Background: Growing evidence suggests that the members of the ubiquitin-proteasome system (UPS) areimportant for tumorigenesis. HERC4, one component, is a recently identified ubiqutin ligase. However, theexpression level and function role of HERC4 in lung cancer remain unknown. Our objective was to investigateany correlation between HERC4 and development of lung cancer and its clinical significance. Materials and
Methods: To determine HERC4 expression in lung cancer, an immunohistochemistry analysis of a tissuemicroarray containing samples of 10 lung normal tissues, 15 pulmonary neuroendocrine carcinomas, 45 squamousepithelial cancers and 50 adenocarcinomas was conducted. Receiver operating characteristic (ROC) curveanalysis was applied to obtain a cut-off point of 52.5%, above which the expression of HERC4 was regardedas “positive”.
Results: On the basis of ROC curve analysis, positive expression of HERC4 was detected in 0/10(0.0%) of lung normal tissues, in 4/15 (26.7%) of pulmonary neuroendocrine carcinomas, in 13/45 (28.9%) ofsquamous epithelial cancers and in 19/50 (38.0%) of adenocarcinomas. It showed that lung tumors expressedmore HERC4 protein than adjacent normal tissues (χ2=4.675, p=0.031). Furthermore, HERC4 positive expressionhad positive correlation with pT status (χ2=44.894, p=0.000), pN status (χ2=43.628, p=0.000), histological grade(χ2=7.083, p=0.029) and clinical stage (χ2=72.484, p=0.000), but not age (χ2=0.910, p=0.340).
Conclusions: Ouranalysis suggested that HERC4 is likely to be a diagnostic biomarker for lung cancer.