AIM:To investigate the angiogenesis-related protein expression profile characterizing metastatic colorectal cancer (mCRC) with the aim of identifying prognostic markers.METHODS:The expression of 44 angiogenesissecreted factors was measured by a novel cytokine antibody array methodology.The study evaluated vascular endothelial growth factor (VEGF) and its soluble vascular endothelial growth factor receptor (sVEGFR)-1 protein levels by enzyme immunoassay (EIA) in a panel of 16 CRC cell lines.mRNA VEGF and VEGF-A isoforms were quantified by quantitative reverse-transcription polymerase chain reaction (Q-RT-PCR) and vascular endothelial growth factor receptor (VEGFR)-2 expression was analyzed by flow cytometry.RESULTS:Metastasis-derived CRC cell lines expressed a distinctive molecular profile as compared with those isolated from a primary tumor site.Metastatic CRC cell lines were characterized by higher expression of angiogenin-2 (Ang-2),macrophage chemoattractant proteins-3/4 (MCP-3/4),matrix metalloproteinase-1 (MMP-1),and the chemokines interferon γ inducible T cell α chemoattractant protein (I-TAC),monocyte chemoattractant protein I-309,and interleukins interleukin (IL)-2 and IL-1α,as compared to primary tumor cell lines.In contrast,primary CRC cell lines expressed higher levels of interferon γ (IFN-γ),insulin-like growth factor-1 (IGF-1),IL-6,leptin,epidermal growth factor (EGF),placental growth factor (PlGF),thrombopoietin,transforming growth factor β1 (TGF-β1) and VEGF-D,as compared with the metastatic cell lines.VEGF expression does not significantly differ according to the CRC cellular origin in normoxia.Severe hypoxia induced VEGF expression up-regulation but contrary to expectations,metastatic CRC cell lines did not respond as much as primary cell lines to the hypoxic stimulus.In CRC primary-derived cell lines,we observed a twofold increase in VEGF expression between normoxia and hypoxia as compared to metastatic cell lines.CRC cell lines express a similar pattern of VEGF isoforms (VEGF 121,VEGF 165 and VEGF 189) despite variability in VEGF expression,where the major transcript was VEGF 121.No relevant expression of VEGFR-2 was found in CRC cell lines,as compared to that of human umbilical vein endothelial cells and sVEGFR-1 expression did not depend on the CRC cellular origin.CONCLUSION:A distinct angiogenesis-related expression pattern characterizes metastatic CRC cell lines.Factors other than VEGF appear as prognostic markers and intervention targets in the metastatic CRC setting. AIM: To investigate the angiogenesis-related protein expression profile characterizing metastatic colorectal cancer (mCRC) with the aim of identifying prognostic markers. METHODS: The expression of 44 angiogenesis contributed factors was measured by a novel cytokine antibody array methodology. The study evaluated vascular endothelial growth factor (VEGF) and its soluble vascular endothelial growth factor receptor (sVEGFR) -1 protein levels by enzyme immunoassay (EIA) in a panel of 16 CRC cell lines. mRNA VEGF and VEGF-A isoforms were quantified by quantitative reverse-transcription polymerase chain reaction (Q-RT-PCR) and vascular endothelial growth factor receptor (VEGFR) -2 expression was analyzed by flow cytometry. RESULTS: Metastasis-derived CRC cell lines expressed a distinctive molecular profile as compared with those isolated from a primary tumor site. Metastatic CRC cell lines were characterized by higher expression of angiogenin-2 (Ang-2), macrophage chemoattractant proteins-3/4 (MCP-3/4) trix metalloproteinase-1 (MMP-1), and the chemokines interferon γ inducible T cell α chemoattractant protein (I-TAC), monocyte chemoattractant protein I-309, and interleukins interleukin (IL) -2 and IL-1α, as compared to Primary tumor cell lines. In contrast, primary CRC cell lines were expressed higher levels of interferon γ (IFN-γ), insulin-like growth factor-1 (IGF-1), IL-6, leptin, epidermal growth factor placental growth factor (PlGF), thrombopoietin, transforming growth factor β1 (TGF-β1) and VEGF-D, as compared with the metastatic cell lines. VEGF expression does not significantly differ according to the CRC cellular origin in normoxia. Severe hypoxia induced VEGF expression up-regulation but contrary to expectations, metastatic CRC cell lines did not respond as much as primary cell lines to the hypoxic stimulus. In CRC primary-derived cell lines, we observed a twofold increase in VEGF expression between normoxia and hypoxia as compared to metastatic cell lines. CRC cell lines express a sim ilar paThe VEGF / VEGF isoforms (VEGF 121, VEGF 165 and VEGF 189) have variability in VEGF expression, where the major transcript was VEGF 121. The relevant expression of VEGFR-2 was found in CRC cell lines, as compared to that of human umbilical vein endothelial cells and sVEGFR-1 expression did not depend on the CRC cellular origin. CONCLUSION: A distinct angiogenesis-related expression pattern characterizes metastatic CRC cell lines. Factors other than VEGF appear as prognostic markers and intervention targets in the metastatic CRC setting.