MAML2 (Mastermind Like Transcriptional Coactivator 2)

Accordingly, molecular analysis of the cases revealed the presence of an in-frame YAP1::MAML2 fusion transcript. To conclude, our cases confirmed that YAP1 fusions are the oncogenic drivers of a subset of adnexal tumors that may harbor poroid, follicular but also sebaceous differentiation.

The diagnosis required pathology and molecular testing. MAML2 rearrangement suggests a better prognosis; further research is needed to elucidate its pathogenesis and improve its treatment.

MAML2 rearrangement was detected in all cases by FISH, suggesting it may be a defining feature of breast HA. Because breast HA frequently mimics malignancy and is often diagnosed only after excision, heightened awareness and recognition of its distinctive clinicopathologic and molecular features are essential to prevent overtreatment.

The absence of the common MEC-associated fusion gene may indicate a more aggressive clinical course. Further accumulation of cases with detailed molecular characterization is crucial to clarify the pathogenesis, behavior, and optimal management strategies for this rare entity.

Cancer surgery, radiotherapy, parotidectomy, neck dissection, chemotherapy, and cisplatin were the keywords of treatment...There have always been the common keywords such as pathology, tumor marker, immunohistochemistry, Ki-67, CRTC1, MAML2, gene fusion, and fluorescence in situ hybridization (FISH). This study for the first time elucidated the current scenario and scientometric characteristics of MEC, and would help in improving in reciprocal collaboration and provide helpful guidance for further research.

Co-existent PTC, immunopositivity for thyroid-differentiation markers, and the genetic profile confirm a squamoglandular metaplasia of follicular cells as the origin. The absence of MAML2 fusion questions its WHO categorization as a "salivary gland-type carcinoma." Detailed molecular profiling, while contributing to a better understanding of the pathogenesis of this enigmatic neoplasm, also helped decipher potentially actionable genetic variants.

This case series aims to elucidate the clinicopathological and molecular characteristics of UCMEC to improve diagnostic accuracy. Accurate preoperative or intraoperative distinction from benign lesions and correct grading are paramount for determining the appropriate surgical scope and optimizing patient prognosis.

It did not show C19MC amplification or DICER1 mutation, yet it clustered within the ETMR non-C19MC-altered methylation class of the Heidelberg classifier (V12.5) and the ETMR-DICER class of the NIH classifier. Additionally, a YAP1::MAML2 fusion was identified, a finding not yet associated with these methylation classes.

Comprehensive SalvGlandDx v2 RNA sequencing demonstrated high feasibility and substantial diagnostic and clinical utility in salivary gland tumors, resolving morphological and immunohistochemically ambiguous cases. In a subset of patients, use of the analysis also influenced clinical management highlighting the value of integrating RNA sequencing into routine diagnostic work-up of the varied and challenging salivary gland tumors.

Features suggestive of MEC include complex branched glandular structures and subtle cytologic atypia. We emphasize the importance of incorporating MAML2 molecular testing into diagnostic algorithms for accurate classification, particularly in challenging lesions with lymphoid-rich stroma.

Moreover, MAML2-fused cases might be confused with variant or high-grade mucoepidermoid carcinomas, as they share squamous phenotype and MAML2 rearrangements. The biology of bland cases and their nosology (benign vs low-grade malignant) remain to be further characterized.