Gene Summary

Gene:MAML2; mastermind like transcriptional coactivator 2
Aliases: MAM2, MAM3, MAM-3, MLL-MAML2
Summary:The protein encoded by this gene is a member of the Mastermind-like family of proteins. All family members are proline and glutamine-rich, and contain a conserved basic domain that binds the ankyrin repeat domain of the intracellular domain of the Notch receptors (ICN1-4) in their N-terminus, and a transcriptional activation domain in their C-terminus. This protein binds to an extended groove that is formed by the interaction of CBF1, Suppressor of Hairless, LAG-1 (CSL) with ICN, and positively regulates Notch signaling. High levels of expression of this gene have been observed in several B cell-derived lymphomas. Translocations resulting in fusion proteins with both CRTC1 and CRTC3 have been implicated in the development of mucoepidermoid carcinomas, while a translocation event with CXCR4 has been linked with chronic lymphocytic leukemia (CLL). Copy number variation in the polyglutamine tract has been observed. [provided by RefSeq, Jan 2015]
Databases:OMIM, HGNC, Ensembl, GeneCard, Gene
Protein:mastermind-like protein 2
Source:NCBIAccessed: 31 August, 2019


What does this gene/protein do?
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Pathways:What pathways are this gene/protein implicaed in?
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Cancer Overview

Research Indicators

Publications Per Year (1994-2019)
Graph generated 31 August 2019 using data from PubMed using criteria.

Literature Analysis

Mouse over the terms for more detail; many indicate links which you can click for dedicated pages about the topic.

  • Zinc Finger E-box-Binding Homeobox 1
  • Disease-Free Survival
  • Messenger RNA
  • Gene Fusion
  • FISH
  • Lung Cancer
  • Biomarkers, Tumor
  • Differential Diagnosis
  • Salivary Gland Cancer
  • Carcinoma
  • Salivary Glands
  • Immunohistochemistry
  • Mutation
  • Parotid Neoplasms
  • Cervical Cancer
  • Carcinoma, Mucoepidermoid
  • Gene Expression Profiling
  • DNA-Binding Proteins
  • Membrane Proteins
  • Chromosome 11
  • Breast Cancer
  • Tumor Suppressor Proteins
  • Transcription Factors
  • Neoplasm Grading
  • Biopsy
  • Sweat Gland Neoplasms
  • Adenoid Cystic Carcinoma
  • Cancer Gene Expression Regulation
  • Adenolymphoma
  • Karyotyping
  • Adolescents
  • Oncogene Fusion Proteins
  • Chromosome 19
  • Cancer DNA
  • Childhood Cancer
  • Gene Rearrangement
  • Nuclear Proteins
  • Staging
  • Genetic Predisposition
Tag cloud generated 31 August, 2019 using data from PubMed, MeSH and CancerIndex

Specific Cancers (6)

Data table showing topics related to specific cancers and associated disorders. Scope includes mutations and abnormal protein expression.

Note: list is not exhaustive. Number of papers are based on searches of PubMed (click on topic title for arbitrary criteria used).

Latest Publications: MAML2 (cancer-related)

Zhang D, Liao X, Tang Y, et al.
Warthin-like Mucoepidermoid Carcinoma of the Parotid Gland: Unusual Morphology and Diagnostic Pitfalls.
Anticancer Res. 2019; 39(6):3213-3217 [PubMed] Related Publications
BACKGROUND: Warthin-like mucoepidermoid carcinoma is a newly recognized rare entity and could be misdiagnosed as a benign Warthin tumor. We report such a case of a 36-year-old male who presented with a left parotid gland mass.
CASE REPORT: Fine-needle aspiration showed features suggestive of Warthin tumor. Following parotidectomy, grossly there was a 1.6 cm well-circumscribed multilobular mass with focal areas of cystic change. Microscopically, at low magnification it had histological features resembling Warthin tumor, while lining with squamoid cells with scattered mucocytes demonstrating mild cytologic atypia was observed at high magnification. Immunohistochemically, the tumor cells were positive for p40, p63, cytokeratin 5/6, cytokeratin 7, and cancer antigen 125, but negative for discovered on GIST-1 (DOG1). Mucicarmine stain highlighted intracellular mucin within mucocytes. 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. The patient was disease-free 12 months after surgery.
CONCLUSION: Warthin-like mucoepidermoid carcinoma has not been widely recognized and can be misdiagnosed as Warthin tumor. Testing for MAML2 rearrangement provides essential support for diagnosis in difficult cases.

Picco G, Chen ED, Alonso LG, et al.
Functional linkage of gene fusions to cancer cell fitness assessed by pharmacological and CRISPR-Cas9 screening.
Nat Commun. 2019; 10(1):2198 [PubMed] Free Access to Full Article Related Publications
Many gene fusions are reported in tumours and for most their role remains unknown. As fusions are used for diagnostic and prognostic purposes, and are targets for treatment, it is crucial to assess their function in cancer. To systematically investigate the role of fusions in tumour cell fitness, we utilized RNA-sequencing data from 1011 human cancer cell lines to functionally link 8354 fusion events with genomic data, sensitivity to >350 anti-cancer drugs and CRISPR-Cas9 loss-of-fitness effects. Established clinically-relevant fusions were identified. Overall, detection of functional fusions was rare, including those involving cancer driver genes, suggesting that many fusions are dispensable for tumour fitness. Therapeutically actionable fusions involving RAF1, BRD4 and ROS1 were verified in new histologies. In addition, recurrent YAP1-MAML2 fusions were identified as activators of Hippo-pathway signaling in multiple cancer types. Our approach discriminates functional fusions, identifying new drivers of carcinogenesis and fusions that could have clinical implications.

Yorita K, Nakagawa H, Miyazaki K, et al.
Infarcted Warthin tumor with mucoepidermoid carcinoma-like metaplasia: a case report and review of the literature.
J Med Case Rep. 2019; 13(1):12 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Warthin tumor is a common, benign, painless salivary gland neoplasm. Rarely, Warthin tumors show large areas of squamous metaplasia; such Warthin tumors are called metaplastic or infarcted Warthin tumors because they are occasionally accompanied with tumor necrosis. The histological distinction between mucoepidermoid carcinomas and the metaplastic portions of Warthin tumors can be challenging; without a genetic study, mucoepidermoid carcinomas can be misdiagnosed as metaplastic Warthin tumors. We report a case of infarcted Warthin tumor partly showing mucoepidermoid carcinoma-like epithelial metaplasia. Only two cases of infarcted Warthin tumor similar to our case have been reported.
CASE PRESENTATION: A 69-year-old Japanese man presented with a right parotid tumor. He had noticed the swelling on his right buccal region 1 year previously; the lesion had rapidly enlarged, with associated pain, 1 month previously. A radiological examination revealed a mass in the tail of the right parotid gland. Superficial parotidectomy was performed. On histological examination, the mass showed typical focal features of Warthin tumor; other areas showed coagulation necrosis of the tumor. These areas were surrounded by non-oncocytic epithelium comprising squamous and mucinous epithelial cells. Although cellular atypia of the non-oncocytic epithelium was not observed, a mixture of squamous and mucinous cells and lack of abundant lymphoid tissue mimicked low-grade mucoepidermoid carcinoma. Based on the results of fluorescence in situ hybridization, MAML2 gene rearrangement was not present in the typical portions of Warthin tumor and the mucoepidermoid carcinoma-like lesion. Therefore, a metaplastic or infarcted Warthin tumor was diagnosed. Our patient was disease-free 8 months after surgery.
CONCLUSIONS: Clinicians need to know that pain is a clinical symptom of infarcted/metaplastic Warthin tumor. Pathologists should be aware that a metaplastic Warthin tumor can mimic a low-grade mucoepidermoid carcinoma. Our case showed a mucoepidermoid carcinoma-like lesion that was confined near the area of tumor necrosis, and neither cytological atypia nor apparent invasive growth was present. These findings appeared to be histological clues of a metaplastic Warthin tumor rather than a mucoepidermoid carcinoma. Careful clinicopathological evaluation as well as genetic studies are needed to clarify the distinction between mucoepidermoid carcinoma and metaplastic portions of Warthin tumors.

Bean GR, Krings G, Otis CN, et al.
CRTC1-MAML2 fusion in mucoepidermoid carcinoma of the breast.
Histopathology. 2019; 74(3):463-473 [PubMed] Related Publications
AIMS: Mucoepidermoid carcinomas (MEC) are the most common malignant neoplasms of salivary glands, but are uncommon in other sites. Salivary gland MEC are most frequently associated with CRTC1-MAML2 translocations. Exceedingly rare MEC of the breast demonstrate a basal-like and often triple (oestrogen and progesterone receptor, HER2)-negative immunophenotype, with a single case previously reported to show MAML2 rearrangement, although the fusion partner was not known. Comprehensive genomic studies of breast MEC are lacking. In this study, we analysed the immunophenotype and molecular landscape of two breast MEC to elucidate the pathogenesis of these rare tumours.
METHODS AND RESULTS: Two breast MEC were subjected to capture-based next-generation DNA sequencing of 479 cancer-related genes. The presence of the CRTC1-MAML2 fusion transcript was interrogated by reverse transcriptase-polymerase chain reaction. In addition, the immunoprofiles of breast MEC were compared to salivary gland MEC. Both breast MEC harboured CRTC1-MAML2 fusions. In contrast to most triple-negative breast carcinomas of no special type, the mutational burden of MEC was very low, with one case demonstrating only an inactivating SETD2 mutation, and the other harbouring no somatic variants in genes on the panel. No copy number alterations were identified. The immunoprofiles of breast and salivary gland MEC were overlapping, but not identical.
CONCLUSIONS: The findings highlight MEC as a breast cancer subtype more closely related to its salivary gland counterpart than to basal-like/triple-negative breast cancers of no special type.

Li X, Guo Z, Liu J, et al.
Clinicopathological characteristics and molecular analysis of primary pulmonary mucoepidermoid carcinoma: Case report and literature review.
Thorac Cancer. 2018; 9(2):316-323 [PubMed] Free Access to Full Article Related Publications
Primary pulmonary mucoepidermoid carcinoma (PMEC) is extremely rare. Herein, we report a case of a 71-year-old male patient with high-grade PMEC involving the right upper lobe that was successfully resected via lobectomy. As a result of invasion into the pleural and paratracheal lymph nodes, four cycles of adjuvant chemotherapy with paclitaxel and carboplatin were administered. There were no signs of relapse during 10 months of follow-up. Furthermore, we reviewed the literature and summarized the surgical approaches, prognostic factors, and underlying genetic mechanisms of PMEC, which will benefit clinical treatment.

Chen Z, Lin S, Li JL, et al.
CRTC1-MAML2 fusion-induced lncRNA LINC00473 expression maintains the growth and survival of human mucoepidermoid carcinoma cells.
Oncogene. 2018; 37(14):1885-1895 [PubMed] Free Access to Full Article Related Publications
Mucoepidermoid carcinoma (MEC) arises in many glandular tissues and contributes to the most common malignant salivary gland cancers. MEC is specifically associated with a unique t(11;19) translocation and the resulting CRTC1-MAML2 fusion is a major oncogenic driver for MEC initiation and maintenance. However, the molecular basis underlying the CRTC1-MAML2 oncogenic functions remains elusive. Through gene expression profiling analysis, we observed that LINC00473, a long non-coding RNA (lncRNA), was the top down-regulated target in CRTC1-MAML2-depleted human MEC cells. LncRNAs belong to a new class of non-coding RNAs with emerging roles in tumorigenesis and progression, but remain poorly characterized. In this study, we investigated the role of LINC00473 in mediating CRTC1-MAML2 oncogenic activity in human MEC. 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. LINC00473 induction was dependent on the ability of CRTC1-MAML2 to activate CREB-mediated transcription. Depletion of LINC00473 significantly reduced the proliferation and survival of human MEC cells in vitro and blocked the in vivo tumor growth in a human MEC xenograft model. RNA in situ hybridization analysis demonstrated a predominantly nuclear localization pattern for LINC00473 in human MEC cells. Furthermore, gene expression profiling revealed that LINC00473 depletion resulted in differential expression of genes important in cancer cell growth and survival. LINC00473 likely regulates gene expression in part through its ability to bind to a cAMP signaling pathway component NONO, enhancing the ability of CRTC1-MAML2 to activate CREB-mediated transcription. Our overall results demonstrate that LINC00473 is a downstream target and an important mediator of the CRTC1-MAML2 oncoprotein. Therefore, LINC00473 acts as a promising biomarker and therapeutic target for human CRTC1-MAML2-positive MECs.

Yabuki K, Matsuyama A, Shiba E, et al.
Sclerosing Mucoepidermoid Carcinoma in the Parotid Gland With CRTC1-MAML2 Fusion: A Case Report.
Int J Surg Pathol. 2018; 26(3):250-255 [PubMed] Related Publications
In this article, we report a case of sclerosing mucoepidermoid carcinoma (MEC) arising in the parotid gland, with CRTC1-MAML2 gene fusion. A 73-year-old woman with a mass in the right parotid region was referred to our hospital. Radiological imaging tests revealed a well-defined mass, measuring 25 mm in diameter, with foci of calcification in the deep lobe of the parotid gland, extending to the parapharyngeal space. Microscopically, the tumor was composed of a proliferation of atypical glandular epithelial cells having intracytoplasmic mucin, squamoid cells, and intermediate cells arranged in nests embedded in a fibrosclerotic stroma, associated with a dense chronic inflammatory infiltrate containing immunoglobulin G4-immunoreactive plasma cells. Reverse transcription-polymerase chain reaction analysis using a formalin-fixed, paraffin-embedded tumor tissue specimen revealed the CRTC1-MAML2 fusion gene transcript. This is the first report of sclerosing MEC with the detection of the MEC-associated fusion gene, reinforcing a common genetic association between MEC and sclerosing MEC.

Yorita K, Kuroda N, Naroda T, et al.
Penile warty mucoepidermoid carcinoma with features of stratified mucin-producing intra-epithelial lesion and invasive stratified mucin-producing carcinoma.
Histopathology. 2018; 72(5):867-873 [PubMed] Related Publications
AIMS: Stratified mucin-producing intra-epithelial lesion (SMILE) and invasive stratified mucin-producing carcinoma (ISMC) are recently described cervical and penile lesions. We report an unusual case of mixed variant of penile squamous cell carcinomas with warty, usual and mucoepidermoid SMILE/ISMC features.
METHODS AND RESULTS: A 62-year-old Japanese man had a glans penis lesion of one-and-a-half years' duration, suggesting malignancy. Partial penectomy and left inguinal lymphadenectomy were performed. Pathological evaluation revealed a mixed squamous cell carcinoma with warty, mucinous and usual features. The mucinous component resembled mucoepidermoid carcinoma (MEC) and SMILE/ISMC. Glandular differentiation was absent. All the diverse tumour components were negative for p16, which was confirmed by negative human papillomavirus (HPV) genotyping. The mucinous component was diffusely positive for cytokeratin 7 and largely negative for cytokeratin 5 and p63. Fluorescence in-situ hybridisation did not detect rearrangement in the MAML2 or EWSR1 genes. The tumour was pathological stage pT2, pN1 (AJCC prognostic stage group IIIA) and was disease-free 26 months after surgery.
CONCLUSIONS: The lack of glands in the mucinous areas suggested that MEC should be separated from adenosquamous carcinoma (ASC). Penile SMILE/ISMC may occur without dependence upon HPV status. Further studies will be necessary to determine the pathogenesis and definition of penile SMILE/ISMC, the presence of true MEC arising from the glans penis and the clinicopathological differences of penile ASC, MEC and SMILE/ISMC. Herein, we refer to the SMILE-like penile lesion as 'mucinous penile intra-epithelial neoplasia'.

Nagasaki A, Ogawa I, Sato Y, et al.
Central mucoepidermoid carcinoma arising from glandular odontogenic cyst confirmed by analysis of MAML2 rearrangement: A case report.
Pathol Int. 2018; 68(1):31-35 [PubMed] Related Publications
Central mucoepidermoid carcinoma (MEC) poses a diagnostic challenge because of its rarity and histological overlap with glandular odontogenic cyst (GOC). In MEC of both salivary glands and jaws, MAML2 arrangement has been well known as the specific gene alteration. We report a case of central MEC arising from GOC diagnosed by MAML2 fusion gene. A 57-year-old male presented a multilocular cystic lesion in left molar region of the mandible. Histopathologically, multiple cysts lined by thin cuboidal or non-keratinized squamous epithelium with small duct-like structures, mucous cells and ciliated cells were present. It was diagnosed as GOC. The recurrent lesion after nine years showed the proliferation of many cystic and solid nests composed of epidermoid, mucous and intermediated cells. Nested PCR revealed CRTC3-MAML2 fusion gene in the recurrent lesion, but not in the primary one. Similarly, MAML-2 rearrangement by FISH analysis was positive in the recurrent lesion, while negative for the primary one, thus confirming the diagnosis of central MEC arising from GOC. Analysis of MAML2 rearrangement can be used as a supportive evidence to distinguish central MEC from GOC.

Greer RO, Eskendri J, Freedman P, et al.
Assessment of biologically aggressive, recurrent glandular odontogenic cysts for mastermind-like 2 (MAML2) rearrangements: histopathologic and fluorescent in situ hybridization (FISH) findings in 11 cases.
J Oral Pathol Med. 2018; 47(2):192-197 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Glandular odontogenic cyst (GOC) demonstrates a significant predilection toward localized biologic aggressiveness and recurrence. GOC shares certain histopathologic features with intraosseous mucoepidermoid carcinoma (IMEC). The current investigation evaluates a group of recurrent, biologically aggressive GOCs to determine whether any cases demonstrated unique histologic features or mastermind-like2 (MAML2) rearrangements common to IMEC.
METHODS: Microscopic slides from 11 previously diagnosed GOCs were stained with hematoxylin and eosin and assessed by 2 study participants for 10 classic histopathologic features required to establish a diagnosis of GOC. Cases were evaluated utilizing break-apart fluorescent in situ hybridization (FISH) analysis for the presence of MAML2 gene rearrangements. Clinical and demographic data on all patients were recorded.
RESULTS: The mean age for patients included in the study was 55.27 years with a range of 36 to 72 years. The most common presenting symptom was a jaw expansion, and all cysts presented initially as a unilocular or multilocular radiolucency. Cysts displayed a minimum of 6 of 10 histologic parameters necessary for a diagnosis of GOC. One case demonstrated MAML2 rearrangements by FISH. That case also showed marked ciliation of cyst-lining epithelial cells and extensive mucous-secreting goblet cell proliferation.
CONCLUSION: Findings in the current study are in concert with previous investigations, and although this study finds only limited molecular evidence to support the premise that recurrent biologically aggressive GOCs are a precursor to IMEC, detection of MAML2 rearrangements in 1 case suggests that such a theoretic transition, while rare, is possible.

Kuma Y, Yamada Y, Yamamoto H, et al.
A novel fusion gene CRTC3-MAML2 in hidradenoma: histopathological significance.
Hum Pathol. 2017; 70:55-61 [PubMed] Related Publications
Hidradenoma usually presents as a solitary, slow-growing, and solid or cystic nodular lesion, which arises in various anatomical sites. Its diagnosis is occasionally difficult because the tumor shares histological features with other cutaneous appendage tumors. Recently, CRTC1-MAML2 fusion gene was reported in hidradenomas, with the fusion transcript being demonstrated in approximately 50% of cases. However, limited information is available regarding its clinical significance. Here, we investigated the relationship between the fusion gene and clinicohistopathological features. We reviewed 39 cases histologically diagnosed as hidradenoma. Reverse-transcription polymerase chain reaction (RT-PCR) was performed for all 39 cases, and fluorescence in situ hybridization was also performed for the RT-PCR-negative cases. The 39 tumors included 36 clear cell hidradenomas and 3 poroid hidradenomas. The details of the cellular components were as follows: clear cell-dominant type, 9 cases; polygonal cell-dominant type, 21 cases; and equally mixed type, 9 cases. There were no tumors with apparent mucinous cells. There were 8 tumors with prominent cystic change, 2 of which presented apocrine-like decapitated secretion. CRTC1-MAML2 fusion was detected in 10 of the 39 tumors (26%) and CRTC3-MAML2 fusion in 2 of the 39 (5%) by RT-PCR. MAML2 gene rearrangement was detected in 11 of 27 fusion gene-negative cases by fluorescence in situ hybridization. Moreover, neither the fusion genes nor gene rearrangement was detected in prominent cystic tumors and poroid hidradenomas. We conclude that CRTC1/3-MAML2 fusion gene analysis can be a useful method for diagnosing hidradenoma. Considering the histological and genetic similarity to mucoepidermoid carcinoma, hidradenoma may be a cutaneous counterpart of salivary gland mucoepidermoid carcinoma.

Skálová A, Stenman G, Simpson RHW, et al.
The Role of Molecular Testing in the Differential Diagnosis of Salivary Gland Carcinomas.
Am J Surg Pathol. 2018; 42(2):e11-e27 [PubMed] Related Publications
Salivary gland neoplasms are a morphologically heterogenous group of lesions that are often diagnostically challenging. In recent years, considerable progress in salivary gland taxonomy has been reached by the discovery of tumor type-specific fusion oncogenes generated by chromosome translocations. This review describes the clinicopathologic features of a selected group of salivary gland carcinomas with a focus on their distinctive genomic characteristics. Mammary analog secretory carcinoma is a recently described entity characterized by a t(12;15)(p13;q25) translocation resulting in an ETV6-NTRK3 fusion. Hyalinizing clear cell carcinoma is a low-grade tumor with infrequent nodal and distant metastasis, recently shown to harbor an EWSR1-ATF1 gene fusion. 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. A t(6;9)(q22-23;p23-34) translocation resulting in a MYB-NFIB gene fusion has been identified in the majority of adenoid cystic carcinomas. Polymorphous (low-grade) adenocarcinoma and cribriform adenocarcinoma of (minor) salivary gland origin are related entities with partly differing clinicopathologic and genomic profiles; they are the subject of an ongoing taxonomic debate. Polymorphous (low-grade) adenocarcinomas are characterized by hot spot point E710D mutations in the PRKD1 gene, whereas cribriform adenocarcinoma of (minor) salivary glands origin are characterized by translocations involving the PRKD1-3 genes. Salivary duct carcinoma (SDC) is a high-grade adenocarcinoma with morphologic and molecular features akin to invasive ductal carcinoma of the breast, including HER2 gene amplification, mutations of TP53, PIK3CA, and HRAS and loss or mutation of PTEN. Notably, a recurrent NCOA4-RET fusion has also been found in SDC. A subset of SDC with apocrine morphology is associated with overexpression of androgen receptors. As these genetic aberrations are recurrent they serve as powerful diagnostic tools in salivary gland tumor diagnosis, and therefore also in refinement of salivary gland cancer classification. Moreover, they are promising as prognostic biomarkers and targets of therapy.

Rito M, Fonseca I
Salivary Gland Neoplasms: Does Morphological Diversity Reflect Tumor Heterogeneity.
Pathobiology. 2018; 85(1-2):85-95 [PubMed] Related Publications
Salivary gland tumor classification encompasses a vast list of benign and malignant neoplasms. Their morphological diversity is recognized not only between different entities but also within individual tumors. 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). Carcinoma ex pleomorphic adenoma shows diversity in its histological appearance, but recurrent rearrangements on PLAG1 and HMGA2 are common to its benign precursor. More recently, new categories have been defined, like secretory carcinoma with the t(12;15) (p13;q25) ETV6-NTRK3 translocation and clear-cell carcinoma with EWSR1-ATF1 fusion. Recent studies on cribriform adenocarcinoma of minor salivary gland origin and epithelial-myoepithelial carcinoma point to a correlation with their morphological features. All of these advances show that the search of a histogenetic and genetic basis for salivary gland tumors is helping to clarify morphological categories and unraveling new ones. Nevertheless, currently morphology is still the hallmark of tumor classification and the gold standard. The therapeutic options for advanced tumors remain very limited but the discovery of translocation-generated gene fusions and increased knowledge of the genomic information of salivary gland tumors is creating opportunities for the development of specific targeted therapies.

Bishop JA, Cowan ML, Shum CH, Westra WH
MAML2 Rearrangements in Variant Forms of Mucoepidermoid Carcinoma: Ancillary Diagnostic Testing for the Ciliated and Warthin-like Variants.
Am J Surg Pathol. 2018; 42(1):130-136 [PubMed] Free Access to Full Article Related Publications
Mucoepidermoid carcinoma (MEC) is the most common salivary gland malignancy. Recent studies have shown that most MECs harbor gene fusions involving MAML2-an alteration that appears to be specific for MEC, a finding that could be diagnostically useful. While most cases of MEC are histologically straightforward, uncommon variants can cause considerable diagnostic difficulty. 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. All cases of ciliated and Warthin-like MEC were retrieved from the archives of The Johns Hopkins Hospital. Break-apart fluorescence in situ hybridization for MAML2 was performed on all cases. One ciliated MEC and 6 Warthin-like MECs were identified. The ciliated MEC presented as a 4.6 cm cystic lymph node metastasis originating from the tongue base in a 47-year-old woman. The Warthin-like MECs presented as parotid masses ranging in size from 1.2 to 3.3 (mean, 2.7 cm) in 4 women and 2 men. The ciliated MEC consisted of macrocystic spaces punctuated by tubulopapillary proliferations of squamoid cells and ciliated columnar cells. The Warthin-like MECs were comprised of cystic spaces lined by multilayered oncocytic to squamoid cells surrounded by a circumscribed cuff of lymphoid tissue with germinal centers. In these cases, the Warthin-like areas dominated the histologic picture. Conventional MEC, when present, represented a minor tumor component. MAML2 rearrangements were identified in all cases. Warthin-like MEC, and now a ciliated form of MEC, are newly described variants of a common salivary gland carcinoma. Unfamiliarity with these novel forms, unanticipated cellular features (eg, cilia), and morphologic overlap with mundane benign processes (eg, developmental ciliated cysts, Warthin tumor) or other carcinomas (eg, ciliated human papillomavirus-related carcinoma) may render these variants susceptible to misdiagnosis. These unusual variants appear to consistently harbor MAML2 fusions-a finding that establishes a clear link to conventional MEC and provides a valuable adjunct in establishing the diagnosis.

Alexiev BA, Jennings LJ, Samant S, Rao S
Oncocytic papillary cystadenoma with prominent mucinous differentiation of parotid gland: A case report.
Pathol Res Pract. 2017; 213(10):1310-1314 [PubMed] Related Publications
We describe the case of an oncocytic papillary cystadenoma with mucinous differentiation of the parotid gland in a 64-year-old male. Histologically, the tumor exhibited distinctive areas of intracystic papillary growth pattern with microcystic and macrocystic spaces containing mucinous secretions and small crystals. The cyst wall and papillary fronds were lined by oncocytic admixed with numerous mucocytes. Lymphoid tissue and invasive features were not identified. The tumor showed strong expression of CK7 and mammaglobin in oncocytes, and BRST-2 and MUC4 in mucocytes. p63, ER, PR, SOX10, DOG-1, and S100 stains were negative. No rearrangement of the MAML2 gene region or ETV6-NTRK3 fusion transcript was detected. The diagnosis of oncocytic papillary tumor with prominent mucinous differentiation is particularly problematic owing to the large number of potential mimics and should prompt consideration of appropriate molecular studies.

Necchi A, Eigl BJ, Yang ES, et al.
Gene Expression Profiling of Advanced Penile Squamous Cell Carcinoma Receiving Cisplatin-based Chemotherapy Improves Prognostication and Identifies Potential Therapeutic Targets.
Eur Urol Focus. 2018; 4(5):733-736 [PubMed] Article available free on PMC after 01/09/2019 Related Publications
In men with advanced penile squamous cell carcinoma receiving first-line chemotherapy, visceral metastases (VM) and Eastern Cooperative Oncology Group performance status ≥1 are poor prognostic factors for overall survival (OS). We hypothesized that tumor gene expression profiling may enhance prognostic stratification and identify potential therapeutic targets. In this retrospective study, RNA extracted from macrodissected tumors underwent profiling for the expression of 738 genes using NanoString. Univariate and multivariate analyses assessed the association of genes, VM, and performance status with OS. Tumors were available from 25 men who received first-line cisplatin-based chemotherapy. In univariate analysis, upregulated MAML2 (p=0.004), KITLG (p≤0.0001), and JAK1 (p=0.029) genes were associated with poor OS, and upregulated FANCA was associated with better OS (p=0.024). In stepwise multivariate analyses, VM (hazard ratio=12.75, p=0.0001) and MAML2 (hazard ratio=10.411, p=0.003) were associated with poor OS. The presence of none, one, and both of these poor risk factors was associated with significantly different median OS of 18.4 mo, 7.2 mo, and 2.1 mo, respectively. Unsupervised clustering demonstrated two major molecular subtypes with trend for different survivals (p=0.052). Validation of results is necessary. PATIENT SUMMARY: The expression of the MAML2 gene in penile cancers from men receiving first-line cisplatin-based chemotherapy predicted overall survival independent of clinical factors.

Goh GH, Lim CM, Vanacek T, et al.
Spindle Cell Mucoepidermoid Carcinoma of the Palatine Tonsil With CRTC1-MAML2 Fusion Transcript: Report of a Rare Case in a 17-Year-Old Boy and a Review of the Literature.
Int J Surg Pathol. 2017; 25(8):705-710 [PubMed] Related Publications
Mucoepidermoid carcinoma (MEC) with a predominant spindle cell composition occurring in the palatine tonsil is exceedingly rare. We present a case of a 17-year-old boy with an uncommon spindle cell variant of MEC arising in the palatine tonsil. Histologically, the tumor showed a solid, noncystic architecture and was composed of a predominant population of bland spindle to fusiform cells arranged in organoid nests with interspersed goblet cells and focal areas of ductular structures. Reverse transcriptase polymerase chain reaction and fluorescence in situ hybridization (FISH) revealed the presence of a t(11;19) CRTC1-MAML2 gene fusion in this rare variant of MEC. This is the first case report of a spindle cell MEC of the palatine tonsil, with molecular genetic confirmation. It illustrates the importance of awareness and recognition of this uncommon histological variant of MEC, which will help establish appropriate treatment and prognostication.

Busse TM, Roth JJ, Wilmoth D, et al.
Copy number alterations determined by single nucleotide polymorphism array testing in the clinical laboratory are indicative of gene fusions in pediatric cancer patients.
Genes Chromosomes Cancer. 2017; 56(10):730-749 [PubMed] Related Publications
Gene fusions resulting from structural rearrangements are an established mechanism of tumorigenesis in pediatric cancer. In this clinical cohort, 1,350 single nucleotide polymorphism (SNP)-based chromosomal microarrays from 1,211 pediatric cancer patients were evaluated for copy number alterations (CNAs) associated with gene fusions. Karyotype or fluorescence in situ hybridization studies were performed in 42% of the patients. Ten percent of the bone marrow or solid tumor specimens had SNP array-associated CNAs suggestive of a gene fusion. Alterations involving ETV6, ABL1-NUP214, EBF1-PDGFRB, KMT2A(MLL), LMO2-RAG, MYH11-CBFB, NSD1-NUP98, PBX1, STIL-TAL1, ZNF384-TCF3, P2RY8-CRLF2, and RUNX1T1-RUNX1 fusions were detected in the bone marrow samples. The most common alteration among the low-grade gliomas was a 7q34 tandem duplication resulting in a KIAA1549-BRAF fusion. Additional fusions identified in the pediatric brain tumors included FAM131B-BRAF and RAF1-QKI. COL1A1-PDGFB, CRTC1-MAML2, EWSR1, HEY1, PAX3- and PAX7-FOXO1, and PLAG1 fusions were determined in a variety of solid tumors and a novel potential gene fusion, FGFR1-USP6, was detected in an aneurysmal bone cyst. The identification of these gene fusions was instrumental in tumor diagnosis. In contrast to hematologic and solid tumors in adults that are predominantly driven by mutations, the majority of hematologic and solid tumors in children are characterized by CNAs and gene fusions. Chromosomal microarray analysis is therefore a robust platform to identify diagnostic and prognostic markers in the clinical setting.

Menu E, Beaufils N, Usseglio F, et al.
First case of B ALL with KMT2A-MAML2 rearrangement: a case report.
BMC Cancer. 2017; 17(1):363 [PubMed] Article available free on PMC after 01/09/2019 Related Publications
BACKGROUND: A large number of chromosomal translocations of the human KMT2A gene, better known as the MLL gene, have so far been characterized. Genetic rearrangements involving KMT2A gene are frequently involved in lymphoid, myeloid and mixed lineage leukemia. One of its rare fusion partners, the mastermind like 2 (MAML2) gene has been reported in four cases of myeloid neoplasms after chemotherapy so far: two acute myeloid leukemias (AML) and two myelodysplasic syndrome (MDS), and two cases of secondary T-cell acute lymphoblastic leukemia (T-ALL).
CASE PRESENTATION: Here we report the case of a KMT2A - MAML2 fusion discovered by Next-Generation Sequencing (NGS) analysis in front of an inv11 (q21q23) present in a 47-year-old female previously treated for a sarcoma in 2014, who had a B acute lymphoid leukemia (B ALL).
CONCLUSION: It is, to our knowledge, the first case of B acute lymphoblastic leukemia with this fusion gene. At the molecular level, two rearrangements were detected using RNA sequencing juxtaposing exon 7 to exon 2 and exon 9 to intron 1-2 of the KMT2A and MAML2 genes respectively, and one rearrangement using Sanger sequencing juxtaposing exon 8 and exon 2.

Evrard SM, Meilleroux J, Daniel G, et al.
Use of fluorescent in-situ hybridisation in salivary gland cytology: A powerful diagnostic tool.
Cytopathology. 2017; 28(4):312-320 [PubMed] Related Publications
OBJECTIVE: Salivary gland cytology is challenging because it includes a diversity of lesions and a wide spectra of tumours. Recently, it has been reported that many types of salivary gland tumours have specific molecular diagnostic signatures that could be identified by fluorescent in-situ hybridisation (FISH). The aim of the present study was to demonstrate the feasibility and efficiency of FISH on routine cytological salivary gland smears.
METHODS: FISH was conducted on 37 cytological salivary gland smears from 34 patients. According to the cytological diagnosis suspected, MECT1/MAML2 gene fusion and rearrangements of PLAG1, MYB, or ETV6 were analysed. The presence and percentages of cells that had gene rearrangements were evaluated. Results were compared with the histological surgical samples, available from 26 patients.
RESULTS: The PLAG1 rearrangement was observed in 12/20 (60%) cases of pleomorphic adenoma. MECT1/MAML2 gene fusion was observed in 1:2 mucoepidermoid carcinomas but was not observed in five other tumours (two pleomorphic adenomas, one Warthin's tumour, one mammary analogue secretory carcinoma [MASC] and one cystic tumour). MYB rearrangement was observed in 4/4 adenoid cystic carcinomas. ETV6-gene splitting identified one MASC.
CONCLUSION: Overall, FISH had a specificity of 100% and a sensitivity of 66.7%. When FISH and cytological analyses were combined, the overall sensitivity was increased to 93.3%. It can thus be concluded that when the FISH analysis is positive, the extent of surgery could be determined with confidence pre-operatively without needing a diagnosis from a frozen section.

Szymanski LJ, Molas-Torreblanca K, Bawab R, et al.
Bronchial Mucoepidermoid Carcinoma With the Classic MAML2 Gene Rearrangement in a 2-year-old Boy.
Pediatr Dev Pathol. 2018 Sep-Oct; 21(5):480-485 [PubMed] Related Publications
Pulmonary mucoepidermoid carcinoma (PMEC) is rare. To date, primary PMEC has not been reported in a child younger than 3 years of age. We report a case of a 2-year-old boy who presented with 3 episodes of wheezing, cough, and fever over a period of 1 month. Radiologic findings were consistent with foreign body aspiration with consequent bronchial obstruction. Bronchoscopy was performed and attempts to retrieve the foreign body resulted in a biopsy of a fleshy lesion. By histology, the lesion was an epithelial neoplasm comprising cells arranged in a nested pattern. The neoplastic cells were round with round nuclei and amphophilic, vacuolated cytoplasm. Our diagnosis was low-grade salivary gland-type carcinoma of the bronchus. The pneumonectomy specimen showed a well-circumscribed, polypoid intrabronchial mass measuring 2.1 cm in greatest dimension. Histologic examination of the tumor showed an admixture of intermediate cells which were predominant, a small number of mucus cells and rare foci of squamous cells. The final diagnosis rendered was a low-grade mucoepidermoid carcinoma of the bronchus. Accurate diagnosis of PMEC can be challenging on limited biopsy material as seen in the case reported here. The use of molecular studies such as MAML2 gene rearrangement may facilitate diagnosis in difficult cases. Increased awareness of this entity and further molecular studies are needed for a better understanding of the pathogenesis of PMEC. To date, the reported age range for primary bronchial mucoepidermoid carcinoma is between 3 years and 78 years. This case represents the youngest patient reported in the English literature.

Birkeland AC, Foltin SK, Michmerhuizen NL, et al.
Correlation of Crtc1/3-Maml2 fusion status, grade and survival in mucoepidermoid carcinoma.
Oral Oncol. 2017; 68:5-8 [PubMed] Article available free on PMC after 01/09/2019 Related Publications
OBJECTIVE: Mucoepidermoid carcinoma (MEC) is the most common malignant tumor of the salivary glands. Tumor stage and grade have historically been important predictors of survival. An oncogenic CRTC1- or CRTC3-MAML2 gene fusion has been identified in a number of MECs. Historically, these gene fusions have been associated with lower grade tumors and better survival. However, reported gene fusion rates and prognosis varies widely across studies, and have not controlled for tumor grade. We sought to identify gene fusion rates and outcomes in our cohort of MEC patients.
MATERIALS AND METHODS: An IRB-approved retrospective cohort of patients with MEC was identified at the University of Michigan. Clinical, histologic, and outcome data was collected from medical records. RNA was isolated from formalin fixed paraffin-embedded tumor sections, and qRT-PCR was performed to identify CRTC1/3-MAML2 gene fusions. Sanger sequencing of qRT-PCR products was used to confirm gene fusions.
RESULTS: Overall, 90 patient MEC tumors were collected (58 low-grade, 25 intermediate-grade, and 7 high-grade). Gene fusions were identified in 59% (53/90) of tumors. On univariate and bivariate analysis, fusion status did not significantly associate with grade or survival.
CONCLUSION: We have identified a high rate of CRTC1/3-MAML2 gene fusions in a large cohort of MEC. We do not identify any correlation between fusion status with tumor grade or survival. These findings suggest further characterization of MECs is needed before considering the CRTC1/3-MAML2 gene fusion as a prognostic biomarker. Additional genetic drivers may account for survival and grade in MECs.

Oide T, Hiroshima K, Takahashi Y, et al.
Mucoepidermoid carcinoma with extensive spindled morphology and melanocytic marker expression.
Hum Pathol. 2017; 67:181-186 [PubMed] Related Publications
Mucoepidermoid carcinoma (MEC) is the most common malignant neoplasm of the salivary gland. Albeit common, histologic variants have rarely been noted in MEC. Here, we report a 49-year-old man with a sublingual gland tumor. Histologically, the tumor was composed of spindle cells arranged in interlacing fascicules or globular nests. A few bland small glands containing mucous cells were also scattered. The spindle tumor cells completely lacked immunoreactivity for cytokeratin, and exhibited immunoreactivity for vimentin, S-100, HMB-45, Melan A, and SOX10. The tumor was initially suspected to be clear cell sarcoma, malignant melanoma, or perivascular epithelioid cell tumor with a few entrapped nonneoplastic duct epitheliums. However, reverse-transcription polymerase chain reaction revealed the CRTC3-MAML2 fusion gene product diagnostic of MEC. In fact, a very minor component of the epithelial cells was reminiscent of conventional MEC, whereas major spindled tumor cells possessed markedly altered differentiation. This is the first case report of MEC with extensive spindled morphology and melanocytic marker expression.

Berger MH, Kerr DA, Rangel Filho AE, Sargi ZB
Case of parotid mucoepidermoid carcinoma: Expanding the spectrum of von Hippel-Lindau-related neoplasms.
Head Neck. 2017; 39(3):E51-E54 [PubMed] Related Publications
BACKGROUND: von Hippel-Lindau (VHL)-related tumors occurring outside the spectrum of VHL-defining tumors are rare, and mucoepidermoid carcinoma (MEC) in the setting of VHL disease has not been described.
METHODS AND RESULTS: We describe a patient with confirmed VHL mutation who presented with a parotid mass and a history of 2 central nervous system (CNS) hemangioblastomas and 1 pheochromocytoma. Fine-needle aspiration (FNA) of the mass suggested a benign Warthin tumor. The mass was resected and final pathology revealed a low-grade MEC. Fluorescence in situ hybridization for the MECT1/MAML2 fusion gene frequently associated with MEC was performed and was negative. Molecular testing of tumor cells displayed a likely "second hit" VHL gene mutation.
CONCLUSION: There is a possible broader role of VHL mutations in tumorigenesis beyond the development of classically described VHL-defining neoplasms. Our case also demonstrates the importance of always considering the possibility of a parotid malignancy in patients with VHL despite a benign FNA. © 2016 Wiley Periodicals, Inc. Head Neck 39: E51-E54, 2017.

Shah AA, La Fortune K, Miller C, et al.
Thyroid sclerosing mucoepidermoid carcinoma with eosinophilia: a clinicopathologic and molecular analysis of a distinct entity.
Mod Pathol. 2017; 30(3):329-339 [PubMed] Article available free on PMC after 01/09/2019 Related Publications
Sclerosing mucoepidermoid carcinoma with eosinophilia is a rare thyroid neoplasm of uncertain pathogenesis that resembles salivary gland mucoepidermoid carcinoma. This multi-institutional study characterizes the clinicopathologic and molecular features of this tumor by utilizing next-generation sequencing to assess common mutations and gene fusions involved in thyroid carcinogenesis as well as fluorescence in-situ hybridization for MAML2 translocations typical of salivary gland mucoepidermoid carcinoma. Nine cases (6 females and 3 males, mean age: 59 years, range 30-77 years) were identified. All cases were comprised of nests and strands of tumor cells with both squamous and mucinous differentiation embedded in a fibrohyaline stroma with an inflammatory infiltrate replete with eosinophils. All cases were p63 positive, thyroglobulin negative and showed variable expression of TTF-1. All nine cases were negative for MAML2 rearrangements. Five cases successfully tested by next-generation sequencing (ThyroSeq v.2 assay) were negative for mutations and translocations commonly involved in thyroid carcinogenesis. NTRK1 showed overexpression but no evidence of translocation. On follow-up, one patient died of persistent disease, whereas one of four remaining patients with available follow-up (mean: 7.3 years, range 4-11 years) demonstrated recurrence at 4 years. Thus, we show that sclerosing mucoepidermoid carcinoma with eosinophilia appears molecularly and morphologically distinct from follicular and C-cell-derived thyroid tumors as well as from salivary gland mucoepidermoid carcinoma. The overall and recurrence-free survival for these patients may be lower than for other well-differentiated thyroid cancers.

Shinomiya H, Ito Y, Kubo M, et al.
Expression of amphiregulin in mucoepidermoid carcinoma of the major salivary glands: a molecular and clinicopathological study.
Hum Pathol. 2016; 57:37-44 [PubMed] Related Publications
In mucoepidermoid carcinoma (MEC), CRTC1-MAML2 fusion indicates a favorable prognosis. 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. The aim of this study was to characterize the AREG and EGFR expression in the fusion-positive and fusion-negative MEC of the major salivary gland. The AREG and EGFR expression were studied by immunochemistry in 33 MEC cases of the major salivary glands. CRTC1-MAML2 fusion was tested by reverse-transcription polymerase chain reaction (23 CRTC1-MAML2 fusion-positive, 10 fusion-negative). Of 23 fusion-positive cases, AREG and EGFR overexpression were detected in 17 (73.9%) and 14 (60.9%) cases, respectively. Of 10 fusion-negative cases, AREG and EGFR overexpression were detected in 1 (10%) and 3 (30.0%) cases, respectively. There was a positive correlation between CRTC1-MAML2 fusion and AREG overexpression (P < .01), but not between CRTC1-MAML2 fusion and EGFR overexpression. The AREG overexpression was associated with a longer disease-free survival of the MEC patients (P = .042), but EGFR overexpression was not. In this study, we showed that AREG overexpression was detected more frequently in the CRTC1-MAML2 fusion-positive tumors than in fusion-negative tumors. Detection of AREG expression may be useful for identifying CRTC1-MAML2-positive MECs and as a marker for favorable prognosis.

Hsieh MS, Wang H, Lee YH, et al.
Reevaluation of MAML2 fusion-negative mucoepidermoid carcinoma: a subgroup being actually hyalinizing clear cell carcinoma of the salivary gland with EWSR1 translocation.
Hum Pathol. 2017; 61:9-18 [PubMed] Related Publications
Hyalinizing clear cell carcinoma (HCCC) is a rare salivary gland tumor with a specific EWSR1-ATF1 fusion gene and can have mucin production. Mucoepidermoid carcinoma (MEC) with a clear cell component is its morphologic mimic. 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). This study used EWSR1 FISH to investigate MAML2 fusion-negative cases to identify previously unrecognized HCCC. Among 17 MAML2 fusion-negative cases, 3 had rearrangement of the EWSR1 gene and were reclassified as HCCC. Including 5 previously diagnosed HCCC cases, these 8 HCCC cases had a male-to-female ratio of 1:7, and most (7/8) tumors arose from oral minor salivary glands in the oral cavity (tongue base and palate). EWSR1-ATF1 fusion was confirmed by FISH in all 8 HCCC cases. The histologic features between genetically confirmed HCCC and MEC were compared. HCCC was significantly associated with minor salivary gland involvement, a discrepancy between low-grade cytology and intermediate- to high-grade histology using the MEC grading system, and absence of both epidermoid cells with abundant cytoplasm and goblet cells lining cysts or forming clusters. Clear cells and a hyalinized stroma were not specific for HCCC. HCCC may be erroneously classified as MEC because clear cells may be a minor histologic component and mucin production is not uncommon. Previously diagnosed MEC cases should be reevaluated, especially those arising from minor salivary glands or without MAML2 fusion. Careful histologic evaluation with supporting molecular testing can facilitate pathologic diagnoses.

Singchat W, Hitakomate E, Rerkarmnuaychoke B, et al.
Genomic Alteration in Head and Neck Squamous Cell Carcinoma (HNSCC) Cell Lines Inferred from Karyotyping, Molecular Cytogenetics, and Array Comparative Genomic Hybridization.
PLoS One. 2016; 11(8):e0160901 [PubMed] Article available free on PMC after 01/09/2019 Related Publications
Genomic alteration in head and neck squamous cell carcinoma (HNSCC) was studied in two cell line pairs (HN30-HN31 and HN4-HN12) using conventional C-banding, multiplex fluorescence in situ hybridization (M-FISH), and array comparative genomic hybridization (array CGH). HN30 and HN4 were derived from primary lesions in the pharynx and base of tongue, respectively, and HN31 and HN12 were derived from lymph-node metastatic lesions belonging to the same patients. Gain of chromosome 1, 7, and 11 were shared in almost all cell lines. Hierarchical clustering revealed that HN31 was closely related to HN4, which shared eight chromosome alteration cases. Large C-positive heterochromatins were found in the centromeric region of chromosome 9 in HN31 and HN4, which suggests complex structural amplification of the repetitive sequence. Array CGH revealed amplification of 7p22.3p11.2, 8q11.23q12.1, and 14q32.33 in all cell lines involved with tumorigenesis and inflammation genes. The amplification of 2p21 (SIX3), 11p15.5 (H19), and 11q21q22.3 (MAML2, PGR, TRPC6, and MMP family) regions, and deletion of 9p23 (PTPRD) and 16q23.1 (WWOX) regions were identified in HN31 and HN12. Interestingly, partial loss of PTPRD (9p23) and WWOX (16q23.1) genes was identified in HN31 and HN12, and the level of gene expression tended to be the down-regulation of PTPRD, with no detectable expression of the WWOX gene. This suggests that the scarcity of PTPRD and WWOX genes might have played an important role in progression of HNSCC, and could be considered as a target for cancer therapy or a biomarker in molecular pathology.

Kang H, Tan M, Bishop JA, et al.
Whole-Exome Sequencing of Salivary Gland Mucoepidermoid Carcinoma.
Clin Cancer Res. 2017; 23(1):283-288 [PubMed] Article available free on PMC after 01/09/2019 Related Publications
PURPOSE: Mucoepidermoid carcinoma (MEC) is the most common salivary gland malignancy. To explore the genetic origins of MEC, we performed systematic genomic analyses of these tumors.
EXPERIMENTAL DESIGN: Whole-exome sequencing and gene copy-number analyses were performed for 18 primary cancers with matched normal tissue. FISH was used to determine the presence or absence of the MECT1-MAML2 translocation in 17 tumors.
RESULTS: TP53 was the most commonly mutated gene in MEC (28%), and mutations were found only in intermediate- and high-grade tumors. Tumors with TP53 mutations had more mutations overall than tumors without TP53 mutations (P = 0.006). POU6F2 was the second most frequently mutated gene, found in three low-grade MECs with the same in-frame deletion. Somatic alterations in IRAK1, MAP3K9, ITGAL, ERBB4, OTOGL, KMT2C, and OBSCN were identified in at least two of the 18 tumors sequenced. FISH analysis confirmed the presence of the MECT1-MAML2 translocation in 15 of 17 tumors (88%).
CONCLUSIONS: Through these integrated genomic analyses, MECT1-MAML2 translocation and somatic TP53 and POU6F2 mutations appear to be the main drivers of MEC. Clin Cancer Res; 23(1); 283-8. ©2016 AACR.

Lubecka K, Kurzava L, Flower K, et al.
Stilbenoids remodel the DNA methylation patterns in breast cancer cells and inhibit oncogenic NOTCH signaling through epigenetic regulation of MAML2 transcriptional activity.
Carcinogenesis. 2016; 37(7):656-68 [PubMed] Article available free on PMC after 01/09/2019 Related Publications
DNA hypomethylation was previously implicated in cancer progression and metastasis. The purpose of this study was to examine whether stilbenoids, resveratrol and pterostilbene thought to exert anticancer effects, target genes with oncogenic function for de novo methylation and silencing, leading to inactivation of related signaling pathways. Following Illumina 450K, genome-wide DNA methylation analysis reveals that stilbenoids alter DNA methylation patterns in breast cancer cells. On average, 75% of differentially methylated genes have increased methylation, and these genes are enriched for oncogenic functions, including NOTCH signaling pathway. MAML2, a coactivator of NOTCH targets, is methylated at the enhancer region and transcriptionally silenced in response to stilbenoids, possibly explaining the downregulation of NOTCH target genes. The increased DNA methylation at MAML2 enhancer coincides with increased occupancy of repressive histone marks and decrease in activating marks. This condensed chromatin structure is associated with binding of DNMT3B and decreased occupancy of OCT1 transcription factor at MAML2 enhancer, suggesting a role of DNMT3B in increasing methylation of MAML2 after stilbenoid treatment. Our results deliver a novel insight into epigenetic regulation of oncogenic signals in cancer and provide support for epigenetic-targeting strategies as an effective anticancer approach.

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