Cipriani NA, et al. - Researchers examined mucoepidermoid carcinoma (MEC) grading systems and MAML2 rearrangement status for their prognostic significance in MEC. According to modified Healey, Brandwein, AFIP, and Katabi systems, they graded 53 carcinomas originally diagnosed as MEC (45 primary; 8 recurrent) of major and minor salivary glands. For MAML2 rearrangement, they performed fluorescence in situ hybridization. In all grading systems, 25 (47%) carcinomas scored the same. Isolated solid growth was identified to be the most common histologic feature leading to a diagnosis of intermediate grade. The highest percentage was assigned by Brandwein to high grade (29%) and the highest percentage was assigned by AFIP to low grade (80%). MAML2 rearrangement was recorded in 37/46 (80%) cases. Non-MEC morphology, stage T4, and high Brandwein grade were identified to be the statistically significant univariate risk factors for recurrence. No predictive value of margin status, MAML2 rearrangement, and isolated solid growth was noted for recurrence. Biological behavior in MEC could be better assessed via a binary grading system (Brandwein high vs low-plus-intermediate). Outcomes affirm that MAML2 wildtype tumors more frequently represent high grade non-MECs; high-grade non-MECs may weaken the findings from prior studies demonstrating worse prognosis in MAML2-nonrearranged MECs.