Expression of Ceramide Galactosyltransferase (UGT8) in Primary and Metastatic Lung Tissues of Non-Small-Cell Lung Cancer

Abstract

Ceramide galactosyltransferase (UGT8) is an enzyme that regulates the synthesis of sphingolipids of the myelin sheath in nervous systems. The protein raises an increasing research interest as a potential marker of cancer progression in various organs. In the present study we seek to determine whether UGT8 could play a role of a therapeutic marker in non-small cell lung carcinoma (NSCLC). We addressed the issue by examining the intensity of UGT8 expression in tissue specimens of primary and corresponding metastatic lung tumors in 19 NSCLC patients undergoing surgery. The methodology was one of immunohistochemical tissue staining using light microscopy. The findings were that the majority of both lung primary and metastatic tumor tissues were positive in UGT8 signals. The cytoplasmic expression of UGT8 was found in 68.4 % of cases of primary tumors and 82.2 % of metastases, with a positive correlation between the UGT8 expression in both tumor tissues. The normal tissue adjacent to tumors showed no positive UGT8 staining. However, we failed to find any appreciable difference in UGT8 expression depending on the clinical stage of NSCLC or lymph node involvement. Nor was there any association between UGT8 expression in tumor tissues and patients’ survival time. We conclude that it is unlikely that therapeutic targeting of UGT8 could inhibit cell proliferation and invasion of NSCLC. UGT8, although enhanced in NSCLC tissues, does not meet the criteria of a lung tumor marker. Thus, UGT8 cannot be considered as having diagnostic or therapeutic utility in NSCLC. The pathophysiological meaning of enhanced expression of UGT8 in lung cancer remains to be explored in further studies.