Examination of the CRTC1/3-MAML2 fusion gene showed no relation between SRCC of primary unknown with metastasis to the cervical lymph node and MEC of the parotid gland.
Rearrangement of mastermind like transcriptional coactivator 2 (MAML2) (11q21) gene was shown to be present in tumor cells by fluorescence in situ hybridization, supporting the diagnosis of a low-grade Warthin-like mucoepidermoid carcinoma.
CRTC1-MAML2 fusion is often detected in low- or intermediate-grade salivary mucoepidermoid carcinoma (MEC), and it is associated with a favorable clinical course.
We present 2 variants of MEC for which MAML2 studies were crucial in establishing a diagnosis: a previously undescribed ciliated variant, and the recently described Warthin-like variant.
Tumor categories as described by the World Health Organization reflect, in part, a true genetic heterogeneity (e.g., translocations involving CRTC1 and CRTC3-MAML2 genes in mucoepidermoid carcinoma and MYB-NFIB fusion in adenoid cystic carcinoma).
The CRTC1-MAML2 fusion gene resulting from a t(11;19)(q21;p13) translocation, is now known to be a feature of both low-grade and high-grade mucoepidermoid carcinomas associated with improved survival.
We found that LINC00473 transcription was significantly induced in human CRTC1-MAML2-positive MEC cell lines and primary MEC tumors, and was tightly correlated with the CRTC1-MAML2 RNA level.
The present study reports a case of MEC harboring a mastermind-like transcriptional coactivator 2 (<i>MAML2</i>) gene translocation in the sublingual gland.
Using MAML2 fluorescence in situ hybridization (FISH), a total of 49 MEC cases were separated into MAML2 fusion-positive (32 cases) and MAML2 fusion-negative groups (17 cases).
Hence, gene rearrangements such as CRTC1-MAML2 in mucoepidermoid carcinomas have shown excellent specificity, and more than that, it has been strongly correlated with low-grade tumors and consequently with an increased survival rate and better prognosis of patients affected by neoplasms carrying this translocation.
Although the incidence of this fusion in mucoepidermoid carcinoma varies, it is generally accepted that more than 50% of this entity manifest the CRTC1-MAML2.
Amphiregulin (AREG), an epidermal growth factor receptor (EGFR) ligand, has been shown to be a downstream target of CRTC1-MAML2 fusion, and to play a role in tumor growth and survival in CRTC1-MAML2-positive MEC cell lines.