Impact of CRTC1/3-MAML2 fusions on histological classification and prognosis of mucoepidermoid carcinoma

Okumura Y, Miyabe S, Nakayama T, Fujiyoshi Y, Hattori H, Shimozato K & Inagaki H (2011) Histopathology59, 90–97 Impact of CRTC1/3–MAML2 fusions on histological classification and prognosis of mucoepidermoid carcinoma Aims: The aim of study was to evaluate the impact of CRTC1–MAML2 and CRTC3–MAML2 fusions on the histological classification of mucoepidermoid carcinoma (MEC) of the salivary glands and on the prognosis of patients. Methods and results: MEC cases (n = 111) were screened for CRTC1–MAML2 and CRTC3–MAML2 fusions by reverse transcription polymerase chain reaction. We developed a system of ‘molecular Armed Forces Institute of Pathology (AFIP) classification’ that combined the AFIP histological classification proposed by Goode et al. and the presence of CRTC1–MAML2 or CRTC3–MAML2 fusions. MEC cases positive for CRTC1–MAML2 or CRTC3–MAML2 fusion formed a favourable tumour subset that was distinct from fusion‐negative cases. When positive for the fusions, ‘high‐risk’ patients, including those with a higher histological grade or an advanced clinical stage, showed an excellent prognosis. For overall survival, ‘molecular AFIP classification’ was selected as a powerful independent prognostic factor (P = 0.0038), as was the clinical stage (P = 0.0032). For disease‐free survival, ‘molecular AFIP classification’ was also selected as an independent prognostic factor (P = 0.0006). Conclusions: Molecular AFIP classification may be useful in predicting the prognosis of patients with MEC.