HER2 and EGFR gene copy number alterations are predominant in high-grade salivary mucoepidermoid carcinoma irrespective of MAML2 fusion status

Takafumi Nakano, Hidetaka Yamamoto, Kazuki Hashimoto, Sadafumi Tamiya, Hideki Shiratsuchi, Torahiko Nakashima, Ken Ichi Nishiyama, Yuichiro Higaki, Shizuo Komune, Yoshinao Oda

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Aims: In this study, we aimed to investigate the molecular mechanisms underlying the development of mucoepidermoid carcinoma (MEC). Methods and results: In 31 cases, we examined the MAML2 fusion status using reverse transcriptase-polymerase chain reaction, and HER2 and EGFR status using immunohistochemistry and chromogenic in-situ hybridization. MAML2 fusions were detected in 15 (57.7%) of 26 MECs analysed, including 11 of 16 (68.8%) low-grade, two of four (50%) intermediate-grade and two of six (33.3%) high-grade MECs. HER2 gene amplification and an increased EGFR gene copy number (with balanced chromosome 7 high-polysomy) were each detected in four of 28 (14.3%) MECs analysed. Irrespective of MAML2 fusion status, all seven high-grade MECs had an increased gene copy number of either HER2 or EGFR, in a mutually exclusive manner, whereas such abnormalities were extremely rare in low- and intermediate-grade MEC. Conclusions: These results suggest that HER2 or EGFR gene abnormality could play an important role in the development of high-grade MEC, and also in the progression from MAML2 fusion-positive low-/intermediate-grade to high-grade in a subset of MEC. Furthermore, we suggest that high-grade MEC comprises a heterogeneous group of tumours in terms of molecular pathogenesis, in particular MAML2 fusion status.

Original languageEnglish
Pages (from-to)378-392
Number of pages15
Issue number3
Publication statusPublished - Sep 1 2013


All Science Journal Classification (ASJC) codes

  • Pathology and Forensic Medicine
  • Histology

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