AIM To investigate whether circulating cytokeratin-positive(CK~+) cells in the mesenteric blood of resected colorectal specimens are prognostic and correlate with tumor budding.METHODS Fifty-six colorectal specimens were collected between 9/2007 and 7/2008.Blood from the mesenteric vein was drawn immediately after receiving the fresh and unfixed specimens in the pathology department.After separation of the mononuclear cells by Ficoll-Hypaquedensity-gradient centrifugation,cytological smears were immunocytochemically stained for CK18.Tumor budding was evaluated on slides stained for pan-cytokeratin.The identification of ≥ 30 buds/1.3 mm2 was defined as high grade budding.RESULTS CK~+ cells and clusters were identified in 29(48%) and 14(25%) of the samples,respectively.Two cells were identified in one of three non-malignant cases.Clusters were found exclusively in malignant cases.The occurrence of CK~+ cells or clusters was not associated with any of the evaluated clinicopathological factors,including surgical technique and tumor budding.Moreover,the occurrence of CK~+ cells or clusters had no influence on the cancerspecific survival [75 mo(CI:61;88) vs 83 mo(CI:72;95) and 80 mo(CI:63;98) vs 79 mo(CI:69;89),respectively].CONCLUSION CK~+ cells and showed neither prognostic significance nor an association with tumor budding.It is very likely that CK18-staining is not specific enough to identify the relevant cells. AIM To investigate whether circulating cytokeratin-positive (CK ~ +) cells in the mesenteric blood of resected colorectal specimens are prognostic and correlate with tumor budding. METHODS Fifty-six colorectal specimens were collected between 9/2007 and 7/2008. Blood from the mesenteric vein was drawn immediately after receiving the fresh and unfixed specimens in the pathology department. After the separation of the mononuclear cells by Ficoll-Hypaquedensity-gradient centrifugation, cytological smears were immunocytochemically stained for CK18. Tumor budding was evaluated on slides stained for pan-cytokeratin The identification of ≥ 30 buds / 1.3 mm2 was defined as high grade budding .RESULTS CK ~ + cells and clusters were identified in 29 (48%) and 14 (25%) of the samples, respectively. Two cells were identified in one of three non-malignant cases. Clusters were found exclusively in malignant cases. the occurrence of CK ~ + cells or clusters was not associated with any of the the evaluated clinicopathological f actors, including surgical technique and tumor budding. More over the occurrence of CK ~ + cells or clusters had no influence on the cancerspecific survival [75 mo (CI: 61; 88) vs 83 mo (CI: 63; 98) vs 79 mo (CI: 69; 89), respectively] .CONCLUSION CK ~ + cells and showed neither prognostic significance nor an association with tumor budding. It is very likely that CK18-staining is not specific enough to identify the relevant cells.