High expression of SLC17A9 correlates with poor prognosis in colorectal cancer.

Solute carrier family 17 member 9 (SLC17A9) is a member of the family of transmembrane proteins that are involved in the transport of small molecules. The role of SLC17A9 in colorectal cancer (CRC) remains poorly understood. The present study aimed to demonstrate the clinicopathological significance and prognostic role of SLC17A9 in CRC. Here, we firstly analyzed the data from The Cancer Genome Atlas on SLC17A9 expression in CRC data sets and detected SLC17A9 expression level in 8 pairs of fresh CRC tissues and adjacent nontumorous tissues by quantitative real-time reverse-transcription polymerase chain reaction and Western blotting assays. Immunohistochemical staining was used to detect SLC17A9 protein expression in 144 CRC patients in our center. The bioinformatic analysis, Western blotting, and immunohistochemical analyses revealed that SLC17A9 was significantly up-regulated in CRC specimens compared with adjacent nontumorous tissues. SLC17A9 overexpression was significantly correlated with several clinicopathological features, such as advanced T stage (P < .001), N stage (P < .001), M stage (P < .001), TNM stage (P < .001), and tumor location (P = .01). A Kaplan-Meier survival curve suggested that higher SLC17A9 expression was statistically correlated with poor overall survival and disease-free survival in patients with CRC. Univariate and multivariate Cox regression analyses demonstrated that SLC17A9 was an independent prognostic predictor for survival of CRC patients. Therefore, our data suggested that SLC17A9 may play an important role in the progression of CRC and may potentially be used as an independent biomarker for prognostic evaluation of CRC.