Role of CRTC1/MAML2 Translocation in the Prognosis and Clinical Outcomes of Mucoepidermoid Carcinoma.

IMPORTANCE: The CRTC1/MAML2 fusion transcript, which arises from the CRTC1/MAML2 translocation, is a molecular marker unique to mucoepidermoid carcinoma (MEC), the most common malignant tumor of the salivary gland. The extent to which the transcript influences disease features and patient survival is unclear.

OBJECTIVE: To determine whether the CRTC1/MAML2 fusion transcript is associated with disease stage, tumor grade, or survival outcomes in patients with MEC.

DESIGN, SETTING, AND PARTICIPANTS: A retrospective medical record review was performed at a tertiary-care academic medical institution. The review included 90 patients with MEC who underwent treatment from January 1, 1995, to December 31, 2011, and for whom archived formalin-fixed, paraffin-embedded tumor specimens were available. Records were reviewed for clinical, demographic, and survival data. Tumor specimens underwent fluorescence in situ hybridization. Follow-up was completed on May 15, 2014, and data were analyzed from June 1 to July 1, 2014.

MAIN OUTCOMES AND MEASURES: CRTC1/MAML2 fusion transcript status. Statistical analysis determined whether transcript status was associated with disease stage, tumor grade, and/or overall and disease-free survival.

RESULTS: Among the 90 eligible patients (median [range] age, 55.1 [7.8-89.2] years), 42 were female and 48 were male. Fluorescence in situ hybridization revealed a CRTC1/MAML2 translocation in 50 patients (56%). The translocations were more prevalent in intermediate-grade tumors (31 of 49 [63%]) than in high-grade (11 of 49 [22%]) and low-grade (7 of 49 [14%]) tumors; 1 tumor sample had no available grading. Similar proportions of patients with translocation-positive disease had T1 (13 of 49 [26%]), T2 (15 of 49 [31%]), T4a (14 of 49 [28%]), or T0 or Tx (8 of 49 [16%]) stages of disease. Thirty-eight of 49 patients with translocation-positive MEC (78%) had N0 stage of disease. Rates of 5-year overall survival were similar for patients with translocation-positive and translocation-negative disease (76.8% vs 75.5%, respectively; P = .17), as were rates of disease-free survival (65.2% vs 57.4%, respectively; P = .28).

CONCLUSIONS AND RELEVANCE: Detection of the CRTC1/MAML2 fusion transcript provides useful information for MEC diagnosis but is not associated with differences in survival outcomes.