Detecting MYB and MYBL1 fusion genes in tracheobronchial adenoid cystic carcinoma by targeted RNA-sequencing

A rare case of hyalinizing clear cell carcinoma of the tongue root: A case report and literature review

The present study describes a rare case of hyalinizing clear cell carcinoma (HCCC) of the tongue root and provides an analysis and review of the relevant literature to improve the understanding of its diagnosis and treatment. Clinical imaging and pathological data from a patient with primary HCCC of the tongue root were summarized, and previously published studies were reviewed through a literature search. The common symptoms, treatment strategies and prognoses reported in the literature were compared. A total of 16 cases of primary HCCC of the tongue were retrieved. Histologically, these cases had tumors characterized by clear cells arranged in sheets, nests and cords within the fibrous interstitium surrounding tumor cells, with round to oval cell nuclei occasionally containing small or inconspicuous nucleoli. Immunohistochemistry showed positive tumor cell staining for cytokeratin (CK)5/6, CK7 and p63, and negative for S-100, smooth muscle actin and calponin. Clinical symptoms included dysphagia, a painless mass, tongue root ulceration and a foreign body sensation in the throat. Treatment strategies included surgery, radiation therapy, repair and reconstruction, with no local recurrence or metastasis at any follow-up point. The present findings indicated that HCCC of the salivary glands is an inert malignant tumor, and a good prognosis can be achieved with both surgical resection and radiation therapy.

PHF1::TFE3-positive fibromyxoid sarcoma? Report of 2 cases and review of 13 cases of PHF1::TFE3-positive ossifying fibromyxoid tumor in the literature

OBJECTIVES

Ossifying fibromyxoid tumor (OFMT) is a rare soft tissue neoplasm of uncertain histogenesis. Most OFMTs have benign behavior, and many harbor gene fusions involving the PHD finger protein 1 (PHF1), such as EP400::PHF1, MEAF6::PHF1, EPC1::PHF1, and PHF1::TFE3. The PHF1::TFE3 fusion is unique because PHF1 is at 5' instead of residing at 3' in the other fusions. In this study, we describe 2 cases of OFMT harboring PHF1::TFE3 fusions and review 13 published cases.

METHODS

Two cases of PHF1::TFE3-positive OFMT were investigated using RNA Next-Generation Sequencing and immunohistochemistry.

RESULTS

Most (12/15) of the PHF1::TFE3 OFMTs we studied were located at proximal and distal extremities, with a multinodular growth pattern. Only 1 case (1/10) had a shell of bone at the periphery. Areas morphologically similar to sclerosing epithelioid fibrosarcoma or low-grade fibromyxoid sarcoma were found in 8 of 12 (66.7%) cases. Eleven cases (11/15 [73.3%]) were regarded as malignant based on more than 2/50 high-power field mitotic figures, increased cellularity, or the presence of necrosis. Among the 9 cases with follow-up data, 2 patients died of disease (with metastases), 1 patient is alive with metastases, and 1 patient had multiple local recurrences.

CONCLUSIONS

Because PHF1 is located at 3' in all the PHF1 fusions in OFMTs except PHF1::TFE3, the different driver molecular alterations suggest that OFMTs with 3'-PHF1 fusions and OFMTs with PHF1::TFE3 are different tumors. Immunohistochemistry confirmed TFE3 expression in all PHF1::TFE3 OFMTs. Because PHF1::TFE3-positive OFMTs have increased mitotic figures and tumor cellularity, with a high rate of metastasis, using the name PHF1::TFE3 positive fibromyxoid sarcoma may be appropriate.

Primary pulmonary adenoid cystic carcinoma: A study of clinicopathological features and molecular alterations in twenty-one cases

BACKGROUND

Primary pulmonary adenoid cystic carcinoma (PACC) is a rare malignant tumor. Despite the growing sophistication of ACC research, scant studies have delved into the unique molecular alterations of ACC originating from the lung and the clinical features associations.

METHOD

Paraffin-embedded specimens of primary PACC tissues pathologically confirmed at the Affiliated Hospital of Qingdao University within the past decade were collected. We comprehensively evaluated the diversity of molecular alterations in PACC using immunohistochemistry (IHC) staining, fluorescence in-situ hybridization (FISH), and next-generation sequencing (NGS). Furthermore, the potential correlations between MYB rearrangement status and clinicopathological features were thoroughly analyzed.

RESULT

Twenty-one specimens of primary PACC were collected, including eighteen of the typical type and three of the solid-basaloid type. Fifteen (71.4 %) specimens exhibited positive MYB staining and MYB rearrangements. Notably, neither clinicopathological parameters nor MYB rearrangement predicted patients' overall survival (OS). However, MYB non-rearrangement was associated with a significantly higher rate of lymph node metastasis (75 % vs. 8.3 %, P = 0.027).

CONCLUSION

Investigating the heterogeneity and multimolecular characteristics of PACC based on different pathological types emerges as a potentially innovative strategy to pinpoint suitable candidates for targeted therapies.

Adenoid Cystic Carcinoma of the Vulva and Vagina: A Clinicopathologic, Immunohistochemical, and Molecular Characterization of Five Cases

Adenoid cystic carcinoma (ACC) is a rare neoplasm most frequently observed in the salivary glands, that can occur in other organs, including the vulva and vagina. Oncogenic mechanisms involving MYB, NFIB , and MYB-NFIB rearrangements have been described, but evidence in the vulva and vagina remains scarce. Our aim is to report the clinicopathologic features, immunohistochemical, and molecular findings in a series of vulvar and vaginal ACCs. Five cases were included. Medical records and slides were reviewed. Formalin-fixed paraffin-embedded material was available in 4 cases, where additional immunohistochemical and molecular studies were carried out. Fluorescence in situ hybridization using MYB, MYBL1 , and NFIB bacterial artificial chromosome-clones break-apart and MYB::NFIB BAC-clones fusion probes was performed. The patients' mean age at diagnosis was 52 years. Tumor size ranged from 0.5 to 5 cm. Microscopic examination revealed tubular, cribriform, and solid patterns. Perineural invasion was seen in 4 cases. Patients were treated with surgery, some with adjuvant radiation therapy. During follow-up (mean: 11 yr), 4 patients developed local recurrences. Recently, one of these patients developed pulmonary disease. Cam 5.2, CK5/6, CD117, and DOG-1 were positive in all 4 cases and S100 and calponin were positive in 3 cases. MYB rearrangement was present in 3 cases, including one with concurrent MYB amplification. There were no MYBL1 or NFIB rearrangements and no MYB :: NFIB fusions. Our findings corroborate that the histologic, immunohistochemical, and oncogenic background is similar between ACCs of the lower female genital tract and ACCs elsewhere, although the canonical MYB::NFIB fusion seems to be a less common finding in this location.

Primary tracheal adenoid cystic carcinoma: A case report and analysis of the tumor immune microenvironment using single cell RNA sequencing

BACKGROUND

Tracheal adenoid cystic carcinoma (ACC) is a slow growing yet aggressive malignancy with high rates of local recurrence as well as distant metastasis. Tracheal ACC exhibit a low mutation burden along with high mutational diversity, and generally do not respond well to chemotherapeutics.

METHODS

We present a rare case of primary tracheal ACC initially presenting with nonspecific cervicalgia and globus sensation that was ultimately treated with tracheal resection followed by chemoradiation. Immune profiling of intratumoral T-cell receptor (TCR) repertoire was subsequently performed using single cell RNA sequencing (scRNAseq).

RESULTS

We describe a rare case of primary tracheal adenoid cystic carcinoma highlighting several management principles as well as providing new insights into intratumor T cell populations.

CONCLUSIONS

Primary tracheal ACC is most commonly treated with surgical resection followed by adjuvant therapy. Further characterization of the tumor immune microenvironment is necessary to better understand ACC disease biology and to identify potential therapeutic targets.

Downregulation of MYBL1 in endothelial cells contributes to atherosclerosis by repressing PLEKHM1-inducing autophagy

MYBL1 is a strong transcriptional activator involved in the cell signaling. However, there is no systematic study on the role of MYBL1 in atherosclerosis. The aim of this study is to elucidate the role and mechanism of MYBL1 in atherosclerosis. GSE28829, GSE43292 and GSE41571 were downloaded from NCBI for differentially expressed analysis. The expression levels of MYBL1 in atherosclerotic plaque tissue and normal vessels were detected by qRT-PCR, Western blot and Immunohistochemistry. Transwell and CCK-8 were used to detect the migration and proliferation of HUVECs after silencing MYBL1. RNA-seq, Western blot, qRT-PCR, Luciferase reporter system, Immunofluorescence, Flow cytometry, ChIP and CO-IP were used to study the role and mechanism of MYBL1 in atherosclerosis. The microarray data of GSE28829, GSE43292, and GSE41571 were analyzed and intersected, and then MYBL1 were verified. MYBL1 was down-regulated in atherosclerotic plaque tissue. After silencing of MYBL1, HUVECs were damaged, and their migration and proliferation abilities were weakened. Overexpression of MYBL1 significantly enhanced the migration and proliferation of HUVECs. MYBL1 knockdown induced abnormal autophagy in HUVEC cells, suggesting that MYBL1 was involved in the regulation of HUVECs through autophagy. Mechanistic studies showed that MYBL1 knockdown inhibited autophagosome and lysosomal fusion in HUVECs by inhibiting PLEKHM1, thereby exacerbating atherosclerosis. Furthermore, MYBL1 was found to repress lipid accumulation in HUVECs after oxLDL treatment. MYBL1 knockdown in HUVECs was involved in atherosclerosis by inhibiting PLEKHM1-induced autophagy, which provided a novel target of therapy for atherosclerosis.

Novel MIR143HG::PLAG1 gene fusion identified in a rectal myxoid leiomyosarcoma

Myxoid leiomyosarcoma (MLS) is a rare but well-documented tumor that often portends a poor prognosis compared to the conventional leiomyosarcoma. This rare sarcoma has been reported in the uterus, external female genitalia, soft tissue, and other locations. However, a definite rectal MLS has not been reported. Recently five cases of MLS were reported to harbor PLAG1 fusions (TRPS1::PLAG1, RAD51B::PLAG1, and TRIM13::PLAG1). In this report, we present a case of rectal MLS with a novel MIR143HG::PLAG1 fusion detected by RNA next-generation sequencing.

Current diagnosis and treatment of salivary gland-type tumors of the lung

Salivary gland-type tumors of the lung are thought to originate from the submucosal exocrine glands of the large airways. Due to their rare occurrence, reports of their study are limited to small-scale or case reports. Therefore, daily clinical practices often require a search for previous reports. In the last 20 years, several genetic rearrangements have been identified, such as MYB::NF1B rearrangements in adenoid cystic carcinoma, CRTC1::MAML2 rearrangements in mucoepidermoid carcinoma, EWSR1::ATF1 rearrangements in hyalinizing clear cell carcinoma and rearrangements of the EWSR1 locus or FUS (TLS) locus in myoepithelioma and myoepithelial carcinoma. These molecular alterations have been useful in diagnosing these tumors, although they have not yet been linked to molecularly targeted therapies. The morphologic, immunophenotypic, and molecular characteristics of these tumors are similar to those of their counterparts of extrapulmonary origin, so clinical and radiologic differential diagnosis is required to distinguish between primary and metastatic disease of other primary sites. However, these molecular alterations can be useful in differentiating them from other primary lung cancer histologic types. The management of these tumors requires broad knowledge of the latest diagnostics, surgery, radiotherapy, bronchoscopic interventions, chemotherapy, immunotherapy as well as therapeutic agents in development, including molecularly targeted agents. This review provides a comprehensive overview of the current diagnosis and treatment of pulmonary salivary gland tumors, with a focus on adenoid cystic carcinoma and mucoepidermoid carcinoma, which are the two most common subtypes.

Characterization of MYBL1 Gene in Triple-Negative Breast Cancers and the Genes' Relationship to Alterations Identified at the Chromosome 8q Loci

The MYBL1 gene is a strong transcriptional activator involved in events associated with cancer progression. Previous data show MYBL1 overexpressed in triple-negative breast cancer (TNBC). There are two parts to this study related to further characterizing the MYBL1 gene. We start by characterizing MYBL1 reference sequence variants and isoforms. The results of this study will help in future experiments in the event there is a need to characterize functional variants and isoforms of the gene. In part two, we identify and validate expression and gene-related alterations of MYBL1, VCIP1, MYC and BOP1 genes in TNBC cell lines and patient samples selected from the Breast Invasive Carcinoma TCGA 2015 dataset available at cBioPortal.org. The four genes are located at chromosomal regions 8q13.1 to 8q.24.3 loci, regions previously identified as demonstrating a high percentage of alterations in breast cancer. We identify alterations, including changes in expression, deletions, amplifications and fusions in MYBL1, VCPIP1, BOP1 and MYC genes in many of the same patients, suggesting the panel of genes is involved in coordinated activity in patients. We propose that MYBL1, VCPIP1, MYC and BOP1 collectively be considered as genes associated with the chromosome 8q loci that potentially play a role in TNBC pathogenesis.

Recent developments in the pathology of primary pulmonary salivary gland-type tumours

Primary pulmonary salivary gland-type tumours are rare neoplasms that are thought to arise from seromucinous glands that are located in the submucosa of large airways. These neoplasms have clinical and pathologic features that are distinct from other pulmonary neoplasms. The majority of primary pulmonary salivary gland-type tumours are malignant, with the most common entities being mucoepidermoid carcinoma, adenoid cystic carcinoma, and epithelial-myoepithelial carcinoma. Less commonly seen are myoepithelial carcinoma, hyalinizing clear cell carcinoma, acinic cell carcinoma, secretory carcinoma, salivary duct carcinoma, intraductal carcinoma, and polymorphous adenocarcinoma. Benign salivary gland-type tumours of the lung include pleomorphic adenoma and sialadenoma papilliferum. Morphologic, immunophenotypic, and molecular features of these neoplasms are largely similar to salivary gland tumours elsewhere, and therefore the exclusion of metastatic disease requires clinical and radiologic correlation. However, the differential diagnostic considerations are different in the lung. The distinction of salivary gland-type tumours from their histologic mimics is important for both prognostication and treatment decisions. Overall, salivary gland type-tumours tend to have a more favourable outcome than other pulmonary carcinomas, although high-grade variants exist for many of these tumour types. Recent advances in our understanding of the spectrum of salivary gland-type tumours reported in the lung and their diversity of molecular and immunohistochemical features have helped to refine the classification of these tumours and have highlighted a few differences between salivary gland-type tumours of the lung and those primary to other sites.

Targeted therapy for rare lung cancers: Status, challenges, and prospects

Lung cancer causes the most cancer-related deaths worldwide. In recent years, molecular and immunohistochemical techniques have rapidly developed, further inaugurating an era of personalized medicine for lung cancer. The rare subset of lung cancers accounts for approximately 10%, each displaying distinct clinical characteristics. Treatments for rare lung cancers are mainly based on evidence from common counterparts, which may lead to unsolid clinical benefits considering intertumoral heterogeneity. The increasing knowledge of molecular profiling of rare lung cancers has made targeting genetic alterations and immune checkpoints a powerful strategy. Additionally, cellular therapy has emerged as a promising way to target tumor cells. In this review, we first discuss the current status of targeted therapy and preclinical models for rare lung cancers, as well as provide mutational profiles by integrating the results of existing cohorts. Finally, we point out the challenges and future directions for developing targeted agents for rare lung cancer.

Pulmonary adenoid cystic carcinoma: molecular characteristics and literature review

BACKGROUND

Pulmonary adenoid cystic carcinoma (PACC) is an exceptionally rare salivary gland-type malignant neoplasm. Because of its clinical manifestations, imaging features are not different from other types of non-small cell lung cancer, which is a diagnostic challenge for most doctors.

CONCLUSIONS

A review of the literature shows that high amounts of immunohistochemical (IHC) markers, such as CK7, CD117, P63, SMA, CK5/6, and S-100 are helpful for PACC diagnosis. Surgical resection is the main treatment of PACC, but treatment options for advanced PACC patients are limited and the research of molecular targeted drugs is ongoing in advanced cases not eligible for surgery. Currently, research on PACC targeted therapy mainly focuses on the exploration of v-myb avian myeloblastosis virus oncogene homolog (MYB) and its downstream target genes. In addition, median tumor mutation burden and PD-1/PD-L1 were lower in PACC, which may indicate poor efficacy of immunotherapy in PACC patients. This review focuses on the pathologic features, molecular characteristics, diagnosis, treatment and prognosis of PACC to establish a comprehensive understanding of PACC.

Combined all-trans retinoic acid with low-dose apatinib in treatment of recurrent/metastatic head and neck adenoid cystic carcinoma: A single-center, secondary analysis of a phase II study

BACKGROUND

Treatment options are limited for recurrent/metastatic adenoid cystic carcinoma of the head and neck (R/M ACCHN). We aimed to evaluate the preliminary results of the efficacy and safety of all-trans retinoic acid (ATRA) combined with low-dose apatinib in patients with R/M ACCHN according to a secondary analysis of a phase II study.

METHODS

Patients from a phase II study (NCT02775370) who orally administered 500 milligram (mg) apatinib daily until treatment-related adverse events (AEs) intolerance or progression occurred were eligible for inclusion. Patients were further treated with combination therapy of ATRA (25 mg/m² /day) and apatinib (250 mg/day) between March 2019 and October 2021 until progression of disease (PD).

RESULTS

A total of 16 patients were included with nine (56.3%) males and aged 35-69 years old. All recruited patients previously received anti-angiogenic therapy then withdrew due to toxicities or progression occurred. The objective response rate (ORR) and disease control rate (DCR) were 18.8% and 100%, respectively. During a median follow-up of 23.9 months (range:17.8-31.7 months), 11 (68.8%) patients developed PD and one of them died in 20.9 months. The median of progression-free survival (PFS) was 16.3 months (95% CI: 7.2-25.4 months), and the 6-month, 12-month, and 24-month PFS rates were 100%, 81.3%, and 33.3%, respectively. The grade 3 adverse events were albuminuria (n = 2, 12.5%) and hand-foot syndrome (n = 1, 6.25%).

CONCLUSION

All-trans retinoic acid combined with low-dose apatinib might be a potential efficacy therapeutic option for patients with R/M ACCHN. This finding will be further confirmed by our registered ongoing trial, the APLUS study (NCT04433169).

Cell block-based RNA next generation sequencing for detection of gene fusions in lung adenocarcinoma: An institutional experience

OBJECTIVE

Targeted therapy is an important part of the treatment of lung adenocarcinoma. Tests for EGFR mutation, ALK, ROS1, RET and NTRK gene fusions are needed to make a treatment decision. These gene fusions are traditionally detected by fluorescence in situ hybridisation (FISH) or immunohistochemistry. In this study, we investigated whether gene fusions in pulmonary adenocarcinoma could be accurately detected by RNA next-generation sequencing (RNA-NGS) and whether cytology cell blocks could be used effectively for this test.

METHODS

Archived cytological specimens of lung adenocarcinoma submitted for RNA sequencing between 2019 and 2022 at Fox Chase Cancer Center were retrospectively retrieved. Hybrid capture-based targeted RNA next generation sequencing was used, which covers 507 fusion genes, including ALK, ROS1, RET and NTRKs, irrespective of their partner genes. DNA NGS, FISH and chromosomal microarray analysis were used to confirm the results of the RNA-NGS.

RESULTS

A total of 129 lung adenocarcinoma cytology specimens were submitted for molecular testing. Eight of 129 (6.2%) cases were excluded from RNA sequencing as their cell blocks contained inadequate numbers of tumour cells. One case (0.8%) failed to yield adequate RNA. The overall success rate was 93% (120/129). Ten of 120 (8.3%) cytology cases were positive for gene fusions, including 7 ALK, 2 ROS1 fusion genes, and 1 RET fusion gene. Twenty-two cell block cases were also tested for ALK fusion genes using FISH. However, 11 of 22 (50%) failed the testing due to inadequate material.

CONCLUSIONS

Cytology cell blocks can be used as the main source of material for molecular testing for lung cancer. Detection of gene fusions by RNA-based NGS on cell blocks is convenient and reliable in daily practice.

Adenoid Cystic Carcinoma of Salivary Glands: A Ten-Year Review and an Assessment of the Current Management, Surgery, Radiotherapy, and Chemotherapy

Adenoid cystic carcinoma (ACC) is a rare cancer that arises from the salivary glands and other sites in the body, such as the lung and breast. Although the tumor accounts for 10% of all salivary gland malignancies, it only accounts for 1% of head and neck malignancies. It can affect both major and minor salivary glands; here, it is called salivary gland adenoid cystic carcinoma or SACC, with a slight predilection to the latter, and commonly manifests between the 6_th and 7_th decades of life. The disease also shows a slight female predilection, with a reported female to male ratio of 3 : 2. Lesions of SACC are often insidious and slow-growing, and symptoms such as pain and altered sensation are frequently associated with advanced stages of the disease. Salivary adenoid cystic carcinoma is characterized by perineural invasion (PNI), a distinctive feature that potentially plays a significant role in the tumor's relapse and recurrence, which is approximately 50%. The disease is not prevalent, and its etiopathogenesis is poorly understood, although several genetic patterns and biomarkers have been linked to its initiation and/or progression. The discovery of these mutations and biomarkers has encouraged several clinical studies to use therapeutic agents to target the specific receptors on the cancer cells to potentially prevent further proliferation of the tumor cells and metastasis of the disease. Diagnosis of SACC is often challenging and frequently requires a combination of clinical examination, imaging, and histopathology. Management of SACC is primarily surgical excision, while radiotherapy has shown to be effective in improving local control in cases with microscopic residual disease. However, treatment of recurrent or metastatic tumors by radiotherapy with or without chemotherapy has so far shown limited success. The aim of this thesis is to provide an update of literature on SACC with a particular focus on the latest management approaches and future trends.

MYBL1 induces transcriptional activation of ANGPT2 to promote tumor angiogenesis and confer sorafenib resistance in human hepatocellular carcinoma

Angiogenesis is considered as an important process in tumor growth, metastasis of hepatocellular carcinoma (HCC) and associated with cancer progression, suggesting that an important research and development field of clinical molecular targeted drugs for HCC. However, the molecular mechanisms underlying tumor angiogenesis in HCC remains elusive. In the current study, we demonstrate that upregulation of AMYB proto-oncogene-like 1 (MYBL1) was associated with high endothelial vessel (EV) density and contributed to poor prognosis of HCC patient. Functionally, MYBL1 overexpressing enhanced the capacity of HCC cells to induce tube formation, migration of HUVECs, neovascularization in CAMs, finally, enhanced HCC cells metastasis, while silencing MYBL1 had the converse effect. Furthermore, HCC cells with high MYBL1 expression were more resistance to sorafenib treatment. We observed that CD31 staining was significantly increased in tumors formed by MYBL1-overexpressing cells but decreased in MYBL1-silenced tumors. Mechanistically, MYBL1 binds to the ANGPT2 promoter and transcriptionally upregulate ANGPT2 mRNA expression. Strikingly, treatment with monoclonal antibody against ANGPT2 significantly inhibited the growth of MYBL1-overexpressing tumors and efficiently impaired angiogenesis. Furthermore, the histone post-translational factors: protein arginine methyltransferase 5 (PRMT5), MEP50, and WDR5 were required for MYBL1-mediated ANGPT2 upregulation. Importantly, we confirmed the correlation between MYBL1 and ANGPT2 expression in a large cohort of clinical HCC samples and several published datasets in pancreatic cancer, esophageal carcinoma, stomach adenocarcinoma, and colon cancer. Our results demonstrate that MYBL1 upregulated the ANGPT2 expression, then induced angiogenesis and confer sorafenib resistance to HCC cells, and MYBL1 may represent a novel prognostic biomarker and therapeutic target for patients with HCC.

Metatypical Adenoid Cystic Carcinoma: A Variant Showing Prominent Squamous Differentiation With a Predilection for the Sinonasal Tract and Skull Base

Adenoid cystic carcinoma is a malignant salivary gland neoplasm, commonly involving the major and minor salivary glands. Adenoid cystic carcinoma arising in the skull base region is considerably less common and is characterized by aggressive clinical behavior, perineural invasion, and intracranial extension. Classically, these tumors are composed of ductal and myoepithelial cells, arranged as tubules and cribriform structures, as well as in a solid pattern when higher in grade. The distinctive molecular findings in this tumor are the gene fusions involving the MYB/MYBL1 and NFIB genes. Squamous differentiation, trabecular, and macrocystic growth patterns are exceedingly rare in these tumors and when present can cause significant diagnostic challenges. Squamous differentiation, in particular, is considered by many to be an exclusion criterion for adenoid cystic carcinoma outside of cases with high-grade transformation. In addition, a similar-appearing tumor with squamous differentiation, namely human papillomavirus-related multiphenotypic sinonasal carcinoma, has recently been defined, further complicating this differential diagnosis. Recently, we have come across 3 cases of adenoid cystic carcinomas involving the sinonasal tract and skull base having extensive interconnecting trabecular growth, macrocysts, and squamous differentiation, yet demonstrating the signature fusions involving MYB-NFIB and MYBL1-NFIB by RNA sequencing. In this article, we describe the clinical, histomorphologic, and imaging findings of these cases and propose the appellation "metatypical adenoid cystic carcinoma" for this uncommon variant morphology.

miR-1307 promotes hepatocarcinogenesis by CALR-OSTC-endoplasmic reticulum protein folding pathway

miR-1307 is highly expressed in liver cancer and inhibits methyltransferase protein8. Thereby, miR-1307 inhibits the expression of KDM3A and KDM3B and increases the methylation modification of histone H3 lysine 9, which enhances the expression of endoplasmic-reticulum-related gene CALR. Of note, miR-1307 weakens the binding ability of OSTC to CDK2, CDK4, CyclinD1, and cyclinE and enhances the binding ability of CALR to CDK2, CDK4, CyclinD1, and cyclinE, decreasing of p21WAF1/CIP1, GADD45, pRB, and p18, and decreasing of ppRB. Furthermore, miR-1307 increases the activity of H-Ras, PKM2, and PLK1. Strikingly, miR-1307 reduces the binding ability of OSTC to ATG4 and enhances the binding ability of CALR to ATG4. Therefore, miR-1307 reduces the occurrence of autophagy based on ATG4-LC3-ATG3-ATG7-ATG5-ATG16L1-ATG12-ATG9- Beclin1. In particular, miR-1307 enhances the expression of PAK2, PLK1, PRKAR2A, MYBL1, and Trim44 and inhibits the expression of Sash1 and Smad5 via autophagy. Our observations suggest that miR-1307 promotes hepatocarcinogenesis by CALR-OSTC-endoplasmic reticulum protein folding pathway.

CD105 expression is associated with invasive capacity in ovarian cancer and promotes invasiveness by inhibiting NDRG1 and regulating the epithelial-mesenchymal transition

This study investigates the association of CD105 (endoglin) with the invasiveness of paclitaxel-resistant ovarian cancer (OC) cells and explores the potential mechanism. A paclitaxel-resistant OC cell line OC3/TAX300, which expresses the stem cell marker CD105 and has a high invasive potential, was established in our previous study. After CD105 knockdown using CD105 siRNA, the invasiveness of the OC cells was decreased, and the chemo-resistance was reversed, but the CD105 overexpression was related to the poor survival of the primary OC patients. The differentially expressed genes were investigated in the OC cells after the CD105 knockdown. The results showed that, in the CD105-siRNA transfected cells, the expressions of some genes (such as KIAA0125, SSTR5-AS1, CDH18, MIAT, NDRG1, E-cadherin, DUSP1, MAL, MYC, and JAK3) were significantly upregulated, but the expressions of other genes (such as PRKAR2B, KLK10, DDX17, and lncRNA SNHG7) were markedly downregulated. Several genes, such as NDRG1 and E-cadherin, are known to be related to cancer metastasis and the epithelial-mesenchymal transition (EMT). A KEGG analysis found that 264 signaling pathways changed after the CD105 knockdown, of which 27 signaling pathways showed significant enrichment. Our results show that CD105 is related to the metastasis of OC and may promote the EMT of OC by inhibiting NDRG1 and E-cadherin. MYC, JAK3, and IKBKB mediate the CD105-induced metastasis of OC via the MAPK/PI3K/AKT and JAK/STAT signaling pathways in the OC cells. Therefore, inhibiting the CD105 expression may be useful for treating OC.

Salivary Gland-type Tumors of the Lung

CONTEXT.—

Salivary gland-type tumors (SGTs) of the lung represent a distinct group of lung neoplasms. Pulmonary SGTs often pose diagnostic challenges, especially in small biopsy and cytology samples because of limited sample volume and overlapping morphology among pulmonary SGTs, metastatic SGTs of head and neck origin, and other lung tumors.

OBJECTIVE.—

To identify the clinical characteristics, histomorphology, immunophenotypic features, and molecular alterations that are crucial for the diagnosis and differential diagnosis of pulmonary SGTs, especially in small biopsy and cytology specimens.

DATA SOURCES.—

Literature review and authors' personal practice experience.

CONCLUSIONS.—

An accurate diagnosis of pulmonary SGTs can be achieved by careful evaluation of clinical findings and histomorphology in conjunction with immunohistochemical studies and molecular analysis.

SMARCA2-NR4A3 is a novel fusion gene of extraskeletal myxoid chondrosarcoma identified by RNA next-generation sequencing

Extraskeletal myxoid chondrosarcoma (EMC) is a rare sarcoma of uncertain differentiation, characterized by recurrent chromosomal translocation involving NR4A3 (9q22.33) in more than 90% of cases. Five fusion partners for NR4A3 have been described including: EWSR1 (22q12.2), TAF15 (17q12), FUS (16p11.2), TCF12 (15q21), and TFG (3q12.2). This report describes a patient with an EMC at the dorsum of the right foot. The tumor showed a cord-like and reticular pattern in a background of myxoid matrix. The tumor cells demonstrated an epithelioid morphology with prominent nucleoli. The tumor cells were positive for synaptophysin, GFAP, with focal positivity for CD117, S100, Cam5.2, and NSE, and negative for AE1/3, desmin, and SMA. An RNA next-generation sequencing test showed a SMARCA2-NR4A3 gene fusion which has not been previously reported. The exon 3 of SMARCA2 was fused to exon 3 of NR4A3. This fusion was confirmed by NR4A3 break-apart FISH, although both SMARCA2 (9p24.3) and NR4A3 (9q22.33) are located on chromosome 9. The tumor cells showed retained expression of INI1 and SMARCA2 by immunohistochemistry.

Updates in the molecular pathology of non-small cell lung cancer

An understanding of the molecular pathology of non-small cell lung cancer (NSCLC) is important for pathologists as molecular characterization is now required for treatment decisions in advanced stage disease. While assessment for EGFR mutations, ALK and ROS1 fusions, and in some countries BRAF mutations, is now standard practice, other oncogenic mutations are also emerging that may impact routine clinical practice including alterations involving KRAS, NTRK, RET, MET and HER2. In addition, molecular pathology alterations of NSCLC are associated with responses to immune checkpoint therapy and are being increasingly investigated. Finally, specific molecular pathological alterations define some rarer subtypes of NSCLC such as salivary gland tumours, NUT carcinoma and SMARCA4-deficient undifferentiated tumour, and an understanding of the molecular pathology is important for their accurate diagnosis. In this review, the molecular pathology of NSCLC is discussed with a focus on clinically relevant molecular alterations.

BOC-PLAG1, a new fusion gene of pleomorphic adenoma: Identified in a fine-needle aspirate by RNA next-generation sequencing

Pleomorphic adenoma (PA) is the most common benign salivary gland tumor. Fine-needle aspiration (FNA) of PA exhibits variable combinations of bland ductal epithelial cells, myoepithelial cells, and characteristic magenta fibrillary stroma on Diff-Quik/Romanowsky stain. However, a cellular PA with scant chondromyxoid stroma can be a diagnostic challenge on FNA. Around 70% of PAs have a translocation involving PLAG1 or HMGA2. The presence of either PLAG1 or HMGA2 fusion gene can be used to diagnose PA since they have not been reported in other salivary gland tumors except for carcinoma ex PA. In this case report, we describe a case of cellular PA initially diagnosed on FNA as a "low grade salivary gland neoplasm, favor PA." RNA next-generation sequencing performed on the cell block showed a BOC-PLAG1 fusion gene. The presence of PLAG1 fusion gene in conjunction with cytomorphology supported a diagnosis of PA. The mass was surgically removed and proved to be a cellular PA with scattered foci of chondromyxoid and collagenous stroma. To our knowledge, this is the first reported PA bearing BOC-PLAG1. RNA next-generation sequencing performed on cytology specimens can be helpful in achieving a more specific diagnosis of salivary gland tumors.

MYB oncoproteins: emerging players and potential therapeutic targets in human cancer

MYB transcription factors are highly conserved from plants to vertebrates, indicating that their functions embrace fundamental mechanisms in the biology of cells and organisms. In humans, the MYB gene family is composed of three members: MYB, MYBL1 and MYBL2, encoding the transcription factors MYB, MYBL1, and MYBL2 (also known as c-MYB, A-MYB, and B-MYB), respectively. A truncated version of MYB, the prototype member of the MYB family, was originally identified as the product of the retroviral oncogene v-myb, which causes leukaemia in birds. This led to the hypothesis that aberrant activation of vertebrate MYB could also cause cancer. Despite more than three decades have elapsed since the isolation of v-myb, only recently investigators were able to detect MYB genes rearrangements and mutations, smoking gun evidence of the involvement of MYB family members in human cancer. In this review, we will highlight studies linking the activity of MYB family members to human malignancies and experimental therapeutic interventions tailored for MYB-expressing cancers.

Adenoid cystic carcinoma and chronic lymphocytic leukaemia: synchronous presentations in the lung

A 59-year-old male active smoker presented with a 6-month history of cough and breathlessness and was found to have a right upper lobe mass. Histology revealed this to be an adenoid cystic carcinoma (ACC) of the lung, while local lymph node dissection revealed a synchronous diagnosis of chronic lymphocytic leukaemia (CLL). The connection between CLL and solid organ malignancy is well documented, but the reporting of ACC in this context is novel. Mechanisms linking the two processes are revealed with the possibility of causality, and heightened vigilance for the development of primary lung tumours in CLL, and their management, is recommended.

Primary adenoid cystic carcinoma of the lung: A case report and literature review

Primary adenoid cystic carcinoma (ACC) of the lung is an unusual thoracic neoplasm with slow growing and low-grade malignancy. Usually, it is diagnosed at a higher clinical stage and is difficult to resect due to its central location. Herein, we report a 56-year-old man with hemoptysis associated with dyspnea and weight loss lasting for one month. Bronchial fibroscopy highlighted a budding nodular tumor in the left main bronchus. The patient underwent a left pneumonectomy with mediastinal lymphadenomectomy. Microscopic examination showed tumor cells infiltrating the bronchial wall and the cartilage and concluded to an ACC of the left bronchus. Ear, nose, and throat examination as well as cervico-facial magnetic resonance imaging were performed to search a primary salivary gland tumor and were returned without abnormalities. The tumor was classified as a primary ACC of the left bronchus without lymph node metastasis. To avoid their misdiagnosis, ACCs of the lung should be well known by the pathologist and surgeons. Their pathological features may be misleading and referring to a benign lesion, however, the presence of cribriform foci and infiltrative pattern are very suggestive. Although, indolent and slow growing tumor, long-term recurrences are quite frequent, especially in case of unclear surgical margin.

Problematic breast tumors reassessed in light of novel molecular data

Breast cancer is a vastly heterogeneous disease encompassing a panoply of special histological subtypes. Although rare breast tumors have largely not been investigated systematically in large scale genomics series, recent studies have shed light on the genetic underpinnings of special histologic subtypes of breast cancer. Genomic analyses of estrogen receptor-positive special histologic types of breast cancer have not resulted in the identification of novel pathognomonic genetic alterations in addition to the confirmation of the presence of CDH1 loss-of-function mutations in invasive lobular carcinomas. By contrast, the analyses of triple-negative breast cancers have demonstrated that low-grade triple-negative breast cancers categorically differ from the common forms of high-grade triple-negative disease biologically and phenotypically and are underpinned by specific fusion genes or hotspot mutations. A subset of low-grade triple-negative disease has been shown to harbor highly recurrent if not pathognomonic genetic alterations, such as ETV6-NTRK3 fusion gene in secretory carcinomas, the MYB-NFIB fusion gene, MYBL1 rearrangements or MYB gene amplification in adenoid cystic carcinomas, and HRAS Q61 hotspot mutations coupled with mutations in PI3K pathway genes in estrogen receptor-negative adenomyoepitheliomas. A subset of these pathognomonic genetic alterations (e.g., NTRK1/2/3 fusion genes) now constitute an FDA approved indication for the use of TRK inhibitors in the advanced/metastatic setting. These studies have also corroborated that salivary gland-like tumors of the breast, other than acinic cell carcinomas, harbor the repertoire of somatic genetic alterations detected in their salivary gland counterparts. Reassuringly, the systematic study of special histologic types of breast cancer utilizing state-of-the-art sequencing approaches, rather than rendering pathology obsolete, has actually strengthened the importance of breast cancer histologic typing and is providing additional ancillary markers for the diagnosis of these rare but fascinating entities.

Pulmonary Myoepithelial Tumors With Exuberant Reactive Pneumocytes: Proposed Reclassification of So-called Pneumocytic Adenomyoepithelioma

Pneumocytic adenomyoepithelioma (PAM) was first described in 2007 and was included in the 2015 World Health Organization Classification of lung tumors as a variant of epithelial-myoepithelial tumor. This rare pulmonary neoplasm was reported to show both myoepithelial and duct-like components, with the latter exhibiting pneumocytic differentiation with TTF-1 expression. We present an index case and 6 additional retrospectively identified cases of pulmonary tumors with prototypical features of PAM. However, with additional clinicoradiologic, histologic, immunohistochemical and cytogenetic data, we were able to reclassify them as myoepithelial neoplasms-both primary and metastatic-with entrapped exuberantly hyperplastic alveolar structures lined by TTF-1 pneumocytes. We reviewed the available literature related to PAM and myoepithelial tumors. Our cases suggest that the entity referred to as PAM represents interstitial growth of myoepithelial neoplasms enticing marked proliferation of entrapped pneumocytes rather than a distinct biphasic neoplasm with pneumocytic differentiation.

Clinical application of RNA sequencing in sarcoma diagnosis: An institutional experience

Accurate diagnoses of sarcoma are sometimes challenging on conventional histomorphology and immunophenotype. Many specific genetic aberrations including chromosomal translocations have been identified in various sarcomas, which can be detected by fluorescence in situ hybridization and polymerase chain reaction analysis. Next-generation sequencing-based RNA sequencing can screen multiple sarcoma-specific chromosome translocations/fusion genes in 1 test, which is especially useful for sarcoma without obvious differentiation. In this report, we utilized RNA sequencing on formalin-fixed paraffin-embedded (FFPE) specimens to investigate the possibility of diagnosing sarcomas by identifying disease-specific fusion genes. Targeted RNA sequencing was performed on 6 sarcoma cases. The expected genetic alterations (clear cell sarcoma/EWSR1-ATF1, Ewing sarcoma/EWSR1-FLI1, myxoid liposarcoma/DDIT3-FUS) in four cases were detected and confirmed by secondary tests. Interestingly, three SS18 fusion genes (SS18-SSX2B, SS18-SSX2, and SS18-SSX4) were identified in a synovial sarcoma case. A rare fusion gene (EWSR1-PATZ1) was identified in a morphologically challenging case; which enabled us to establish the diagnosis of low grade glioneural tumor. In conclusion, RNA sequencing on FFPE specimen is a reliable method in establishing the diagnosis of sarcoma in daily practice.