OBJECTIVETo evaluate the association between SLC22A1 expression and the outcomes of hepatocellular carcinoma (HCC) patients.

METHODSA tissue microarray of 303 HCC and matched adjacent noncancerous liver tissues (ANLTs) were constructed. The expression of SLC22A1 was tested by immunohistochemistry (IHC) and scored by two pathologists according to a 12-score scale (a score>6 was defined as high expression, and a score≤6 as low expression). The correlation of SLC22A1 expression with the clinicopathological features and the patients' outcome was analyzed.

RESULTSAll the ANLTs had a IHC score of 12, as compared to only 29 (9.6%) of the HCC tissues. The patients were divided into 2 groups based on the IHC scores: 59% (180/303) in low expression group and 41% (123/303) in high expression group. The disease-free survival (DFS) rates and overall survival (OS) rates were significantly lower in low SLC22A1 expression group than in the high expression group. The 1-, 3-, and 5-year DFS rates were 43%, 31% and 27% in the low expression group, and were 58%, 47% and 43% in the high expression group, respectively. The 1-, 3-, and 5-year OS rates were 66%, 38% and 32% in low expression group, and were 80%, 57% and 50% in the high expression group, respectively. A low expression of SLC22A1 was positively correlated with the tumor diameter, BCLC stage, tumor differentiation, and AFP levels (P<0.05), and was an independent predictor of poor overall survival (HR=1.454; 95% CI, 1.050-2.013).

CONCLUSIONSDown-regulation of SLC22A1 is a malignant feature and a potential prognostic marker of HCC.