ObjectiveTo measure the expression of NOB1 in liver cancer tissues, and to investigate the relationship between NOB1 and clinicopathological features of liver cancer. MethodsA total of 48 liver cancer samples were collected from the patients who underwent liver cancer surgery in our hospital from February 2011 to May 2015, and 22 samples of cirrhotic liver tissues and 22 samples of normal liver tissues were collected as controls. The immunohistochemical SP method was used to measure the expression of NOB1 in different tissues, and the relationship between the expression of NOB1 and clinicopathological features was analyzed. The chi-square test was applied for comparison of categorical data between groups. ResultsThe expression of NOB1 in liver cancer tissues was significantly higher than that in cirrhotic liver tissues and normal liver tissues (72.9% vs 36.4%/31.8%; P=0.004 and 0.001), while the expression of NOB1 showed no significant difference between cirrhotic liver tissues and normal liver tissues (P＞0.05). The patients with a tumor diameter of ＞5 cm had a significantly higher positive rate of NOB1 than those with a tumor diameter of ≤5 cm (χ2=4.355, P=0.037), and the patients with Edmondson grade Ⅲ/Ⅳ tumor had a significantly higher positive rate of NOB1 than those with Edmondson grade Ⅰ/Ⅱ tumor (χ2=5.127, P=0.024). The expression of NOB1 in liver cancer tissues was not correlated with age, sex, presence or absence of microvascular invasion, presence or absence of lymph node metastasis, and clinical TNM stage (all P＞0.05). ConclusionNOB1 is highly expressed in liver cancer tissues. The expression of NOB1 is closely related to tumor size and Edmondson grade, and can be used as an important tumor marker for liver cancer.