AIM:To analyze the relevance of the microRNA miR196a for colorectal oncogenesis. METHODS:

In different tumour entities, expression of the chemokine receptor 4 (CXCR4) has been linked to tumour dissemination and poor prognosis. Therefore, we evaluated, if the expression of CXCR4 exerts similar effects in human hepatocellular carcinoma (HCC). Expression analysis and functional assays were performed in vitro to elucidate the impact of CXCL12 on human hepatoma cells lines. In addition, expression of CXCR4 was evaluated in 39 patients with HCC semiquantitatively and correlated with both, tumour and patients characteristics. Human HCC and hepatoma cell lines displayed variable intensities of CXCR4 expression. Loss of p53 function did not impact on CXCR4 expression. Exposure to CXCL12 mediated a perinuclear translocation of CXCR4 in Huh7/ Hep3B cells and increased the invasive potential of Huh7 cells. In HCC patients, CXCR4 expression significantly correlated with progressed local tumours (T-status; P ¼ 0.006), lymphatic metastasis (N-status; P ¼ 0.005) and distant dissemination (M-status; P ¼ 0.009), as well as with a decreased 3-year-survival rate (P ¼ 0.01). In summary, strong expression of CXCR4 is significantly associated with progressed hepatocellular cancer.

Background: Prognosis of esophageal cancer is poor despite curative surgery. The chemokine receptor CXCR4 has been proposed to distinctly contribute to tumor growth, dissemination and local immune escape in a limited number of malignancies. The aim of our study was to evaluate the role of CXCR4 in tumor spread of esophageal cancer with a differentiated view of the two predominant histologic types -squamous cell and adenocarcinoma.

As new multi-target tyrosine kinase inhibitors are emerging in the therapy of various malignancies, our aim was to define the co-expression pattern of receptor-tyrosinekinase platelet-derived growth factor receptors α and ß (PDGFRα/ß) in human colorectal cancer. The co-expression pattern of PDGFRα/ß was analyzed by RT-PCR in 99 histologically confirmed human colorectal carcinomas and five colorectal cancer cell lines. In addition, immunohistochemical (IHC) staining was applied for confirmation of expression and analysis of receptor tyrosine kinase (RTK) localisation. The colorectal cancer cell lines that were analysed revealed varying expression intensities of PDGFRα and PDGFRß. The majority of human colorectal cancer specimens revealed a PDGFRα (83%) or PDGFRß (60%) expression. While PDGFRα showed a predominantly cytoplasmic staining in tumor cells as well as in stromal pericytes, PDGFRß was restricted to stromal pericytes only. Furthermore, PDGFRα expression significantly correlated with lymph node metastasis (P=0.0082) and advanced UICC stages III/IV (P=0.018) in older patients (P=0.043). PDGFRß expression only revealed a trend towards lymphatic dissemination (P=0.099). Co-expression of PDGFRα/ß occurred in 57% of the colorectal cancer samples, whereas another 29% of the samples depicted mono-expression of PDGFRα or PDGFRß. Notably, PDGFRα/ß expression significantly correlated with lymphatic metastasis (P=0.007) and advanced UICC stages III/IV (P=0.017) in older patients (P=0.03). In summary, our results revealed that PDGFRα/ß expression significantly correlates with lymphatic dissemination and therefore encourages application of PDGFRα/ß RTK-inhibitors within a combination therapy.

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This study aimed to define the co-expression pattern of target receptor tyrosine kinases (RTKs) in human esophageal adenocarcinoma and squamous cell cancer. The co-expression pattern of vascular endothelial growth factor receptor (VEGFR)1-3, platelet-derived growth factor receptor (PDGFR)α/ß and epidermal growth factor receptor 1 (EGFR1) was analyzed by RT-PCR in 50 human esophageal cancers (35 adenocarcinomas and 15 squamous cell cancers). In addition, IHC staining was applied for the confirmation of the expression and analysis of RTK localisation. The adenocarcinoma samples revealed VEGFR1 (97%), VEGFR2 (94%), VEGFR3 (77%), PDGFRα (91%), PDGFRß (85%) and EGFR1 (97%) expression at different intensities. Ninety-four percent of the esophageal adenocarcinomas expressed at least four out of six RTKs. Similarly, squamous cell cancers revealed VEGFR1 (100%), VEGFR2 (100%), VEGFR3 (53%), PDGFRα (100%), PDGFRß (87%) and EGFR1 (100%) expression at different intensities. All esophageal squamous cell carcinomas expressed at least four out of six RTKs. While VEGFR1-3 and PDGFRα and EGFR1 was expressed by tumor cells, PDGFRß was restricted to stromal cells, which also depicted a PDGFRα expression. Our results revealed a high rate of RTK co-expression in esophageal adenocarcinoma and squamous cell cancer and may encourage application of multi-target RTK inhibitors within a multimodal concept as a promising novel approach for innovative treatment strategies.

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