Expression of amphiregulin in mucoepidermoid carcinoma of the major salivary glands: a molecular and clinicopathological study.

In mucoepidermoid carcinoma (MEC), CRTC1-MAML2 fusion indicates a favorable prognosis. Amphiregulin (AREG), an epidermal growth factor receptor (EGFR) ligand, has been shown to be a downstream target of CRTC1-MAML2 fusion, and to play a role in tumor growth and survival in CRTC1-MAML2-positive MEC cell lines. The aim of this study was to characterize the AREG and EGFR expression in the fusion-positive and fusion-negative MEC of the major salivary gland. The AREG and EGFR expression were studied by immunochemistry in 33 MEC cases of the major salivary glands. CRTC1-MAML2 fusion was tested by reverse-transcription polymerase chain reaction (23 CRTC1-MAML2 fusion-positive, 10 fusion-negative). Of 23 fusion-positive cases, AREG and EGFR overexpression were detected in 17 (73.9%) and 14 (60.9%) cases, respectively. Of 10 fusion-negative cases, AREG and EGFR overexpression were detected in 1 (10%) and 3 (30.0%) cases, respectively. There was a positive correlation between CRTC1-MAML2 fusion and AREG overexpression (P < .01), but not between CRTC1-MAML2 fusion and EGFR overexpression. The AREG overexpression was associated with a longer disease-free survival of the MEC patients (P = .042), but EGFR overexpression was not. In this study, we showed that AREG overexpression was detected more frequently in the CRTC1-MAML2 fusion-positive tumors than in fusion-negative tumors. Detection of AREG expression may be useful for identifying CRTC1-MAML2-positive MECs and as a marker for favorable prognosis.