ABSTRACT
Therapy-resistant disease is a major cause of death in patients with acute lymphoblastic leukemia (ALL). Activation of the MYB oncogene is associated with ALL and leads to uncontrolled neoplastic cell proliferation and blocked differentiation. Here, we used RNA-seq to study the clinical significance of MYB expression and MYB alternative promoter (TSS2) usage in 133 pediatric ALLs. RNA-seq revealed that all cases analyzed overexpressed MYB and demonstrated MYB TSS2 activity. qPCR analyses confirmed the expression of the alternative MYB promoter also in seven ALL cell lines. Notably, high MYB TSS2 activity was significantly associated with relapse (p = 0.007). Moreover, cases with high MYB TSS2 usage showed evidence of therapy-resistant disease with increased expression of ABC multidrug resistance transporter genes (e.g., ABCA2, ABCB5, and ABCC10) and enzymes catalyzing drug degradation (e.g., CYP1A2, CYP2C9, and CYP3A5). Elevated MYB TSS2 activity was further associated with augmented KRAS signaling (p < 0.05) and decreased methylation of the conventional MYB promoter (p < 0.01). Taken together, our results suggest that MYB alternative promoter usage is a novel potential prognostic biomarker for relapse and therapy resistance in pediatric ALL.
Subject(s)
Precursor Cell Lymphoblastic Leukemia-Lymphoma , Humans , Child , Precursor Cell Lymphoblastic Leukemia-Lymphoma/genetics , Precursor Cell Lymphoblastic Leukemia-Lymphoma/drug therapy , Promoter Regions, Genetic , Chronic Disease , Signal Transduction , RecurrenceABSTRACT
BACKGROUND: A major challenge in the management of patients with oral leukoplakia is the difficulty to identify patients at high risk of developing oral squamous cell carcinoma. Our knowledge about genomic alterations in oral leukoplakia, and in particular those that progress to oral squamous cell carcinoma, is scarce and there are no useful biomarkers that can predict the risk of malignant transformation. METHODS: Using a novel, custom-made tissue microarray including 28 high-risk oral leukoplakias and the corresponding oral squamous cell carcinomas from 14 cases that progressed to cancer, we assayed copy number alterations involving the oral squamous cell carcinoma driver genes CDKN2A, CCND1, EGFR, and MYC by fluorescence in situ hybridization. The copy number alterationss were correlated with clinicopathological data from all patients. RESULTS: Copy number alterations were identified in 14/24 oral leukoplakias, analyzable for one or more of the oral squamous cell carcinoma driver genes. EGFR was the most frequently altered gene in oral leukoplakias with amplification/gain in 43.5% followed by loss of CDKN2A (26.1%), gains of CCND1 (26.1%), and MYC (8.3%). Losses of CDKN2A were more common in oral leukoplakias progressing to oral squamous cell carcinoma compared to those that did not. Copy number alterations were more common in oral squamous cell carcinomas than in oral leukoplakias. CONCLUSIONS: Our findings demonstrate that copy number alterations involving the oral squamous cell carcinoma drivers CDKN2A, EGFR, and CCND1 occur in oral leukoplakias and suggest a possible role for these genes in the development and/or progression of subsets of oral leukoplakias.
Subject(s)
Cyclin D1 , Cyclin-Dependent Kinase Inhibitor p16 , DNA Copy Number Variations , ErbB Receptors , Leukoplakia, Oral , Mouth Neoplasms , Squamous Cell Carcinoma of Head and Neck , Cyclin D1/genetics , Cyclin-Dependent Kinase Inhibitor p16/genetics , Disease Progression , ErbB Receptors/genetics , Humans , In Situ Hybridization, Fluorescence , Leukoplakia, Oral/genetics , Leukoplakia, Oral/pathology , Mouth Neoplasms/genetics , Mouth Neoplasms/pathology , Squamous Cell Carcinoma of Head and Neck/geneticsABSTRACT
The pleomorphic adenoma (PA), which is the most common salivary gland neoplasm, is a benign tumor characterized by recurrent chromosome rearrangements involving 8q12 and 12q14-15. We have previously shown that the PLAG1 and HMGA2 oncogenes are the targets of these rearrangements. Here, we have identified previously unrecognized subsets of PAs with ins(9;8)/t(8;9) (n = 5) and ins(9;12)/t(9;12) (n = 8) and breakpoints located in the vicinity of the PLAG1 and HMGA2 loci. RNA-sequencing and reverse transcriptase (RT)-PCR analyses of a case with an ins(9;8) revealed a novel NFIB-PLAG1 fusion in which NFIB exon 4 is linked to PLAG1 exon 3. In contrast to the developmentally regulated PLAG1 gene, NFIB was highly expressed in normal salivary gland, indicating that PLAG1 in this case, as in other variant fusions, is activated by promoter swapping. RT-PCR analysis of three PAs with t(9;12) revealed two tumors with chimeric transcripts consisting of HMGA2 exon 4 linked to NFIB exons 9 or 3 and one case with a fusion linking HMGA2 exon 3 to NFIB exon 9. The NFIB fusion events resulted in potent activation of PLAG1 and HMGA2. Analysis of the chromatin landscape surrounding NFIB revealed several super-enhancers in the 5'- and 3'-parts of the NFIB locus and its flanking sequences. These findings indicate that PLAG1 and HMGA2, similar to MYB in adenoid cystic carcinoma, may be activated by enhancer-hijacking events, in which super-enhancers in NFIB are translocated upstream of PLAG1 or downstream of HMGA2. Our results further emphasize the role of NFIB as a fusion partner to multiple oncogenes in histopathologically different types of salivary gland tumors.
Subject(s)
DNA-Binding Proteins/genetics , Gene Expression Regulation, Neoplastic , HMGA2 Protein/genetics , NFI Transcription Factors/genetics , Oncogene Proteins, Fusion/genetics , Salivary Gland Neoplasms/genetics , Chromatin/chemistry , Chromatin/genetics , DNA-Binding Proteins/metabolism , Enhancer Elements, Genetic , HMGA2 Protein/metabolism , Humans , NFI Transcription Factors/metabolism , Oncogene Proteins, Fusion/metabolism , Salivary Glands/metabolism , Transcriptional ActivationABSTRACT
Adenosquamous carcinoma of the pancreas (ASCAP) is characterized by conventional pancreatic ductal adenocarcinoma (PDAC) and squamous carcinoma components with at least 30% of the tumour showing squamous differentiation. To get further insight into the histogenesis of these lesions, we analysed the cellular organization of ASCAP compared to PDACs. Using Immunohistochemistry and triple immunofluorescence labelling studies for keratins, p63, p40, MUC1, MUC2, MUC5AC, Ki67, and EGFR we demonstrate that many ASCAPs contain a transitional zone between the K8/18-positive adenocarcinomatous component and the p63+ /p40+ /K5/K14+ squamous component initiated by the expression of p63 in K8/18+ adenocarcinomatous cells and the appearance of basally located p63+ K5/14+ cells. p63+ K5/14+ cells give rise to fully developed squamous differentiation. Notably, 25% of conventional PDACs without histologically recognizable squamous component contain foci of p63+ p40+ and K5/14+ cells similar to the transitional zone. Our data provide evidence that the squamous carcinoma components of ASCAPs originate from pre-existing PDAC via transdifferentiation of keratin K8/18-positive glandular cells to p63-, p40-, and keratin K5/14-positive squamous carcinoma cells supporting the squamous metaplasia hypothesis. Thus our findings provide new evidence about the cellular process behind squamous differentiation in ASCAPs.
Subject(s)
Carcinoma, Adenosquamous/pathology , Carcinoma, Squamous Cell/pathology , Pancreatic Neoplasms/pathology , Aged , Aged, 80 and over , Carcinoma, Adenosquamous/metabolism , Carcinoma, Squamous Cell/metabolism , Cell Differentiation , Female , Humans , Keratins/metabolism , Male , Middle Aged , Pancreatic Neoplasms/metabolismABSTRACT
Craniosynostosis (CS), the premature closure of one or more cranial sutures, occurs both as part of a syndrome or in isolation (nonsyndromic form). Here, we have studied the prevalence and spectrum of genetic alterations associated with coronal suture closure in 100 Scandinavian patients treated at a single craniofacial unit. All patients were phenotypically assessed and analyzed with a custom-designed 63 gene NGS-panel. Most cases (78%) were syndromic forms of CS. Pathogenic and likely pathogenic variants explaining the phenotype were found in 80% of the families with syndromic CS and in 14% of those with nonsyndromic CS. Sixty-five percent of the families had mutations in the CS core genes FGFR2, TWIST1, FGFR3, TCF12, EFNB1, FGFR1, and POR. Five novel pathogenic/likely pathogenic variants in TWIST1, TCF12, and EFNB1 were identified. We also found novel variants in SPECC1L, IGF1R, and CYP26B1 with a possible modulator phenotypic effect. Our findings demonstrate that NGS targeted sequencing is a powerful tool to detect pathogenic mutations in patients with coronal CS and further emphasize the importance of thorough assessment of the patient's phenotype for reliable interpretation of the molecular findings. This is particularly important in patients with complex phenotypes and rare forms of CS.
Subject(s)
Craniofacial Abnormalities/genetics , Craniosynostoses/genetics , Genetic Predisposition to Disease , High-Throughput Nucleotide Sequencing , Basic Helix-Loop-Helix Transcription Factors/genetics , Cranial Sutures/pathology , Craniofacial Abnormalities/epidemiology , Craniofacial Abnormalities/pathology , Craniosynostoses/epidemiology , Craniosynostoses/pathology , Cytochrome P-450 Enzyme System/genetics , Ephrin-B1/genetics , Female , Humans , Male , Mutation/genetics , Nuclear Proteins/genetics , Phenotype , Receptor, Fibroblast Growth Factor, Type 1/genetics , Receptor, Fibroblast Growth Factor, Type 2/genetics , Receptor, Fibroblast Growth Factor, Type 3/genetics , Sweden/epidemiology , Twist-Related Protein 1/geneticsABSTRACT
Cutaneous cylindroma is an adnexal tumour with apocrine differentiation. A predisposition to multiple cylindromas is seen in patients with Brooke-Spiegler syndrome, who carry germline mutations in the tumour suppressor gene CYLD. Previous studies of inherited cylindromas have highlighted the frequent presence of bi-allelic truncating CYLD mutations as a recurrent driver mutation. We have previously shown that sporadic cylindromas express either MYB-NFIB fusion transcripts or show evidence of MYB activation in the absence of such fusions. Here, we investigated inherited cylindromas from several families with germline CYLD mutations for the presence of MYB activation. Strikingly, none of the inherited CYLD-defective (n = 23) tumours expressed MYB-NFIB fusion transcripts. However, MYB expression was increased in the majority of tumours (69%) and global gene expression analysis revealed that well-established MYB target genes were up-regulated in CYLD-defective tumours. Moreover, knock-down of MYB expression caused a significant reduction in cylindroma cell proliferation, suggesting that MYB is also a key player and oncogenic driver in inherited cylindromas. Taken together, our findings suggest molecular heterogeneity in the pathogenesis of sporadic and inherited cutaneous cylindromas, with convergence on MYB activation. © 2016 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.
Subject(s)
Germ-Line Mutation , Neoplastic Syndromes, Hereditary/genetics , Oncogene Proteins, Fusion/genetics , Skin Neoplasms/genetics , Tumor Suppressor Proteins/genetics , Adult , Aged , Aged, 80 and over , Cell Proliferation , Deubiquitinating Enzyme CYLD , Female , Gene Expression Profiling , Genotype , Humans , In Situ Hybridization, Fluorescence , Male , Middle Aged , Neoplastic Syndromes, Hereditary/metabolism , Neoplastic Syndromes, Hereditary/pathology , Oligonucleotide Array Sequence Analysis , Oncogene Proteins, Fusion/metabolism , Phenotype , Sequence Analysis, DNA , Skin Neoplasms/metabolism , Skin Neoplasms/pathology , Tumor Suppressor Proteins/metabolismABSTRACT
PURPOSE: To study genetic alterations in lacrimal gland pleomorphic adenoma (PA) and carcinoma ex pleomorphic adenoma (Ca-ex-PA) with focus on copy number changes and expression patterns of the translocation target genes PLAG1, HMGA2, and CRTC1-MAML2 in relation to clinical data. DESIGN: Experimental study. PARTICIPANTS: A total of 36 tumors from 32 patients with lacrimal gland PA or Ca-ex-PA were included in the study. METHODS: Genome wide, high-resolution array-based comparative genomic hybridization (arrayCGH) and immunohistochemistry were used to study the genomic profiles and expression patterns of the translocation targets PLAG1, HMGA2, and CRTC1-MAML2. MAIN OUTCOME MEASURES: Copy number alterations (gains/losses) and protein expression of PLAG1, HMGA2, and CRTC1-MAML2. RESULTS: Genome-wide arrayCGH analysis revealed normal genomic profiles in 10 of 17 PA samples. The average number of genomic imbalances per tumor was 3.25 (range, 1-7) in primary and recurrent PAs with alterations compared with 7.7 (range, 4-12) in Ca-ex-PAs. Five recurrent copy number alterations were identified in PAs, including losses of 1pter-p31.3, 6q22.1-q24.3, 8q24.22-q24.3, and 13q21.31-q21.33, and gain of 9p23-p22.3. Gain of 9p23-p22.3 also was seen in a Ca-ex-PA. In Ca-ex-PA, gain of 22q12.3-qter was the only recurrent alteration. Detailed analysis of the array data identified NFIB and PDGFB as the 2 major candidate target oncogenes that may be activated as a result of copy number gains involving 9p and 22q. Both genes have been implicated in the pathogenesis of PA and other types of salivary gland tumors. Immunohistochemical analysis revealed frequent overexpression of the translocation target gene PLAG1 in PAs and in 1 Ca-ex-PA. In contrast, overexpression of HMGA2 was observed in only a small subset of PAs. The CRTC1-MAML2 fusion oncoprotein was overexpressed in 2 mucoepidermoid Ca-ex-PAs. CONCLUSIONS: Lacrimal and salivary gland PAs and Ca-ex-PAs have similar genomic profiles and frequently overexpress the PLAG1 oncoprotein. Copy number gains involving 9p23-p22.3 (NFIB) and 22q12-qter (PDGFB) may be of importance for disease progression in a subset of lacrimal gland PAs.
Subject(s)
Adenocarcinoma/genetics , Adenoma, Pleomorphic/genetics , Eye Neoplasms/genetics , Gene Expression Regulation, Neoplastic/genetics , Gene Fusion , Lacrimal Apparatus Diseases/genetics , Adenocarcinoma/metabolism , Adenocarcinoma/pathology , Adenoma, Pleomorphic/metabolism , Adenoma, Pleomorphic/pathology , Adolescent , Adult , Aged , Aged, 80 and over , Comparative Genomic Hybridization , DNA Copy Number Variations , DNA-Binding Proteins/genetics , DNA-Binding Proteins/metabolism , Eye Neoplasms/metabolism , Eye Neoplasms/pathology , Female , HMGA2 Protein/genetics , HMGA2 Protein/metabolism , Humans , Immunohistochemistry , Lacrimal Apparatus Diseases/metabolism , Lacrimal Apparatus Diseases/pathology , Male , Middle Aged , Nuclear Proteins/genetics , Nuclear Proteins/metabolism , Oncogene Proteins, Fusion , Trans-Activators , Transcription Factors/genetics , Transcription Factors/metabolism , Translocation, GeneticABSTRACT
OBJECTIVE: Adenoid cystic carcinoma (ACC) is a head and neck cancer with a poor long-term prognosis that shows frequent local recurrences and distant metastases. The tumors are characterized by MYB oncogene activation and are notoriously unresponsive to systemic therapies. The biological underpinnings behind therapy resistance of disseminated ACC are largely unknown. Here, we have studied the molecular and clinical significance of MYB alternative promoter (TSS2) usage in ACC metastases. MATERIALS AND METHODS: MYB TSS2 activity was investigated in primary tumors and metastases from 26 ACC patients using RNA-sequencing and quantitative real-time PCR analysis. Differences in global gene expression between MYB TSS2 high and low cases were studied, and pathway analyses were performed. RESULTS: MYB TSS2 activity was significantly higher in ACC metastases than in primary tumors (median activity 15.1 vs 3.0, P = 0.0003). MYB TSS2 high ACC metastases showed a specific gene expression signature, including increased expression of multi-drug resistance genes and canonical MYB target genes, and suppression of the p53 and NOTCH pathways. CONCLUSIONS: Collectively, our findings indicate that elevated MYB TSS2 activity is associated with metastases, potential drug resistance, and augmented MYB-driven gene expression in ACC. Our study advocates the need for new therapies that specifically target MYB and drug resistance mechanisms in disseminated ACC.
Subject(s)
Carcinoma, Adenoid Cystic , Head and Neck Neoplasms , Salivary Gland Neoplasms , Humans , Carcinoma, Adenoid Cystic/pathology , Genes, myb/genetics , Head and Neck Neoplasms/genetics , Salivary Gland Neoplasms/genetics , Salivary Gland Neoplasms/pathology , TranscriptomeABSTRACT
PURPOSE: To investigate genetic alterations in lacrimal gland adenoid cystic carcinomas (ACCs) with emphasis on the MYB-NFIB fusion oncogene and its downstream targets, MYB rearrangements, and copy number alterations in relation to clinical data and survival. DESIGN: Experimental study. PARTICIPANTS AND CONTROLS: Fourteen patients with primary lacrimal gland ACC were included. As a control, we also studied the expression of MYB-NFIB in 19 non-ACC lacrimal gland tumors. METHODS: The expression and identity of MYB-NFIB fusion transcripts were studied using reverse transcriptase polymerase chain reaction (RT-PCR) and nucleotide sequence analyses. Quantitative polymerase chain reaction (PCR) and immunohistochemistry were used to evaluate the expression of MYB/MYB-NFIB target genes. High-resolution array-based comparative genomic hybridization (arrayCGH) and fluorescence in situ hybridization were used to study copy number alterations and MYB rearrangements. MAIN OUTCOME MEASURES: mRNA or protein expression of MYB-NFIB, MYB, and its down stream targets; copy number alterations; and genomic rearrangements. RESULTS: The median age of the patients was 43 years (equal gender distribution), and the median time of survival was 8.6 years. The MYB-NFIB fusion was expressed in 7 of 14 ACCs. In contrast, all non-ACC tumors were fusion-negative. All 13 ACCs tested stained positive for the MYB protein, and for the MYB targets KIT and BCL2, 12 were positive for MYC and CCNE1, and 9 were positive for CCNB1. Rearrangements of MYB were detected in 8 of 13 cases, including 2 cases with gain of an apparently intact MYB gene. The arrayCGH analysis revealed recurrent copy number alterations with losses involving 6q23-q27, 12q12-q14.1, and 17p13.3-p12, and gains involving 19q12, 19q13.31-qter, 8q24.13-q24.21, 11q12.3-q14.1, and 6q23.3. Neither MYB-NFIB fusion nor any copy number alteration correlated with survival. CONCLUSIONS: Lacrimal gland ACCs are frequently positive for the MYB-NFIB fusion, overexpress MYB and its downstream targets, and have genomic profiles characterized by losses involving 6q, 12q, and 17p, and gains involving 19q, 8q, and 11q. Our findings show that lacrimal gland ACCs are genetically and clinically similar to their salivary gland counterparts and that MYB-NFIB is a clinically useful diagnostic biomarker for ACC. Our data also suggest that MYB and its downstream targets are potential therapeutic targets for these tumors. FINANCIAL DISCLOSURE(S): The author(s) have no proprietary or commercial interest in any materials discussed in this article.
Subject(s)
Carcinoma, Adenoid Cystic/genetics , Eye Neoplasms/genetics , Genes, myb/genetics , Lacrimal Apparatus Diseases/genetics , Adult , Aged , Carcinoma, Adenoid Cystic/metabolism , Eye Neoplasms/metabolism , Female , Humans , Immunohistochemistry , Lacrimal Apparatus Diseases/metabolism , Male , Middle Aged , Oncogene Proteins, Fusion/metabolism , Proto-Oncogene Proteins c-myb/metabolism , Reverse Transcriptase Polymerase Chain Reaction , Sequence Analysis, DNAABSTRACT
T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive hematologic malignancy with poor prognosis. The MYB oncogene encodes a master transcription factor that is activated in the majority of human T-ALLs. In the present study, we have performed a large-scale screening with small-molecule drugs to find clinically useful inhibitors of MYB gene expression in T-ALL. We identified several pharmacological agents that potentially could be used to treat MYB-driven malignancies. In particular, treatment with the synthetic oleanane triterpenoids (OTs) bardoxolone methyl and omaveloxolone decreased MYB gene activity and expression of MYB downstream target genes in T-ALL cells with constitutive MYB gene activation. Notably, treatment with bardoxolone methyl and omaveloxolone led to a dose-dependent reduction in cell viability and induction of apoptosis at low nanomolar concentrations. In contrast, normal bone marrow-derived cells were unaffected at these concentrations. Bardoxolone methyl and omaveloxolone treatment downregulated the expression of DNA repair genes and sensitized T-ALL cells to doxorubicin, a drug that is part of the standard therapy of T-ALL. OT treatment may thus potentiate DNA-damaging chemotherapy through attenuation of DNA repair. Taken together, our results indicate that synthetic OTs may be useful in the treatment of T-ALL and potentially also in other MYB-driven malignancies.
ABSTRACT
Background: This study assessed the diagnostic yield of high-throughput sequencing methods in a cohort of craniosynostosis (CS) patients not presenting causal variants identified through previous targeted analysis. Methods: Whole-genome or whole-exome sequencing (WGS/WES) was performed in a cohort of 59 patients (from 57 families) assessed by retrospective phenotyping as having syndromic or nonsyndromic CS. Results: A syndromic form was identified in 51% of the unrelated cases. A genetic cause was identified in 38% of syndromic cases, with novel variants detected in FGFR2 (a rare Alu insertion), TWIST1, TCF12, KIAA0586, HDAC9, FOXP1, and NSD2. Additionally, we report two patients with rare recurrent variants in KAT6A and YY1 as well as two patients with structural genomic aberrations: one with a 22q13 duplication and one with a complex rearrangement involving chromosome 2 (2p25 duplication including SOX11 and deletion of 2q22). Moreover, we identified potentially relevant variants in 87% of the remaining families with no previously detected causal variants, including novel variants in ADAMTSL4, ASH1L, ATRX, C2CD3, CHD5, ERF, H4C5, IFT122, IFT140, KDM6B, KMT2D, LTBP1, MAP3K7, NOTCH2, NSD1, SOS1, SPRY1, POLR2A, PRRX1, RECQL4, TAB2, TAOK1, TET3, TGFBR1, TCF20, and ZBTB20. Conclusion: These results confirm WGS/WES as a powerful diagnostic tool capable of either targeted in silico or broad genomic analysis depending on phenotypic presentation (e.g., classical or unusual forms of syndromic CS).
ABSTRACT
Here, we have studied the prevalence and spectrum of genetic alterations in syndromic forms of sagittal and pansynostosis. Eighteen patients with sagittal synostosis (isolated or combined with other synostoses, except coronal) or pansynostosis were phenotypically assessed by retrospective analysis of medical records, three-dimensional computed tomography skull reconstructions, and registered photos. Patient DNAs were analyzed using a targeted next-generation sequencing (NGS) panel including 63 craniosynostosis (CS) related genes. Pathogenic and likely pathogenic variants were found in 72% of the cases, mainly affecting FGFR2, TWIST1, IL11RA, and SKI. Two patients that were negative at NGS screening - one with a supernumerary marker chromosome with duplication of 15q25.2q26.3 and one with a pathogenic PHEX variant - were identified using microarray and single gene analysis, respectively. The overall diagnostic rate in the cohort was thus 83%. We identified two novel likely pathogenic variants in FGFR2 (NM_022970.3: c.811_812delGGinsCC, p.Gly271Pro) and TWIST1 (NM_000474.3: c.476T > A, p.Leu159His), and a novel variant of unclear phenotypic significance in RUNX2 (NM_001024630.3: c.340G > A, p.Val114Ile) which could suggest a modulatory effect. Notably, we also identified three new patients with pansynostosis and a Crouzon-like phenotype with IL11RA mutation. Targeted NGS using a broad panel of CS-related genes is a simple and powerful tool for detecting pathogenic mutations in patients with syndromic forms of CS and multiple suture involvement, in particular pansynostosis. Our results provide additional evidence of an association between pansynostosis and IL11RA, an emerging core gene for autosomal recessive CS.
Subject(s)
Craniosynostoses , Craniosynostoses/diagnosis , Craniosynostoses/genetics , Craniosynostoses/pathology , High-Throughput Nucleotide Sequencing , Humans , Interleukin-11 Receptor alpha Subunit/genetics , Mutation , Phenotype , Retrospective StudiesABSTRACT
Salivary gland tumors are a heterogeneous group of tumors originating from the major and minor salivary glands. The pleomorphic adenoma (PA), which is the most common subtype, is a benign lesion showing a remarkable morphologic diversity and that, upon recurrence or malignant transformation, can cause significant clinical problems. Cytogenetic studies of >500 PAs have revealed a complex and recurrent pattern of chromosome rearrangements. In this review, we discuss the specificity and frequency of these rearrangements and their molecular/clinical consequences. The genomic hallmark of PA is translocations with breakpoints in 8q12 and 12q13-15 resulting in gene fusions involving the transcription factor genes PLAG1 and HMGA2. Until recently, the association between these two oncogenic drivers was obscure. Studies of the Silver−Russel syndrome, a growth retardation condition infrequently caused by mutations in IGF2/HMGA2/PLAG1, have provided new clues to the understanding of the molecular pathogenesis of PA. These studies have demonstrated that HMGA2 is an upstream regulator of PLAG1 and that HMGA2 regulates the expression of IGF2 via PLAG1. This provides a novel explanation for the 8q12/12q13-15 aberrations in PA and identifies IGF2 as a major oncogenic driver and therapeutic target in PA. These studies have important diagnostic and therapeutic implications for patients with PA.
ABSTRACT
BACKGROUND/AIM: Polymorphous adenocarcinoma (PAC) is a low-grade salivary gland malignancy in contrast to variants with papillary (PAP) or cribriform (CASG) architecture and confers the second most common malignancy of minor salivary glands. Our study aimed to identify prognostic factors and to evaluate histomorphological and molecular diagnostic criteria of PACs. PATIENTS AND METHODS: A series of 155 PACs, including 10 PAPs and 12 CASGs from the population-based Cancer Registry of North Rhine-Westphalia (LKR-NRW) and the Hamburg Salivary Gland Reference Centre (HRC) were analyzed. RESULTS: One fifth of the tumors were located in the major salivary glands and PACS/CASGS invariably lacked p40 expression. Fifty-two percent of PACs showed a PRKD1 E710D mutation. Ordinary PACs had a disease-specific 10-year survival probability of 97% compared to 90% when combining PAPs and CASGs. T-stage at diagnosis was a prognostic factor with 98% for stages T1/T2 versus 75% for T3/T4. CONCLUSION: Diagnostic algorithms for the PAC/CASG spectrum of tumors need to be improved and should include molecular markers.
Subject(s)
Adenocarcinoma, Papillary , Adenocarcinoma , Biomarkers, Tumor , Salivary Gland Neoplasms , Adenocarcinoma/chemistry , Adenocarcinoma/genetics , Adenocarcinoma/mortality , Adenocarcinoma/pathology , Adenocarcinoma, Papillary/chemistry , Adenocarcinoma, Papillary/genetics , Adenocarcinoma, Papillary/mortality , Adenocarcinoma, Papillary/pathology , Adolescent , Adult , Aged , Aged, 80 and over , Biomarkers, Tumor/analysis , Biomarkers, Tumor/genetics , Child , Female , Germany , Humans , Male , Middle Aged , Mutation , Neoplasm Staging , Registries , Salivary Gland Neoplasms/chemistry , Salivary Gland Neoplasms/genetics , Salivary Gland Neoplasms/mortality , Salivary Gland Neoplasms/pathology , Sex Factors , Time Factors , Tumor Burden , Young AdultABSTRACT
Recent studies have shown that the recurrent t(6;9)(q22-23;p23-24) translocation in adenoid cystic carcinoma results in a novel fusion of the MYB proto-oncogene with the transcription factor gene NFIB. To determine the frequency of this finding, we used RT-PCR assays of the MYB and MYB-NFIB fusion transcripts, and immunohistochemistry for the MYB protein, to study adenoid cystic carcinomas and other epithelial tumors of the salivary glands, and head and neck region. MYB-NFIB fusion transcript was detected in 25 of 29 (86%) frozen adenoid cystic carcinoma tumor samples, and in 14 of 32 (44%) formalin-fixed paraffin-embedded adenoid cystic carcinoma tumor specimens. In contrast, the MYB-NFIB fusion was not expressed in non-adenoid cystic carcinoma neoplasms of the head and neck, confirming the high specificity of the MYB-NFIB fusion. Adenoid cystic carcinomas from various anatomic sites, including salivary gland, sinonasal cavity, tracheobronchial tree, larynx, breast, and vulva were repeatedly fusion-positive, indicating that adenoid cystic carcinomas located in different anatomic sites not only have important morphologic features in common, but also probably evolve through activation of the same molecular pathways. Studies of the expression of MYB revealed that 89% of the tumors, including both fusion-positive and fusion-negative cases, overexpressed MYB RNA. Similarly, 82% of adenoid cystic carcinomas stained positive for MYB protein, compared with 14% of non-adenoid cystic carcinoma neoplasms, indicating that MYB immunostaining may be useful for the diagnosis of adenoid cystic carcinoma, but that neoplasms sometimes in the differential diagnosis are also labeled. The latter are, however, fusion-negative. In summary, our studies show that MYB activation through gene fusion or other mechanisms is a major oncogenic event in adenoid cystic carcinoma occurring at various anatomic sites. In addition to being a diagnostically useful biomarker for adenoid cystic carcinoma, MYB and its downstream effectors are also novel potential therapeutic targets.
Subject(s)
Carcinoma, Adenoid Cystic/genetics , Oncogene Proteins v-myb/biosynthesis , Oncogene Proteins, Fusion/genetics , Salivary Gland Neoplasms/genetics , Adult , Aged , Biomarkers, Tumor/analysis , Biomarkers, Tumor/genetics , Carcinoma, Adenoid Cystic/metabolism , Female , Genes, myb , Humans , Immunohistochemistry , Male , Middle Aged , Oncogene Proteins v-myb/genetics , Proto-Oncogene Mas , Real-Time Polymerase Chain Reaction , Reverse Transcriptase Polymerase Chain Reaction , Salivary Gland Neoplasms/metabolism , Young AdultABSTRACT
Mucoepidermoid carcinoma (MEC) is the most common carcinoma of the salivary glands. Here, we have used two large patient cohorts with MECs comprising 551 tumors to study clinical, histological, and molecular predictors of survival. One cohort (n = 167), with known CRCT1/3-MAML2 fusion status, was derived from the Hamburg Reference Centre (HRC; graded with the AFIP and Brandwein systems) and the other (n = 384) was derived from the population-based Cancer Registry of North Rhine-Westphalia (LKR-NRW; graded with the AFIP system). The reliability of both the AFIP and Brandwein grading systems was excellent (n = 155). The weighted kappa for inter-rater agreement was 0.81 (95% CI 0.65-0.97) and 0.83 (95% CI 0.71-0.96) for the AFIP and Brandwein systems, respectively. The 5-year relative survival was 79.7% (95% CI 73.2-86.2%). Although the Brandwein system resulted in a higher rate of G3-MECs, survival in G3-tumors (AFIP or Brandwein grading) was markedly worse than in G1/G2-tumors. Survival in > T2 tumors was markedly worse than in those with lower T-stage. Also, fusion-negative MECs had a worse 5-year progression-free survival. The frequency of fusion-positive MECs in the HRC cohort was 78.4%, of which the majority (86.7%) was G1/G2-tumors. In conclusion, the AFIP and Brandwein systems are useful in estimating prognosis and to guide therapy for G3-MECs. However, their significance regarding young age (≤ 30 years) and location-dependent heterogeneity of in particular G2-tumors is more questionable. We conclude that CRTC1/3-MAML2 testing is a useful adjunct to histologic scoring of MECs and for pinpointing tumors with poor prognosis with higher precision, thus avoiding overtreatment.
Subject(s)
Biomarkers, Tumor/genetics , Carcinoma, Mucoepidermoid/genetics , Carcinoma, Mucoepidermoid/pathology , Gene Fusion , Salivary Gland Neoplasms/genetics , Salivary Gland Neoplasms/pathology , Trans-Activators/genetics , Transcription Factors/genetics , Adolescent , Adult , Carcinoma, Mucoepidermoid/mortality , Carcinoma, Mucoepidermoid/therapy , Female , Germany , Humans , Male , Middle Aged , Neoplasm Grading , Neoplasm Staging , Predictive Value of Tests , Progression-Free Survival , Registries , Salivary Gland Neoplasms/mortality , Salivary Gland Neoplasms/therapy , Time Factors , Young AdultABSTRACT
Recently, the concept of cancer stem cells and their expression of embryonic stem cell markers has gained considerable experimental support. In this study, we examined the expression of one such marker, the high-mobility group AT-hook 2 gene (HMGA2) mRNA, in 53 formalin-fixed, paraffin-embedded mucoepidermoid carcinomas (MEC) and four normal parotid tissues using quantitative real-time RT-PCR (qPCR). MECs are often characterized by the fusion gene CRTC1-MAML2, the detection of which is an important tool for the diagnosis and prognosis of MEC. For detection of the CRTC1-MAML2 fusion transcript, we performed RT-PCR. The mean expression level of HMGA2 was higher in fusion negative (302.8 +/- 124.4; n = 14) than in positive tumors (67.3 +/- 13.1; n = 39). Furthermore, the fusion-negative tumors were often high-grade tumors and the HMGA2 expression level rose with the tumor grade (low: 43.7 +/- 11.0, intermediate: 126.2 +/- 28.3, and high: 271.2 +/- 126.5). A significant difference was found in the HMGA2 expression levels between the different grading groups (one-way ANOVA, P = 0.04) and among the fusion-negative and -positive tumors (t-test, P = 0.05), indicating that the expression level of HMGA2 was closely linked to grading, the presence/absence of the CRTC1-MAML2 fusion, and the tumor behavior of MECs. These findings offer further evidence for the theory that the MEC group comprises two subgroups: one group with the CRTC1-MAML2 fusion, which is a group with a moderate aggressiveness and prognosis, and the other group lacking that fusion corresponding to an increased stemness, and thus, higher aggressiveness and worse prognosis.
Subject(s)
Carcinoma, Mucoepidermoid/genetics , DNA-Binding Proteins/genetics , HMGA2 Protein/genetics , Nuclear Proteins/genetics , Oncogene Proteins, Fusion/genetics , Transcription Factors/genetics , Adolescent , Adult , Aged , Aged, 80 and over , Analysis of Variance , Carcinoma, Mucoepidermoid/metabolism , Carcinoma, Mucoepidermoid/pathology , DNA-Binding Proteins/biosynthesis , Female , Gene Expression Profiling/methods , HMGA2 Protein/biosynthesis , Humans , Male , Middle Aged , Nuclear Proteins/biosynthesis , Oncogene Proteins, Fusion/biosynthesis , Parotid Gland/metabolism , Polymerase Chain Reaction , Trans-Activators , Transcription Factors/biosynthesis , Young AdultSubject(s)
Maxillary Sinus Neoplasms/genetics , Maxillary Sinus Neoplasms/pathology , Oncogene Proteins, Fusion/genetics , Skin Neoplasms/genetics , Skin Neoplasms/secondary , Aged, 80 and over , Base Sequence , Biomarkers, Tumor/genetics , Carcinoma, Adenoid Cystic/genetics , Carcinoma, Adenoid Cystic/pathology , Carcinoma, Adenoid Cystic/secondary , Chromosome Aberrations , Comparative Genomic Hybridization , DNA Mutational Analysis , DNA, Neoplasm/genetics , Female , Gene Expression Profiling , Humans , Skin Neoplasms/pathologyABSTRACT
The aim of this study was to determine genetic alterations in mucoepidermoid carcinomas of the salivary gland in association with clinical and histopathological parameters. Nineteen formalin-fixed, paraffin-embedded tumors were analysed by using comparative genomic hybridization (CGH), fluorescence in situ hybridization (FISH) on interphase nuclei and reverse transcriptase-polymerase chain reaction (RT-PCR) for detection of MECT1-MAML2 fusion transcript. The CGH analysis showed an overrepresentation of chromosome X and losses of entire chromosomes or regions on chromosome 1, 2, and 15 as the most frequent copy number changes. In 37% of the analysed tumors a MAML2-rearrangement by interphase FISH was detected, whereas 58% of the samples showed expression of MECT1-MAML2 fusion transcript. We conclude that the presence of MAML2-rearrangement as well as of MECT1-MAML2 fusion transcript may reflect a more favourable prognosis and may be a useful marker for clinical prediction of the biological behavior of these tumors as previously reported.
Subject(s)
Carcinoma, Mucoepidermoid/genetics , Chromosome Aberrations , Chromosomes, Human, Pair 11 , Oncogene Proteins, Fusion/genetics , Salivary Gland Neoplasms/genetics , Adult , Aged , Aged, 80 and over , Humans , Male , Middle Aged , RNA, Messenger/analysisABSTRACT
The present study reports for the first time a CRTC3-MAML2 fusion gene in a mucoepidermoid carcinoma, as determined by RT-PCR and sequencing. We screened a total of 67 formalin-fixed, paraffin-embedded mucoepidermoid carcinomas for the presence of chimeric genes. In one of these samples, a CRTC3-MAML2 fusion gene was detected. Thus, this report demonstrates the existence of a fusion of MAML2 with CREB regulated transcriptional coactivator CRTC3 additional to the already known fusion of MAML2 and CRTC1. Both gene fusions seem to result in an identical tumor phenotype and the fusion genes CRTC1-MAML2 and CRTC3-MAML2 may play a similar role in the development of mucoepidermoid carcinomas.