Overexpression and clinical significance of carcinoembryonic antigen-related cell adhesion molecule 6 in colorectal cancer.

ABSTRACT

BACKGROUND: 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. METHODS: 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. RESULTS: 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 (p<0.001). High expression levels of CEACAM6 were significantly associated with lower overall survival (p<0.001) and shorter recurrence-free survival (p<0.001). 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. CONCLUSIONS: 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.