In colon cancer, CD133 has recently been used to enrich for a subset of tumour cells with tumour-initiating capabilities and was therefore suggested to mark colon cancer stem cells. However, this molecule has surprisingly been shown to lack functional importance for tumour initiation itself. Herein, we investigated whether CD133 may be relevant for colon cancer metastasis in patients, and as metastasis requires several additional biological characteristics besides tumour initiation, we examined the effects of knocking down CD133 expression in colon cancer cell lines on proliferation, migration, invasion, and colony formation. We demonstrate that high CD133 expression correlates strongly with synchronous liver metastasis in a matched case-control collection, while siRNA-mediated knock down of this factor has no significant effect on the mentioned biological characteristics. Thus, we conclude that CD133 expression is a marker with high prognostic impact for colon cancer, while it seems to have no obvious functional role as a driving force of this malignancy.

Background: The presence of mutated KRAS ( mut KRAS ctDNA) in plasma samples has been consistently shown to be a negative prognostic indicator in pancreatic cancer (PC). Only small pilot studies have evaluated the value of serial mut KRAS ctDNAmeasurements in PC. Patients and methods:The aim of the present study was to explore the potential of repeated mut KRAS ctDNA measurements for response prediction and therapy monitoring in advanced PC patients. We used the BEAMing technology to determine levels of mut KRAS ctDNA, CA 19-9, CEA and CYFRA 21-1 in 284 plasma samples of 54 patients with advanced PC receiving gemcitabinebased chemotherapy. Absolute levels and kinetics of mut KRAS ctDNA, CA 19-9, CEA and CYFRA 21-1 were correlated to radiological response, progression-free and overall survival.Results: mut KRAS ctDNA was present in a majority of advanced PC patients (n ¼ 36/54, 67%) and indicated tissue KRAS mutation status with a high sensitivity (75%) and specificity (100%). The presence of mut KRAS ctDNA, as well as higher levels of CA 19-9, CEA and CYFRA 21-1 before initiation of the first-line chemotherapy, was significantly correlated to an adverse overall survival. During therapy, changes in mut KRAS ctDNA levels were more rapid and pronounced than changes in protein-based tumor markers. A decrease in mut KRAS ctDNA levels during therapy was an early indicator of response to therapy, while there was no significant correlation between kinetics of CA 19-9, CEA or CYFRA 21-1 and response to chemotherapy during the first four weeks of treatment. Repeated mut KRAS ctDNA measurements during follow-up appeared to be superior to protein-based tumor markers in detecting progressive disease (sensitivity: 83%, specificity: 100%). Conclusion:mut KRAS ctDNA kinetics appear to be a powerful and highly specific tool in early response prediction and therapy monitoring of advanced PC patients receiving chemotherapy.

The proteomic approach is a valuable tool to detect and identify proteins that are associated with cancer. In previous investigations on experimentally induced rat hepatomas, we detected aldose reductase-like protein (ARLP) as a highly significant marker protein. Our present study was intended to look for the presence of similar tumor-associated marker proteins on human hepatocellular carcinomas (HCC). We found several novel tumorassociated protein variants that represent members of the aldo-keto reductase (AKR) superfamily. Human aldose reductase-like protein-1 (hARLP-1) was the most prominent tumorassociated AKR member detected in HCC by 2-dimensional electrophoresis (2-DE) and identified by mass spectrometric fingerprinting. The enzyme was found in 4 distinct forms H uman hepatocellular carcinoma (HCC) ranks fifth in worldwide cancer incidence and is an important component of public health. Many HCC risk factors are known, including hepatitis B or C (HBV or HCV) infection, ingestion of aflatoxin-contaminated food, and alcohol. 1,2 The development of HCC is associated with multiple changes at the messenger RNA (mRNA) and/or protein level, some of them serving as tumor markers, e.g., ␣-fetoprotein, 3 or, less specifically, cyclin D1 or the proliferating cell nuclear antigen. 4 Misprogramming of genetic information in cancer is reflected by quantitative and/or qualitative protein alterations. These protein alterations might represent tumor markers that are useful in the diagnosis of human tumors and may also help the understanding of mechanisms of tumor induction and development. Proteome analysis of liver proteins and HCC were predominantly performed using either chemically induced hepatomas in animals (predominantly the rat 5-10 ) or human HCC cell lines, such as HepG2 and Huh7 cells, 11 BEL-7404 cells, 12 or HCC-M cells. 2,13,14 Numerous so-called tumor-associated or cancer-related proteins were identified; these provide valuable information for the establishment of HCC protein databases. 2,[11][12][13][14] Comparative analysis of liver tissue and hepatocellular carcinomas might give additional insights into the induction or repression of tumor-associ-

Background: In the era of precision medicine, cancer treatment is increasingly tailored according to tumor-specific genomic alterations. The analysis of tumor-derived circulating nucleic acids in cerebrospinal fluid (CSF) by next generation sequencing (NGS) may facilitate precision medicine in the field of CNS cancer. We therefore evaluated whether NGS from CSF of neuro-oncologic patients reliably detects tumor-specific genomic alterations and whether this may help to guide the management of patients with CNS cancer in clinical practice.Patient and methods: CSF samples from 27 patients with various primary and secondary CNS malignancies were collected and evaluated by NGS using a targeted, amplicon-based NGS-panel (Oncomine Focus Assay). All cases were discussed within the framework of a molecular tumor board at the Comprehensive Cancer Center Munich.Results: NGS was technically successful in 23/27 patients (85%). Genomic alterations were detectable in 20/27 patients (74%), 11/27 (40%) of which were potentially actionable. After discussion in the MTB, a change of therapeutic management was recommended in 7/27 (26%) of the cases. However, due to rapid clinical progression, only 4/27 (15%) of the patients were treated according to the recommendation. In a subset of patients (6/27, 22%), a high number of mutations of unknown significance suggestive of a high tumor mutational burden (TMB) were detected.Conclusions: NGS from cerebrospinal fluid is feasible in routine clinical practice and yields therapeutically relevant alterations in a large subset of patients. Integration of this approach into a precision cancer medicine program might help to improve therapeutic options for patients with CNS cancer.

Tumor cells are stressed by unfavorable environmental conditions like hypoxia or starvation. Driven by the resulting cellular stress tumor cells undergo epithelial-mesenchymal transition. Additionally, cellular stress is accompanied by endoplasmic reticulum-stress which induces an unfolded protein response. It is unknown if epithelial-mesenchymal transition and endoplasmic reticulum-stress are occurring as independent parallel events or if an interrelationship exists between both of them. Here, we show that in colorectal cancer cells endoplasmic reticulum-stress depends on the induction of ZEB-1, which is a main factor of epithelial-mesenchymal transition. In the absence of ZEB-1 colorectal cancer cells cannot mount endoplasmic reticulum-stress as a reaction on cellular stress situations like hypoxia or starvation. Thus, our data suggest that there is a hierarchy in the development of cellular stress which starts with the presence of environmental stress that induces epithelial-mesenchymal transition which allows finally endoplasmic reticulum-stress. This finding highlights the central role of epithelial-mesenchymal transition during the process of tumorigenesis as epithelial-mesenchymal transition is also associated with chemoresistance and cancer stemness. Consequently, endoplasmic reticulum-stress might be a well suited target for chemotherapy of colorectal cancers.

This study emphasizes the advantage of combining suitable methods to ensure reproducibility and specific antigen detection. Based on our results, we propose a novel step-by-step strategy to validate antibody specificity and reduce variability of immunohistochemical results.

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The stable transfection of the canine CD34(-) multipotent cell line DO64 with retroviral constructs containing the cDNA for the canine major histocompatibility complex (MHC) class II DR genes led to the cell clone DO64#14, which is characterized by malignant transformation and tumor growth in nonobese diabetic/severe combined immunodeficient (NOD/SCID) mice. The additional expression of p27(kip-1) in the transformed cell clone partially reversed the malignant phenotype. Because several proteins associated with lipid rafts are involved in signal transduction and because changes of lipid raft composition are linked to the pathogenesis of leukemias, raft-associated proteins in DO64 cells and the deduced transformed cell clones were compared using a proteomic approach. Raft-associated proteins were separated by two-dimensional electrophoresis and identified by MALDI-TOF-MS. Here we show that the stem cell line DO64 and the deduced cell clones can clearly be distinguished by differences in the expression of a number of raft-associated proteins, namely caveolin-1, flotillin- 1, vimentin, galectin-3, and glyceraldehyde-3-phosphate dehydrogenase. All identified proteins play an important role in cellular functions and may therefore participate in raft-mediated leukemic transformation. Therefore, our study suggests that the analysis of lipid raft protein composition may be useful for the identification of molecular markers of the transformation process.