Project description:Salivary gland myoepithelial tumors are relatively uncommon tumors with an unpredictable clinical course. More knowledge about their genetic profiles is necessary to identify novel predictors of disease. In this study, we subjected 27 primary tumors (15 myoepitheliomas and 12 myoepithelial carcinomas) to genome-wide microarray-based comparative genomic hybridization (array CGH). We set out to delineate known chromosomal aberrations in more detail and to unravel chromosomal differences between benign myoepitheliomas and myoepithelial carcinomas. Patterns of DNA copy number aberrations were analyzed by unsupervised hierarchical cluster analysis. Both benign and malignant tumors revealed a limited amount of chromosomal alterations (median of 5 and 7.5 respectively). In both tumor groups, high frequency gains (≥20%) were found mainly at loci of growth factors and growth factor receptors (e.g. PDGF, FGF(R)s, and EGFR). In myoepitheliomas, high frequency losses (≥20%) were detected at regions of proto-cadherins. Cluster analysis of the array CGH data identified three clusters. Differential copy numbers on chromosome arm 8q and chromosome 17 set the clusters apart. Cluster 1 contained a mixture of the two phenotypes (n=10), cluster 2 included mostly benign tumors (n=10), and cluster 3 only contained carcinomas (n=7). Supervised analysis between malignant and benign tumors revealed a 36 Mbp-region at 8q being more frequently gained in malignant tumors (p=0.007, FDR=0.05). This is the first study investigating genomic differences between benign and malignant myoepithelial tumors of the salivary glands at a genomic level. Both unsupervised and supervised analysis of the genomic profiles revealed chromosome arm 8q to be involved in the malignant phenotype of salivary gland myoepitheliomas.
Project description:In this study, we present a case of parotid gland de novo carcinosarcoma. Salivary gland carcinosarcoma (or true malignant mixed tumor) is a rare biphasic neoplasm, composed of both malignant epithelial and malignant mesenchymal components. It is yet unclear whether these two phenotypes occur by collision of two independent tumors or if they are of clonal origin. To analyze the clonality of the different morphologic tumor components, oligonucleotide microarray-based comparative genomic hybridization (oaCGH) was performed on the carcinoma and the sarcoma entity separately. This technique enables a high-resolution, genome-wide overview of the chromosomal alterations in the distinct tumor elements. Analysis of both fractions showed a high number of DNA copy number changes. Losses were more prevalent than gains (82 and 49, respectively). The carcinomatous element displayed more chromosomal aberrations than the sarcomatous component. Specific amplifications of MUC20 (in mesenchymal element) and BMI-1 (in both elements) loci were observed. Overall homology between the two genomic profiles was 75%. DNA copy number profiles of the epithelial and mesenchymal components in this salivary gland carcinosarcoma displayed extensive overlap, indicating a monoclonal origin. Since losses are shared to a larger extent than gains, they seem to be more essential for initial oncogenic events. Furthermore, specific amplifications of a mucin and a Polycomb group gene imply these proteins in the tumorigenesis of carcinosarcomas.
Project description:Invasive malignant pleomorphic adenoma (IMPA) results from the malignant transformation of pleomorphic adenoma (PA). The former is a high-grade malignant tumor, whereas the latter is a benign opposite. Study on the molecular mechanism in the progression of PA to IMPA will be of benefit to elucidate the reasons for different biological behaviors among these salivary gland tumors with the same origin. But there is no valuable and non-invasive biomarker to screen IMPA currently. Studies showed many salivary molecules can detect several systemic diseases. We aimed to investigate whether salivary mRNAs (mRNA) can act as a biomarker to detect IMPA.
Project description:Salivary exosomes were collected from healthy people and patients with benign and malignant tumors, and small RNA sequencing was performed to screen differential small Rnas for tumor screening