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Carcinoembryonic antigen-related cell adhesion molecule 6 (CEACAM6) inhibits anoikis and affects the malignant phenotype of cancer cells. In this study, we analyzed CEACAM6 as a gene that is highly upregulated in colon cancer tissues, and examined the assertion that CEACAM6 might be a suitable candidate tumor marker for the diagnosis of colon cancer.CEACAM6 gene expression in human colon tissues was performed by tissue microarray and analyzed using RT-PCR (each of normal and tumor tissue, n=40) and immunohistochemical and clinicopathological (colon cancer patients, n=143) analyses.CEACAM6 transcriptional and translational levels were significantly upregulated in human tumor tissues compared to non-tumor regions, and clinicopathological analysis revealed a significant correlation between CEACAM6 protein expression and Dukes' stage (p0.001). High expression levels of CEACAM6 were significantly associated with lower overall survival (p0.001) and shorter recurrence-free survival (p0.001). We demonstrated that knockdown of CEACAM6 with CEACAM6-specific small interfering RNA in colorectal cancer cells attenuated invasivity (35%); conversely, the overexpression of CEACAM6 increased invasiveness.CEACAM6 is significantly upregulated in colon cancer tissues and is closely associated with poor prognosis, indicating that CEACAM6 might be used as a tumor biomarker and a potential therapeutic target for colon cancer.

Background Macrophage inhibitory cytokine-1 (MIC-1), a distant member of the transforming growth factor (TGF)-β superfamily, has been reported to be upregulated and secreted from several cancers. We examined MIC-1 expression and secretion in gastric cancers. Methods MIC-1 mRNA and protein levels in cancer tissues and cell lines were analyzed by RT-PCR and Western blot. MIC-1 expression in cancer tissues and its secretion in serum were analyzed using immunohistochemistry and ELISA. Results MIC-1 was significantly upregulated in gastric cancer tissues and cell lines. MIC-1 was secreted from gastric SNU620 cells and its levels in the serum of cancer patients were 10-fold higher than those of healthy controls. In addition, the staining of MIC-1 expression was strongly increased in metastatic gastric cancers. Conclusions MIC-1 was obviously overexpressed in gastric cancers and MIC-1 secretion into blood may be useful for the prediction of gastric cancer progression.

Background N-myc downstream regulated gene 2 (NDRG2) belongs to the NDRG family, which is comprised of 4 members, NDRG1–4. Recently, NDRG2 was reported as a new candidate for a tumor suppressor gene. We developed a reverse-phase protein microarray assay to access NDRG2 levels in human tissue specimens and cell lines. Methods We synthesized recombinant NDRG2 protein and produced monoclonal antibodies (mAb) to the NDRG2 protein. We selected 2 hybridomas producing mAb that specifically recognize the NDRG2 protein. To determine the NDRG2 concentration, the samples of serially-diluted NDRG2 protein, cell lysate, or tissue lysate were spotted onto a nitrocellulose membrane-coated slide glass and allowed to react with the mAb to the NDRG2 protein. The reaction was followed by additional incubation with biotin-linked anti-mouse IgG and horseradish peroxidase (HRP)-conjugated streptavidin, subsequently. The addition of dimethylaminobenzidine induced color development, which was measured using the GenePix program. We determined the NDRG2 concentration in various tissue specimens and cell lines using the new protein microarray technique. Results The dose–response relationship between NDRG2 and color intensity showed linearity in a range 0–10 ng/ml and a sensitivity of 50 pg/ml. The NDRG2 concentrations in the liver tissue lysates of patients with hepatocellular carcinoma (52.0 + 21.5 ng/mg) were significantly diminished as compared with those in the normal liver tissues (549.6 + 94.6 ng/mg). The results of the assay showed good agreement with those of Western blot analysis. Conclusions The protein microarray is a highly sensitive and accurate method, and can adopted to assess specific proteins in human tissues or cell lines, particularly in the field of cancer and pathological research.

Background Serum asialoglycoproteins concentration are increased in patients with hepatic disease. We developed an antibody–lectin sandwich assay that is sensitive and specific to measure asialo-α1-acid glycoprotein (AsAGP) concentration in human serum and evaluated it as a biochemical marker for hepatic disease. Methods Serum AsAGP concentration was measured by antibody–lectin sandwich assay with 610 serum specimens of patients with hepatic disease. Serum from 41 healthy donors and 155 patients with non-hepatic disease served as negative controls. The AsAGP values were analyzed by receiver operator characteristics (ROC) curve analysis. The diagnostic accuracy of AsAGP value was compared with those of the conventional biochemical markers in the liver function test. Results Serum AsAGP concentration in 83% of patients with liver cirrhosis (LC) and 89% of patients with hepatocellular carcinoma (HCC) was increased over the cutoff value (1.33 μg/ml), indicating that an increase of serum AsAGP concentration is restricted to LC or HCC cases. The area under curve (AUC) in the ROC curve was 0.919 for LC and 0.946 for HCC. Conclusions Serum AsAGP concentration exhibited good diagnostic accuracy as a biochemical marker for LC and HCC. The addition of AsAGP to conventional liver function tests may significantly improve the diagnosis and prognosis.