Immunohistochemical Analysis of the Ubiquitin-Conjugating Enzyme UbcH10 in Lung Cancer: A Useful Tool for Diagnosis and Therapy

The ubiquitin-conjugating enzyme (UbcH10) plays important roles in the regulation of cell cycle progression. Recently, UbcH10 expression has been demonstrated in several human and experimental tumors and proteasome inhibitors have been tested in trials for pulmonary neoplasms; however the underlying mechanisms as well as the clinicopathological relevance of UbcH10 in the genesis and progression of lung cancer remain largely unknown. Therefore, we evaluated the expression of UbcH10 in human lung cancer and evaluated its possible diagnostic and prognostic use. We found that the majority of cases of lung adenocarcinoma, squamous cell carcinoma, large cell and small cell carcinoma were positive for UbcH10. The expression levels of UbcH10 progressively increased with decreasing degree of tumor differentiation. There was a statistically significant difference of UbcH10 positivity between grade I/III of lung adenocarcinoma (P= 0.013) and squamous cell carcinoma (P= 0.002). No significant differences were found between histological types (P= 0.072). In the case of cell blocks prepared from pleural effusions, inflammatory and reactive mesothelial elements did not show appreciable UbcH10 expression while neoplastic cells exhibited clear UbcH10 positivity. Our results suggest that UbcH10 might represent a new and promising diagnostic and prognostic marker in both histologic and cytologic specimens of lung cancer.