and by qPCR in 31% and 11% of the tumours, respectively. Chromosome 17 polysomy was detected in 40% of the cases. TOP2A amplification (by qPCR) correlated with shorter disease-free survival (p = 0.03) and overall survival (p = 0.047), and the prognostic value of TOP2A was confirmed in the multivariate analysis (HR = 3.22, 95% CI 1.09-9.56, p = 0.03). TOP2A gene amplification, but not chromosome 17 polysomy, carries negative prognostic information in early breast cancer. Given the aforementioned results, qPCR might serve as a prognostic tool in determining the patient's prognosis.

Background: Risk estimation based on the recommendations of St. Gallen Consensus commonly decides for additional cytostatic therapy in node-negative (N-), hormone receptor positive (HR+) primary breast cancer patients. High proliferative activity in the HR+ subtype confers a 19-fold relative risk of relapse compared with HR+ tumors of low proliferative activity. Furthermore immunohistochemically determined Ki-67 is characterized as a Luminal B marker that identifies a high risk subgroup in HR+, N- breast cancer patients.Aim of this investigation was to compare risk estimation using Ki-67 (%) with the results of a RT-PCR based multi-gene prognostic signature. Methods: Tumor tissues of totally 321 unselected primary breast cancer patients were formalin fixed and routinely processed for immunohistochemical determination and scored for protein expression of ER, PgR and Ki-67. HER2 was determined using dd-PCR. Content of both hormone receptors and proliferation activity were evaluated counting positively coloured nuclei from at least 100 tumor cells. The median follow up was 61 months. To calculate the cut off for high proliferation Ki-67 values were subjected to a log rank CART analysis. High proliferation was defined by Ki-67 of 19% and more. With this cut off it was possible to distinguish significantly various patient cohorts (N-, pT1, postmenopausal) into two different risk groups regarding metastasis free survival. The definition of low risk was low proliferation and HER2 negativity, of high risk high proliferation or HER2 positivity. The risk for metastasis of 16 new primary breast cancer patients was estimated based on two surrogate risk groups and the multi-gene prognostic signature. Results: Tamoxifen adjuvant treated HR+, HER2-, low proliferating (Ki-67 <19%), N- low risk patients (N= 68) and HR+, HER2-, high proliferating/HR+, HER2+, N- high risk patients (N= 84) showed a recurrence rate of 2.94% and 27.4%, respectively (P< .000). In the ongoing observation study all 5 low proliferating HER2- tumors had a low risk gene prognostic signature. From 11 high proliferating HER2- patients one patient had a low risk gene signature (9%), 3 patients a moderate risk gene signature (27%) and 7 patients a high risk gene signature (64%). Conclusion: Despite the small number of patients investigated up to now (N= 16) the preliminary results appear to show that low proliferative activity is associated with a low risk gene prognostic signature, whereas high proliferation means only in part a high risk gene prognostic signature. Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 6025.

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