Expression of mucin (MUC) genes in mucoepidermoid carcinoma.

OBJECTIVES/HYPOTHESIS: Mucoepidermoid carcinoma (MEC) is the most common malignant salivary gland tumor. The presence of mucin (MUC) genes has been correlated with patient prognosis using immunohistochemical techniques. This study was undertaken to 1) investigate the expression of newly discovered MUC genes in MEC specimens, 2) assess the correlation of this expression to prognosis, and 3) further investigate the correlation of previously identified MUC genes to prognosis using molecular techniques.

STUDY DESIGN

Retrospective chart review and sample isolation.

METHODS

Twenty-three patients with a diagnosis of MEC underwent mucin gene analysis of tumor and normal surrounding salivary gland tissue. Initial expression analysis of recently identified mucin genes MUC 12, 13, 17, 18, and 19 was performed using reverse transcription-polymerase chain reaction (RT-PCR) followed by quantitative assessment with quantitative PCR. Additional assessments of mucin genes MUC 1 and MUC 4, which have previously been associated with MEC, were also analyzed with real-time RT-PCR.

RESULTS

MEC was associated with MUC 19 expression in 65% of tumor samples compared to only 26% of normal tissue (P = .02). MUC 18 demonstrated equal expression in both tumor and normal tissue. MUC 12 and 17 were not expressed in either MEC or normal salivary gland. MUC 13 was found in 13% of tumors and 0% of normal samples. MUC 1 and MUC 4 were expressed 4.2- and 21-fold higher in stage I disease in tumor tissue compared to normal, respectively.

CONCLUSIONS

Presence of MUC 19 is suggestive of mucoepidermoid carcinoma, and higher expression of MUC 1 and MUC 4 is correlated with earlier stage disease.