Clinicopathological significance of MAML2 gene split in mucoepidermoid carcinoma. Issue 1 (8th November 2012)

• Record Type: Journal Article
• Authors: Noda, Haruna; Okumura, Yoshihide; Nakayama, Takahisa; Miyabe, Satoru; Fujiyoshi, Yukio; Hattori, Hideo; Shimozato, Kazuo; Inagaki, Hiroshi
• Is Part Of: Cancer science. Volume 104:Issue 1(2013:Jan.)
• Page Start: 85
• Page End: 92
• Publication Date: 2012-11-08
• Subjects: Cancer -- Periodicals; Neoplasms -- Periodicals; Research -- Periodicals; Electronic journals; 616.994005
• DOI: 10.1111/cas.12039
• Languages: English
• ISSNs: 1347-9032

Abstract

<abstract abstract-type="main" id="cas12039-abs-0001"> <title> <x xml:space="preserve">Abstract</x> </title> <p> <italic>CRTC1</italic>–<italic>MAML2</italic> and <italic>CRTC3–MAML2</italic> fusions have been associated with favorable clinicopathological features of mucoepidermoid carcinomas. However, the significance of the <italic>MAML2</italic> gene split has not been fully clarified. In the present study, 95 mucoepidermoid carcinomas (paraffin‐embedded materials) were analyzed for <italic>CRTC1–MAML2</italic> and <italic>CRTC3–MAML2</italic> fusions by RT‐PCR and for the <italic>MAML2</italic> gene split by FISH. Quantitative RT‐PCR for the <italic>CRTC1–MAML2</italic> transcript was performed in selected cases. <italic>MLL</italic> gene involvement, which has been reported in some leukemia cases, was examined by FISH in fusion partner‐unknown cases. <italic>CRTC1–MAML2</italic> and <italic>CRTC3–MAML2</italic> fusions were detected in 37 and 6 cases, respectively. The <italic>MAML</italic>2 gene split was detected in 62 cases, which included all <italic>CRTC1/3–MAML2</italic> fusion‐positive cases. The level of <italic>CRTC1–MAML2</italic> transcript expression was highly variable, and its clinicopathological impact was unclear. The <italic>MLL</italic> gene split was not detected. Mucoepidermoid carcinomas negative for <italic>CRTC1/3–MAML2</italic> and positive for the <italic>MAML2</italic> gene split (<italic>n </italic>=<italic> </italic>19) showed favorable clinicopathological tumor features similar to those positive for <italic>CRTC1/3–MAML2</italic> fusions. Compared with negative cases (<italic>n </italic>=<italic> </italic>33), mucoepidermoid carcinomas positive for the <italic>MAML2</italic> split (<italic>n </italic>=<italic> </italic>62) were associated with lower patient age, a mild female predilection, a smaller tumor size, less frequent nodal metastasis, a lower clinical stage, a lower histological grade, and longer overall and disease‐free survival. The <italic>MAML2</italic> gene split emerged as an independent prognostic factor for both overall and disease‐free survival in multivariate prognostic analysis. The presence of the <italic>MAML2</italic> gene split defines a distinct mucoepidermoid carcinoma subset that is associated clinicopathologically with favorable tumor features. (<italic>Cancer Sci</italic> 2013; 104: 85–92)</p> </abstract>