Alpha-fetoprotein (AFP) is a common diagnostic marker for hepatocellular carcinoma (HCC) , a highly malignant cancer, but its sensitivity is only 41%-65%, and the rate of missed diagnosis is relatively high. Therefore, there is an urgent need to develop new diagnostic markers and methods to improve the detection rate of AFP-negative and other types of HCC.

To assess the diagnostic efficacy of muscarinic acetylcholine receptor m3 autoantibody (m3AchR-Ab) in AFP-negative HCC, and to explore the diagnostic value of m3AchR-Ab in HCC.

Participants (n=257) were selected from the First Affiliated Hospital of Xinjiang Medical University, including 90 with confirmed diagnosis of HCC, 89 with liver cirrhosis, hepatic hemangioma or other benign liver diseases, and 78 healthy controls. ELISA was the technique used for measuring the serum m3AchR-Ab level in venous blood samples of all cases stored in the serum repository of the hospital from November 2011 to September 2015. Serum m3AchR-Ab levels were compared in the three groups. The associations of serum m3AchR-Ab level with gender, age, size (the maximum diameter) of HCC, number and TNM stage of HCC, prevalence of lymph node metastasis, distant metastasis and HBsAg positivity in HCC patients were analyzed. The efficacy of m3AchR-Ab in the diagnosis of AFP-negative HCC was evaluated by the receiver operating characteristic (ROC) curve.

HCC patients had higher serum m3AchR-Ab level than benign liver disease patients and healthy controls (P<0.05) . The level of m3AchR-Ab was correlated with the size and TNM stage of HCC, as well as prevalence of lymph node metastasis and HBsAg positivity (P< 0.05) . The area under the ROC curve of serum m3AchR-Ab in the diagnosis of AFP-negative HCC was 0.69〔95%CI (0.54, 0.83) 〕, with 64.00% sensitivity and 91.02% specificity when 74.00 ng/ml was chosen as the optimal cut-off value. The area under the ROC curve of m3AchR-Ab with AFP in serum in diagnosing HCC was 0.90〔95%CI (0.85, 0.95) 〕, with 90.00% sensitivity and 88.02% specificity.

Serum m3AchR-Ab level is a potential diagnostic maker for AFP-negative HCC, and its combination with serum AFP level could produce higher diagnostic efficiency for HCC, which may be a reference for further research on novel diagnostic markers for HCC.

肝细胞癌（HCC）是一种恶性程度较高的癌症。甲胎蛋白（AFP）是临床常用的HCC诊断标志物，但其灵敏度仅为41%~65%，漏诊率较高，因此亟须寻找新的诊断标志物和诊断方法以提升AFP阴性患者等的HCC检出率。

评估毒蕈碱乙酰胆碱受体m3自身抗体（m3AchR-Ab）对AFP阴性HCC患者的诊断效能，并探索m3AchR-Ab对HCC患者的诊断价值。

选取2011年11月至2015年9月入库于新疆医科大学第一附属医院标本库的257例患者血清样本，其中90例已确诊为HCC患者的血清样本为HCC组，89例已确诊为良性肝病（肝硬化及肝血管瘤等肝病）患者的血清样本为良性肝病组，78例健康受试者的血清样本为对照组。使用酶联免疫吸附试验（ELISA）检测并比较3组血清m3AchR-Ab水平，分析血清m3AchR-Ab水平与HCC患者性别、年龄、HCC肿瘤大小（最大直径）和数量、TNM分期、淋巴结转移、远处转移、乙肝表面抗原（HBsAg）的关系，采用受试者工作特征（ROC）曲线评估血清m3AchR-Ab水平对AFP阴性HCC的诊断价值。

HCC组血清m3AchR-Ab水平高于良性肝病组和对照组血清（P<0.05）。m3AchR-Ab水平与HCC肿瘤大小、TNM分期、淋巴结转移和HBsAg相关（P<0.05）。血清m3AchR-Ab水平诊断AFP阴性HCC的ROC曲线下面积为0.69〔95%CI（0.54，0.83）〕，最佳截断值为74.00 ng/ml，灵敏度为64.00%，特异度为91.02%。血清m3AchR-Ab联合AFP水平诊断HCC的ROC曲线下面积为0.90〔95%CI（0.85，0.95）〕，灵敏度为90.00%，特异度为88.02%。

血清m3AchR-Ab水平对AFP阴性HCC具有一定的诊断价值，且使用m3AchR-Ab和AFP联合诊断可提高HCC诊断效能，这可为未来研究新型HCC诊断标志物提供更多参考。