Chen D, et al. – In order to find out whether down–regulation of the tumour suppressor κ–opioid receptor predicted poor prognosis in hepatocellular carcinoma patients, experts conducted this study. An association was observed between down–regulation of κ–opioid receptor (KOR) in hepatocellular carcinoma (HCC) tumour tissues and poor prognosis. Moreover, KOR seemed to be a potential tumour suppressor.