Prostate cancer subtyping and differential methylation analysis based on the ETS family of transcription factors fusion genes.

Prostate cancer (PCa) is a highly heterogeneous disease, encompassing various molecular and clinical pathological subtypes. Fusion genes play a facilitating role in the occurrence and progression of PCa. We categorized PCa samples into the ETS family of transcription factors fusion positive and fusion negative subtypes based on fusion genes. This subtyping method is closely related to the epigenomic DNA methylation profiles of PCa, with each sample cluster including more than 85% of the patients. We conducted an analysis of the distribution of the ETS family fusion genes on chromosomes, fusion modes within reading frames, and predictions of structural domains. Among these, the highest frequency of the ETS family related fusion genes occurred on chromosome 21. Compared to the parental genes, fusion genes exhibited new structural domains, such as IG_like, and the most common fusion mode was out-of-frame fusion. The correlation between the methylation levels of hypermethylated CpG sites and the expression levels of their corresponding mRNAs indicates that CD8A and B3GNT5 (with correlations of - 0.388 and - 0.253, respectively) could serve as potential prognostic markers for PCa.

New dual inducible cellular model to investigate temporal control of oncogenic cooperating genes.

The study of cooperating genes in cancer can lead to mechanistic understanding and identifying potential therapeutic targets. To facilitate these types of studies, we developed a new dual-inducible system utilizing the tetracycline- and cumate-inducible systems driving HES3 and the PAX3::FOXO1 fusion-oncogene, respectively, as cooperating genes from fusion-positive rhabdomyosarcoma. With this model, we can independently induce expression of either HES3 or PAX3::FOXO1, as well as simultaneously induce expression of both genes. This new model will allow us to further investigate the cooperation between HES3 and PAX3::FOXO1 including the temporal requirements for genetic cooperation. Functionally, we show that dual-induction of PAX3::FOXO1 and HES3 modifies sphere formation in a HEK293T-based system. More broadly, this lentiviral dual-inducible system can be adapted for any cooperating genes (overexpression or knockdown), allowing for independent, simultaneous, or temporally controlled gene expression.

Pediatric Fibromatosis Lacks the Internal Tandem Duplication of EGFR Seen in Congenital Mesoblastic Nephroma.

Classical and mixed congenital mesoblastic nephroma (CMN) are characterized by an internal tandem duplication (ITD) of the EGFR gene, in contrast to cellular CMN that usually harbors an ETV6::NTRK3 gene fusion. This same fusion occurs in infantile fibrosarcoma, and this tumor can be considered as the soft tissue equivalent of cellular CMN. A soft tissue equivalent of classic/mixed CMN remains undefined at the genetic level. Since classical CMN resembles fibromatosis of soft tissue histologically, we asked whether fibromatosis in children might show EGFR ITD. ITD was investigated using the polymerase chain reaction and primers for exons 18 and 25 of the EGFR gene. Seven of the eight cases of classical or mixed CMN were positive by this approach, but none of the five cellular CMNs. Of 11 cases of fibromatosis (six plantar, two digital, and three desmoid), none were positive for EGFR ITD. Within the limits of this small study, we conclude that pediatric fibromatosis is likely not characterized by EGFR ITD. There are isolated reports of pediatric soft tissue tumors that harbor EGFR ITD, but these have the appearance of infantile fibrosarcoma or mixed CMN rather than fibromatosis. We did not find any such cases, since all 14 cases of infantile fibrosarcoma in our study had an ETV6::NTRK3 fusion. The soft tissue tumors with EGFR ITD are not a morphologic match for the low-grade histology of classical CMN. Whether they have a similar favorable biology or behave more like fibrosarcoma with an ETV6::NTRK3 fusion or an alternative fusion involving other kinases remains to be determined.

Preservation of cfRNA in cytological supernatants for cfDNA & cfRNA double detection in non-small cell lung cancer patients.

BACKGROUD: Supernatants from various cytological samples, including body cavity effusion, sputum, bronchoalveolar lavage fluid (BALF), and needle aspiration, have been validated for detecting genetic alterations using cell-free DNA (cfDNA) in patients with non-small cell lung cancer (NSCLC). However, the sensitivity of fusion variations detection remains challenging. The protection of cell-free RNA (cfRNA) is critical for resolving the issue. METHODS: A protective solution (PS) was applied for preserving cfRNA in cytological supernatant (CS), and the quality of protected cfRNA was assessed by cycle threshold (CT) values from reverse transcription quantitative polymerase chain reaction (RT-qPCR). Furthermore, we collected an additional set of malignant cytological and matched tumor samples from 84 NSCLC patients, cfDNA & cfRNA extraction and double detection for driver gene mutations was validated using the multi-gene mutations detection by RT-qPCR. RESULTS: Under the optimal protection system, 91.0% (101/111) of cfRNA were protected effectively. Among the 84 NSCLC patient samples, seven cytological samples failed the tests. In comparison with tumor samples, the overall sensitivity and specificity of detecting driver genes of supernatant cfDNA and cfRNA were 93.8% (74/77) and 100% (77/77), respectively. Notably, when focusing exclusively on patients with fusion gene changes, both sensitivity and specificity reached 100% (11/11) for EML4-ALK, ROS1, RET fusions, and MET ex14 skipping. CONCLUSION: These findings suggest that cfDNA & cfRNA extraction and double detection strategy recommended in this study improve the accuracy of driver genes mutations test, especially for RNA-based assay.

Clinical relevance and druggability of sole reciprocal kinase fusions: A large-scale study.

BACKGROUND: Building on our prior work that RNA alternative splicing modulates the druggability of kinase fusions, this study probes the clinical significance of sole reciprocal fusions. These rare genomic arrangements, despite lacking kinase domains at the DNA level, demonstrated potential RNA-level druggability in sporadic cases from our prior research. METHODS: Utilizing the large-scale multicenter approach, we performed RNA sequencing and clinical follow-up to evaluate a broad spectrum of kinase fusions, including ALK, ROS1, RET, BRAF, NTRK, MET, NRG1, and EGFR, in 1943 patients. RESULTS: Our findings revealed 51 instances (2.57%) of sole reciprocal fusions, predominantly in lung (57%), colorectal (14%), and glioma (10%) cancers. Comparative analysis with an MSKCC cohort confirmed the prevalence in diverse cancer types and identified unique fusion partners and chromosomal locales. Cross-validation through RNA-NGS and FISH authenticated the existence of functional kinase domains in subsets including ALK, ROS1, RET, and BRAF, which correlated with positive clinical responses to targeted kinase inhibitors (KIs). Conversely, fusions involving EGFR, NRG1, and NTRK1/2/3 generated nonfunctional transcripts, suggesting the need for alternative therapeutic interventions. CONCLUSION: This inaugural multicenter study introduces a novel algorithm for detecting and treating sole reciprocal fusions in advanced cancers, expanding the patient population potentially amenable to KIs.

Case of B-acute lymphoblastic leukaemia with t(1;19)(q23;p13.3) TCF3::PBX1 and co-occurring CBL mutation in an elderly patient.

The t(1;19) (q23;p13) TCF3::PBX1 is a well-described, recurring chromosomal abnormality in B-acute lymphoblastic leukaemia (B-ALL) that has historically been associated with a worse prognosis in paediatric patients. Gene expression profiling has demonstrated that TCF3::PBX1 results in a distinct subtype of B-ALL, leading to its recognition in the most recent WHO and ICC classifications. Though initially believed to be a poor prognostic sign in the adult population, emerging evidence suggests its presence may instead be intermediate or even favourable in B-ALL. However, adults with TCF3::PBX1 are typically younger and often qualify for treatment with paediatric-inspired regimens. Thus, the prognostic significance in this population remains unclear. This translocation appears to be very rare in older adults with B-ALL and its predictive and prognostic nature in this population is unknown. Herein, we explore a case of this translocation occurring in a patient in her 70s. She initially presented to the emergency department with abdominal pain and thrombocytopenia and was subsequently diagnosed with B-ALL. In addition to t(1;19) (q23;p13), a pathologic mutation in the CBL gene was identified. CBL mutations have been implicated in cancer progression and are mostly described in paediatric B-ALL. She was treated with modified Ph-negative EWALL induction (Vincristine, Idarubicin, dexamethasone) and achieved a complete remission. However, she subsequently experienced an early relapse and was refractory to targeted therapy with blinatumomab. After treatment with inotuzumab ozogamicin, she achieved a second complete remission. Unfortunately, she then suffered a central nervous system (CNS) relapse and passed away from complications of her disease. This case serves as an example of the heterogeneous nature of B-ALL. It demonstrates that patients with ostensibly favourable prognostic factors may experience poor response rates to traditional chemotherapy as well as targeted salvage agents. It also illustrates the challenges of treating B-ALL in the elderly population.

Clinicopathological characteristics and genetic features of young and senior Ewing sarcoma patients.

BACKGROUND: Ewing sarcoma (EwS) is a highly malignant and heterogeneous tumor. Exploring clinicopathological characteristics and genetic features of EwS is critical for prognosis and treatment regimen. METHODS: Clinicopathological characteristics and genetic features of young (≤ 30y) and senior (> 30y) EwS patients were analyzed based on histology, phenotype, and next-generation sequencing (NGS) detection. RESULTS: The young group (18/36) presented nontypical EwS histological morphology, whereas the senior group (18/36) presented typical morphology. The prognosis of the young group was found to be worse compared with the senior group for patients without metastasis at the initial diagnosis. DNA- and RNA-based NGS was conducted on 20 extraosseous EwS patients. 16/20 samples demonstrated EWSR1-FLI1 fusion and 4/20 demonstrated EWSR1-ERG fusion. However, 13/16 EWSR1-FLI1fusions were detected both in DNA- and RNA-based NGS, 1/16 was detected only at the DNA level, and 2/16 were detected only at the RNA level. An analysis of the genetic profiles of the EWSR1-FLI1 cases revealed that the young group was inclined to couple with more copy number variations (CNV), such as CCND1, CDK4 amplification, and fusion variations, such as CHEK1-EWSR1, SLIT2-EWSR1, and EWSR1-FAM76B fusion. The senior group was more likely to have SNV or Indel mutations, such as EPHA3 and STAG2 mutations. Moreover, patients with more CNV abnormalities had a worse prognosis than those with predominantly SNP variants. In addition, compared with the senior group, the young group had significantly higher CyclinD1 protein expression. CONCLUSION: Clinicopathological characteristics and genetic features in young and senior EwS patients differed significantly. Targeting cell cycle dysregulation based on age subgroup may be a potential therapeutic strategy for Ewing sarcoma.

Successfully treatment of PLZF-RARα positive acute promyelocytic leukemia by Venetoclax combining with decitabine: a case report and literature review.

INTRODUCTION: Acute promyelocytic leukemia (APL) is mainly due to the chromosome translocation t(15; 17) (q22; q12), leading to the formation of PML-RARα fusion protein. However, some patients carried rare translocation involving RARα gene, and they were referred to as variant APL caused by the RAR family (RARα, RARB, and RARG) and partner genes. PLZF-RARα was a rare type of molecular genetic abnormality with unfavorable prognosis that has been reported in few cases in variant APL. Knowledge of PLZF-RARα (+) APL treatment remains limited understood. CASE REPORT: We presented a case of variant APL in a 47-year-old female, who was PLZF-RARα positive detected by reverse transcription polymerase chain reaction (RT-PCR). The patient did not respond to all-trans retinoic acid (ATRA), idarubicin, and arsenic trioxide (As2O3) combined induction chemotherapy. Then, the patient was treated with Venetoclax combining with decitabine as the salvage therapy and achieved morphological remission and PLZF/RARα gene negative. CONCLUSION: Venetoclax combining with decitabine can be used as an effective therapy in the PLZF-RARα positive APL.

Long-Term Tumor Stability After First-Line Treatment With Larotrectinib in an Infant With NTRK2 Fusion-Positive High-Grade Glioma.

Tissue-agnostic, molecularly targeted therapies are becoming increasingly common in cancer treatment. The molecular drivers of some classes and subclasses of tumors are rapidly being uncovered in an era of deep tumor sequencing occurring at the time of diagnosis. When and how targeted therapies should fit within up-front cytotoxic chemotherapy and radiation paradigms is yet to be determined, because many of them have been studied in single-arm studies in patients with relapsed or refractory cancer. Infant high-grade gliomas (HGGs) are biologically and clinically distinct from older child and adult HGGs, and are divided into 3 molecular subgroups. Group 1 infant HGGs are driven by receptor tyrosine kinase fusions, most commonly harboring an ALK, ROS1, NTRK, or MET fusion. Both larotrectinib and entrectinib are tropomyosin receptor kinase inhibitors with tissue-agnostic approvals for the treatment of patients with solid tumors harboring an NTRK fusion. This report discusses an 11-month-old female who presented with infantile spasms, found to have an unresectable, NTRK fusion-positive infant HGG. Larotrectinib was prescribed when the NTRK fusion was identified at diagnosis, and without additional intervention to date, the patient has continued with stable disease for >3 years. The only adverse event experienced was grade 1 aspartate transaminase and alanine transaminase elevations. The patient has a normal neurologic examination, is developing age-appropriately in all domains (gross motor, fine motor, cognitive, language, and social-emotional). She is no longer on antiseizure medications. To our knowledge, this is the first report of a patient with an infantile HGG receiving targeted therapy as first-line treatment with prolonged stable disease. A prospective study of larotrectinib in patients with newly diagnosed infant HGG is ongoing, and will hopefully help answer questions about durability of response, the need for additional therapies, and long-term toxicities seen with TRK inhibitors.

Concurrent ependymal and ganglionic differentiation in a subset of supratentorial neuroepithelial tumors with EWSR1-PLAGL1 rearrangement.

Neuroepithelial tumors with fusion of PLAGL1 or amplification of PLAGL1/PLAGL2 have recently been described often with ependymoma-like or embryonal histology respectively. To further evaluate emerging entities with PLAG-family genetic alterations, the histologic, molecular, clinical, and imaging features are described for 8 clinical cases encountered at St. Jude (EWSR1-PLAGL1 fusion n = 6; PLAGL1 amplification n = 1; PLAGL2 amplification n = 1). A histologic feature observed on initial resection in a subset (4/6) of supratentorial neuroepithelial tumors with EWSR1-PLAGL1 rearrangement was the presence of concurrent ependymal and ganglionic differentiation. This ranged from prominent clusters of ganglion cells within ependymoma/subependymoma-like areas, to interspersed ganglion cells of low to moderate frequency among otherwise ependymal-like histology, or focal areas with a ganglion cell component. When present, the combination of ependymal-like and ganglionic features within a supratentorial neuroepithelial tumor may raise consideration for an EWSR1-PLAGL1 fusion, and prompt initiation of appropriate molecular testing such as RNA sequencing and methylation profiling. One of the EWSR1-PLAGL1 fusion cases showed subclonal INI1 loss in a region containing small clusters of rhabdoid/embryonal cells, and developed a prominent ganglion cell component on recurrence. As such, EWSR1-PLAGL1 neuroepithelial tumors are a tumor type in which acquired inactivation of SMARCB1 and development of AT/RT features may occur and lead to clinical progression. In contrast, the PLAGL2 and PLAGL1 amplified cases showed either embryonal histology or contained an embryonal component with a significant degree of desmin staining, which could also serve to raise consideration for a PLAG entity when present. Continued compilation of associated clinical data and histopathologic findings will be critical for understanding emerging entities with PLAG-family genetic alterations.

TLE3 Is a Novel Fusion Partner of JAK2 in Myeloid/Lymphoid Neoplasm With Eosinophilia Responding to JAK2 Inhibition.

Chromosomal rearrangements involving Janus kinase 2 (JAK2) are rare but recurrent findings in lymphoid or myeloid neoplasia. Detection of JAK2 fusion genes is important as patients with aberrantly activated JAK2 may benefit from treatment with tyrosine kinase inhibitors such as ruxolitinib. Here, we report a novel fusion gene between the transcriptional co-repressor-encoding gene transducin-like enhancer of split 3 (TLE3) and JAK2 in a patient initially diagnosed with chronic eosinophilic leukemia with additional mutations in PTPN11 and NRAS. The patient was successfully treated with the JAK2 inhibitor ruxolitinib for 8 months before additional somatic mutations were acquired and the disease progressed into an acute lymphoblastic T-cell leukemia/lymphoma. The present case shows similarities to previously reported cases with PCM1::JAK2 and BCR::JAK2 with regard to disease phenotype and response to ruxolitinib, and importantly, provides an example that also patients harboring other JAK2 fusion genes may benefit from treatment with JAK2 inhibitors.

Prion-like domain mediated phase separation of ARID1A promotes oncogenic potential of Ewing's sarcoma.

Liquid-liquid phase separation (LLPS) facilitates the formation of membraneless organelles within cells, with implications in various biological processes and disease states. AT-rich interactive domain-containing protein 1A (ARID1A) is a chromatin remodeling factor frequently associated with cancer mutations, yet its functional mechanism remains largely unknown. Here, we find that ARID1A harbors a prion-like domain (PrLD), which facilitates the formation of liquid condensates through PrLD-mediated LLPS. The nuclear condensates formed by ARID1A LLPS are significantly elevated in Ewing's sarcoma patient specimen. Disruption of ARID1A LLPS results in diminished proliferative and invasive abilities in Ewing's sarcoma cells. Through genome-wide chromatin structure and transcription profiling, we identify that the ARID1A condensate localizes to EWS/FLI1 target enhancers and induces long-range chromatin architectural changes by forming functional chromatin remodeling hubs at oncogenic target genes. Collectively, our findings demonstrate that ARID1A promotes oncogenic potential through PrLD-mediated LLPS, offering a potential therapeutic approach for treating Ewing's sarcoma.

Malignant Epithelioid Mesenchymal Neoplasm with FUS::CREM Gene Fusion Arising in the Tongue: A Case Report Detailing Clinicopathological, Imaging, and Molecular Features.

FUS::CREM fusion is a distinct primary driver in rare neoplasms of the head and neck and other anatomic sites. Herein, we describe the clinicopathological, imaging, and molecular features of a malignant epithelioid mesenchymal neoplasm harboring FUS::CREM fusion, arising in the tongue of a 46-year-old male. Clinically, the patient presented with a left upper neck mass. Imaging revealed a 4.0 cm mass at the left base of tongue. Histologically, the tumor consisted of sheets of loosely cohesive, small round to ovoid cells with moderate cytoplasm, small nuclei with coarse chromatin, frequent nuclear pseudoinclusions, and dense peripheral lymphoplasmacytic and histiocytic infiltrates. Malignant features, including tumor necrosis, perineural invasion, and increased mitotic activity were observed; however, lymphovascular invasion was absent with no evidence metastatic disease in the examined lymph nodes. A comprehensive panel of immunohistochemical stains showed positivity for synaptophysin and ALK, with negative results for all other markers. RNA-based next-generation sequencing using anchored multiplex polymerase chain reaction (PCR) was performed and detected FUS::CREM fusion gene. The patient was treated by excision and postsurgical chemoradiation with no evidence of recurrence after four months. Additional cases supported by comprehensive clinical data collected over an extended period are necessary to precisely characterize epithelioid mesenchymal neoplasms harboring FUS::CREM fusion in the head and neck.

Metastatic Non-Myofibroblastic Sarcoma Harbouring EML4-ALK Fusion-Dramatic Response to ALK Tyrosine Kinase Inhibitors and Development of Resistance Mutations.

BACKGROUND: Anaplastic lymphoma kinase (ALK) rearrangements are rare in non-myofibroblastic sarcoma and there is limited data on the efficacy of ALK tyrosine kinase inhibitors (TKIs) and mechanisms of resistance in these patients. CASE: A 58 year-old man with metastatic non-myofibroblastic sarcoma was found to have an EML4-ALK fusion on molecular sequencing. After progression on first line systemic therapy with doxorubicin, the patient received alectinib, a second generation ALK inhibitor, and had a marked clinical and radiological response. He progressed after 5 months of treatment. Repeat lung biopsy identified the emergence of an ALK I1171N resistance mutation. He was then treated with lorlatinib, again with rapid clinical improvement and significant partial radiological response. He progressed after 4 months, at which time a repeat lung biopsy identified a new ALK kinase domain mutation G1202R. The patient was subsequently treated with chemotherapy, though unfortunately died shortly after due to rapidly progressive disease. CONCLUSION: This case report adds to a body of evidence demonstrating the potential transformative response to targeted therapy in non-lung solid organ tumours harbouring ALK fusions. This is the first description tracking the development of resistance mutations in a patient with non-myofibroblastic sarcoma and questions the utility of the presence of G1202R mutation as a marker of lorlatinib sensitivity in non-lung ALK rearranged tumours, contrary to experience in lung cancer.

Phase separation of PML/RARα and BRD4 coassembled microspeckles governs transcriptional dysregulation in acute promyelocytic leukemia.

In acute promyelocytic leukemia (APL), the promyelocytic leukemia-retinoic acid receptor alpha (PML/RARα) fusion protein destroys PML nuclear bodies (NBs), leading to the formation of microspeckles. However, our understanding, largely learned from morphological observations, lacks insight into the mechanisms behind PML/RARα-mediated microspeckle formation and its role in APL leukemogenesis. This study presents evidence uncovering liquid-liquid phase separation (LLPS) as a key mechanism in the formation of PML/RARα-mediated microspeckles. This process is facilitated by the intrinsically disordered region containing a large portion of PML and a smaller segment of RARα. We demonstrate the coassembly of bromodomain-containing protein 4 (BRD4) within PML/RARα-mediated condensates, differing from wild-type PML-formed NBs. In the absence of PML/RARα, PML NBs and BRD4 puncta exist as two independent phases, but the presence of PML/RARα disrupts PML NBs and redistributes PML and BRD4 into a distinct phase, forming PML/RARα-assembled microspeckles. Genome-wide profiling reveals a PML/RARα-induced BRD4 redistribution across the genome, with preferential binding to super-enhancers and broad-promoters (SEBPs). Mechanistically, BRD4 is recruited by PML/RARα into nuclear condensates, facilitating BRD4 chromatin binding to exert transcriptional activation essential for APL survival. Perturbing LLPS through chemical inhibition (1, 6-hexanediol) significantly reduces chromatin co-occupancy of PML/RARα and BRD4, attenuating their target gene activation. Finally, a series of experimental validations in primary APL patient samples confirm that PML/RARα forms microspeckles through condensates, recruits BRD4 to coassemble condensates, and co-occupies SEBP regions. Our findings elucidate the biophysical, pathological, and transcriptional dynamics of PML/RARα-assembled microspeckles, underscoring the importance of BRD4 in mediating transcriptional activation that enables PML/RARα to initiate APL.

NUP98::NSD1 and FLT3/ITD co-expression is an independent predictor of poor prognosis in pediatric AML patients.

OBJECTIVE: Patients who carry NUP98::NSD1 or FLT3/ITD mutations are reported to have poor prognosis. Previous studies have confidently reported that the poor outcome in younger AML patients is owning to dual NUP98::NSD1 and FLT3/ITD positivity, with a high overlap for those two genetic lesions. In this study, we assessed the prognostic value of the presence of both NUP98::NSD1 and FLT3/ITD in pediatric AML patients. METHODS: We screened a large cohort of 885 pediatric cases from the COG-National Cancer Institute (NCI) TARGET AML cohort and found 57 AML patients with NUP98 rearrangements. RESULTS: The frequency of NUP98 gene fusion was 10.8% in 529 patients. NUP98::NSD1 fusion was the most common NUP98 rearrangement, with a frequency of 59.6%(34 of 57). NUP98::NSD1 -positive patients who carried FLT3/ITD mutations had a decreased CR1 or CR2 rate than those patients carried FLT3/ITD mutation alone (P = 0.0001). Moreover, patients harboring both NUP98::NSD1 fusion and FLT3/ITD mutation exhibited inferior event-free survival (EFS, P < 0.001) and overall survival (OS, P = 0.004) than patients who were dual negative for these two genetic lesions. The presence of only NUP98::NSD1 fusion had no significant impact on EFS or OS. We also found that cases with high FLT3/ITD AR levels ( > = 0.5) with or without NUP98::NSD1 had inferior prognosis. Multivariate analysis demonstrated that the presence of both NUP98::NSD1 and FLT3/ITD was an independent prognostic factors for EFS (hazard ratio: 3.2, P = 0.001) in patients with pediatric AML. However, there was no obvious correlation with OS (hazard ratio: 1.3, P = 0.618). Stem cell transplantation did not improve the survival rate of cases with NUP98 fusion or NUP98::NSD1 AML in terms of EFS or OS. CONCLUSION: Presence of both NUP98::NSD1 and FLT3/ITD was found to be an independent factor for dismal prognosis in pediatric AML patients. Notably, lack of FLT3/ITD mutations in NUP98::NSD1 -positive patients did not retain its prognostic value.

Outcome-oriented clinicopathological reappraisal of sinonasal adenoid cystic carcinoma with broad morphological spectrum and high MYB::NFIB prevalence.

Adenoid cystic carcinoma (AdCC) is a salivary gland neoplasm that infrequently appears in the sinonasal region. The aim of this study was to evaluate the outcome and clinicopathological parameters of sinonasal AdCC. A retrospective analysis was conducted on all cases of AdCC affecting the nasal cavity or paranasal sinuses between 2000 and 2018 at the University Hospital Zurich. Tumor material was examined for morphological features and analyzed for molecular alterations. A total of 14 patients were included. Mean age at presentation was 57.7 years. Sequencing revealed MYB::NFIB gene fusion in 11/12 analyzable cases. Poor prognostic factors were solid variant (p < 0.001), histopathological high-grade transformation (p < 0.001), and tumor involvement of the sphenoid sinus (p = 0.02). The median recurrence-free survival (RFS) and OS were 5.2 years and 11.3 years. The RFS rates at 1-, 5-, and 10-year were 100%, 53.8%, and 23.1%. The OS rates at 1-, 5-, and 10- years were 100%, 91.7%, and 62.9%, respectively. In Conclusion, the solid variant (solid portion > 30%), high-grade transformation, and sphenoid sinus involvement are negative prognostic factors for sinonasal AdCC. A high prevalence of MYB::NFIB gene fusion may help to correctly classify diagnostically challenging (e.g. metatypical) cases.