CRTC1/3-MAML2 Fusions Are Not Seen in Metaplastic Warthin Tumors and Metaplastic Pleomorphic Adenomas of Salivary Glands
Alena Skalova, Tomas Vanecek, Lukas Hauer, Michal Michal. Charles University, Faculty of Medicine, Pilsen, Czech Republic; Bioptic Laboratory, Pilsen, Czech Republic
Background: The recurrent translocations t(11;19) and t(11;15) resulting in CRTC1-MAML2 or CRTC3-MAML2 fusion oncogenes, respectively, are identified in a large proportion of mucoepidermoid carcinomas (MEC) of the salivary gland and have impact on prognosis. However, there are conflicting data on specificity of this translocation, in particular, on its ocurrence in Warthin tumor (WT) of the parotid gland. It was speculated that extensive squamous metaplasia in WT could explain the presence of t(11;19) translocation in a subset of WTs.
Design: We have evaluated 15 cases of metaplastic WT and 8 cases of pleomorphic adenomas (PA) with squamous and/or mucinous metaplasia, extensive enough to mimic MEC. Detections of CRTC1-MAML2 and CRTC3-MAML2 fusion transcripts were performed using nested RT-PCR. 20 cases of low-grade fusion positive MEC were included for comparison.
Results: None of 15 analyzed metaplastic WT showed positivity for fusion transcripts CRTC1-MAML2 or CRTC3-MAML2. We did not detect above mentioned transcripts in any case of PA with extensive squamous/mucinous metaplasia, as well. All 20 cases of low grade MEC revealed CRTC1-MAML2 translocation, however, CRTC3-MAML2 translocation was not detected in any case.
Conclusions: We present our experience with the CRTC1-MAML2 and CRTC3-MAML2 translocations in a cohort of salivary gland tumors with extensive squamous and mucinous metaplasia. In contrast to low grade MEC, nor metaplastic pleomorphic adenomas neither metaplastic Warthin tumor harbored translocations t(11;19) and t(11;15).
Category: Head & Neck
Monday, March 4, 2013 2:00 PM
Proffered Papers: Section F, Monday Afternoon