Background: Cell proliferation and migration are the determinants of malignant tumor progression, and a better understanding of related genes will lead to the identification of new targets aimed at preventing the spread of cancer. Some studies have shown that KIAA1199 (CEMIP) is a transmembrane protein expressed in many types of noncancerous cells and cancer cells. However, the potential role of KIAA1199 in the progression of cholangiocarcinoma (CCA) remains unclear.

Results: Analysis of cancer-related databases showed that KIAA1199 is overexpressed in CCA. ELISA, immunohistochemistry, Western blotting and qPCR indicated high expression levels of KIAA1199 in serum, CCA tissues and CCA cell lines. In the serum (n = 41) and large sample validation (n = 177) cohorts, higher KIAA1199 expression was associated with shorter overall survival and disease-free survival times. At the cellular level, KIAA1199 overexpression (OE) promoted CCA growth and metastasis. Subcutaneous tumor xenograft experiments showed that KIAA1199 enhances CCA cell proliferation. Additionally, the expression levels of components in the EMT-related TGF-β pathway changed significantly after KIAA1199 upregulation and silencing.

Conclusion: KIAA1199 is a promising new diagnostic molecule and therapeutic target in CCA. The serum KIAA1199 level can be used as a promising clinical tool for predicting the overall postoperative outcomes of patients with CCA.

Methods: CCA-related KIAA1199 data were downloaded from the Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA) databases. To assess the prognostic impact of KIAA1199, an enzyme-linked immunosorbent assay (ELISA) was used to measure the serum level of KIAA1199 in 41 patients who underwent surgical resection. Immunohistochemical staining, Western blotting and qPCR were used to verify and retrospectively review the expression levels of KIAA1199 in cancer tissue specimens from 177 CCA patients. The effect of KIAA1199 on CCA was evaluated by cell-based functional assays and subcutaneous tumor xenograft experiments. The expression levels of proteins associated with epithelial-mesenchymal transition (EMT) and activation of relevant signaling pathways were measured via Western blotting.