The diversity expression of p62 in digestive system cancers.

The expression of p62 autoantigen and the frequency of p62 autoantibody have been reported in hepatocellular carcinoma (HCC) and many types of malignant tumors, respectively, but information regarding to the expression of p62 in other cancer tissues and the association of autoantibody to p62 with tumor behaviors is not available. In the current study, the expression of p62 in tissues and the appearance of p62 autoantibody in sera were detected by immunohistochemical staining and ELISA in four clinical types of digestive system cancers including gastric cancer, esophageal cancer, large intestine cancer and HCC, respectively. Interestingly, the immunohistochemistry staining of p62 has been shown in all of digestive canal tissues (stomach, esophagus, large intestine) including tissues with cancers, beside cancers and from non-malignant patients, whereas the frequencies were 62.5% and 0% in tissues with cancer and beside cancer in patients with HCC, respectively. Importantly, we found that the p62 expression and the frequency of autoantibody to p62 were associated to cell differentiation and tumor metastasis, respectively. These results suggest that the expression of p62 in tissues and the appearance of autoantibody to p62 in sera might be related to cell malignant manifestations. Moreover, p62 autoantibody is a significant marker for the prognosis of cancers and the evaluation of clinical treatments.