Genomic profiles and CRTC1-MAML2 fusion distinguish different subtypes of mucoepidermoid carcinoma.

Mucoepidermoid carcinoma is the most common salivary gland malignancy, and includes a spectrum of lesions ranging from non-aggressive low-grade tumors to aggressive high-grade tumors. To further characterize this heterogeneous group of tumors we have performed a comprehensive analysis of copy number alterations and CRTC1-MAML2 fusion status in a series of 28 mucoepidermoid carcinomas. The CRTC1-MAML2 fusion was detected by RT-PCR or fluorescence in situ hybridization in 18 of 28 mucoepidermoid carcinomas (64%). All 15 low-grade tumors were fusion-positive whereas only 3 of 13 high-grade tumors were fusion-positive. High-resolution array-based comparative genomic hybridization revealed that fusion-positive tumors had significantly fewer copy number alterations/tumor compared with fusion-negative tumors (1.5 vs 9.5; P=0.002). Twelve of 18 fusion-positive tumors had normal genomic profiles whereas only 1 out of 10 fusion-negative tumors lacked copy number alterations. The profiles of fusion-positive and fusion-negative tumors were very similar to those of low- and high-grade tumors. Thus, low-grade mucoepidermoid carcinomas had significantly fewer copy number alterations/tumor compared with high-grade mucoepidermoid carcinomas (0.7 vs 8.6; P<0.0001). The most frequent copy number alterations detected were losses of 18q12.2-qter (including the tumor suppressor genes DCC, SMAD4, and GALR1), 9p21.3 (including the tumor suppressor genes CDKN2A/B), 6q22.1-q23.1, and 8pter-p12.1, and gains of 8q24.3 (including the oncogene MAFA), 11q12.3-q13.2, 3q26.1-q28, 19p13.2-p13.11, and 8q11.1-q12.2 (including the oncogenes LYN, MOS, and PLAG1). On the basis of these results we propose that mucoepidermoid carcinoma may be subdivided in (i) low-grade, fusion-positive mucoepidermoid carcinomas with no or few genomic imbalances and favorable prognosis, (ii) high-grade, fusion-positive mucoepidermoid carcinomas with multiple genomic imbalances and unfavorable prognosis, and (iii) a heterogeneous group of high-grade, fusion-negative adenocarcinomas with multiple genomic imbalances and unfavorable outcome. Taken together, our studies indicate that molecular genetic analysis can be a useful adjunct to histologic scoring of mucoepidermoid carcinoma and may lead to development of new clinical guidelines for management of these patients.

High-resolution oligonucleotide array comparative genomic hybridization study and methylation status of the RPS14 gene in de novo myelodysplastic syndromes.

In myelodysplastic syndromes (MDS), close to one half of patients do not have any visible karyotypic change. In order to study submicroscopic genomic alterations, we applied high-resolution array comparative genomic hybridization techniques (aCGH) in 37 patients with de novo MDS. Furthermore, we studied the methylation status of the RPS14 gene in 5q deletion (5q21.3q33.1) in 24 patients. In all, 21 of the 37 patients (57%) had copy number alterations. The most frequent copy number losses with minimal common overlapping areas were 5q21.3q33.1 (21%) and 7q22.1q33 (19%); the most frequent copy number gain was gain of the whole chromosome 8 (8%). Recurrent, but less frequent copy number losses were detected in two cases each: 11q14.1q22.1, 11q22.3q24.2, 12p12.2p13.31, 17p13.2, 18q12.1q12.2, 18q12.3q21.3, 18q21.2qter, and 20q11.23q12; the gains 8p23.2pter, 8p22p23.1, 8p12p21.1, and 8p11.21q21.2 were similarly found in two cases each. No homozygous losses or amplifications were observed. The RPS14 gene was not methylated in any of the patients.

Recurrent and multiple bladder tumors show conserved expression profiles.

BACKGROUND: Urothelial carcinomas originate from the epithelial cells of the inner lining of the bladder and may appear as single or as multiple synchronous tumors. Patients with urothelial carcinomas frequently show recurrences after treatment making follow-up necessary. The leading hypothesis explaining the origin of meta- and synchronous tumors assumes a monoclonal origin. However, the genetic relationship among consecutive tumors has been shown to be complex in as much as the genetic evolution does not adhere to the chronological appearance of the metachronous tumors. Consequently, genetically less evolved tumors may appear chronologically later than genetically related but more evolved tumors. METHODS: Forty-nine meta- or synchronous urothelial tumors from 22 patients were analyzed using expression profiling, conventional CGH, LOH, and mutation analyses. RESULTS: We show by CGH that partial chromosomal losses in the initial tumors may not be present in the recurring tumors, by LOH that different haplotypes may be lost and that detected regions of LOH may be smaller in recurring tumors, and that mutations present in the initial tumor may not be present in the recurring ones. In contrast we show that despite apparent genomic differences, the recurrent and multiple bladder tumors from the same patients display remarkably similar expression profiles. CONCLUSION: Our findings show that even though the vast majority of the analyzed meta- and synchronous tumors from the same patients are not likely to have originated directly from the preceding tumor they still show remarkably similar expressions profiles. The presented data suggests that an expression profile is established early in tumor development and that this profile is stable and maintained in recurring tumors.

Undifferentiated intimal sarcoma of large systemic blood vessels: report of 14 cases with immunohistochemical profile and review of the literature.

Intimal sarcoma (IS) is defined as a malignant tumor arising in the tunica intima of large blood vessels. In systemic circulation, the majority of IS develop in the aorta, where close to three fourths of published cases lack specific differentiation and are called undifferentiated intimal sarcomas (UIS). The remaining cases are intima-associated sarcomas of recognized types, also called differentiated intimal sarcomas (DIS). In this report, we further characterize UIS, including its immunohistochemical profile and results of comparative genomic hybridization. A total of 14 cases of UIS were collected from 17 medical institutions, including slides, blocks, electron photomicrographs, clinical abstracts, and reports of surgical pathology specimens and autopsies. The patients, 7 women and 7 men, were 41 to 85 years of age (median, 65.6 years). Twelve tumors arose from the aorta, one from the left external iliac and femoral arteries, and one in a large systemic vein (the venous tumor was included due to histologic similarity with the arterial lesions). Tumors ranged from 1 cm to over 10 cm in diameter. Histopathology was that of a largely necrotic, poorly differentiated epithelioid and pleomorphic malignant neoplasm relating to the tunica intima. Usually there was only a thin layer of viable tumor cells overlying a large thrombus. All tumors stained at least focally with the endothelial markers CD31 and Fli-1; however, there was otherwise considerable variability in immunophenotype. The distinctive histopathologic appearance of the primary luminal lesion was lost whenever tumor invaded outside the vessel wall (into adventitia and beyond) or in metastatic sites. Such extravascular tumors assumed a variety of patterns reminiscent of undifferentiated pleomorphic sarcoma (UPS; in older literature also known as pleomorphic malignant fibrous histiocytoma, MFH) or other distinct types of sarcomas, including osteosarcoma, angiosarcoma, and rhabdomyosarcoma. The results of comparative genomic hybridization were nonspecific. Eleven patients died of the disease, in an average of 11 months after diagnosis. Three patients are still alive and free of disease at 4, 16, and 27 years. UIS of large systemic vessels represents a distinct clinical entity where intraluminal sarcoma presents with thrombosis and occlusion of large vessels. It is associated with a highly characteristic, although not entirely specific, histology and immunohistochemical phenotype. The histogenesis of UIS is not certain; however, it seems that the cell of origin must leave the confines of the vessel wall to show altered morphology. Although there are rare long-term survivors, UIS behaves as a fully malignant neoplasm that is almost uniformly associated with metastases and tumor-related death.

Characterization of gene expression in major types of salivary gland carcinomas with epithelial differentiation.

Gene expression profiles were studied in 13 cases of salivary gland carcinoma including mucoepidermoid carcinoma (MEC), acinic cell carcinoma (ACC), and salivary duct carcinoma (SDC) using a cDNA array. A total of 162 genes were deregulated. Only 5 genes were overexpressed in all carcinomas including fibronectin 1 (FN1), tissue metalloproteinase inhibitor 1 (TIMP1), biglycan (BGN), tenascin-C (HXB), and insulin-like growth factor binding protein 5 (IGFBP5), whereas 16 genes were underexpressed. The small number of similarly deregulated genes in these carcinoma entities suggests an extensive genetic variation between them. This result agrees with the great histopathological diversity of different entities of salivary gland carcinoma. Furthermore, diversity in gene expression between the carcinoma types was identified also by hierarchical clustering. Each carcinoma entity was clustered together but MEC, SDC, and ACC were separated from each other. Significance analysis of microarrays identified 27 genes expressed differently between the groups. In MEC, overexpressed genes included those of cell proliferation (IL-6 and SFN) and cell adhesion (SEMA3F and COL6A3), whereas many underexpressed genes were related to DNA modification (NTHL1 and RBBP4). Apoptosis-related genes CASP10 and MMP11 were overexpressed in SDC, in accordance with the typical tumor necrosis seen in this entity. An intermediate filament protein of basal epithelial cells, cytokeratin 14 (KRT14) was clearly differently expressed between the 3 types of carcinoma, and can be used as an aid in their differential diagnosis. The array results were validated by RT-PCR and immunohistochemistry.

Proximal-type epithelioid sarcoma: case report and result of comparative genomic hybridization.

BACKGROUND: Epithelioid sarcoma is a rare mesenchymal neoplasm. Recently, a more aggressive, so-called "proximal type" epithelioid sarcoma has been described. CLINICAL CASE: A 40-year-old-woman presented with 5 x 4 cm, erythematous, indurated, non-movable, painful mass on the pubic area. Histopathology demonstrated diffuse tumor-cell infiltration into the subcutaneous and fascia, which was consisted of prominent epithelioid cells and scattered rhabdoid cells. A multinodular growth pattern or granulomatous appearance with central necrosis was not observed. The tumor cells showed positive reactions for vimentin, cytokeratin (AE1/AE3), and CD34. Despite the surgery, left inguinal mass with lymphadenopathy occurred one month later. We also carried out comparative genomic hybridization (CGH) with tumor cells. CGH revealed chromosomal gain of 5q32-qter, 12q24-qter, and 22q. CONCLUSION: We report a case of proximal-type of epithelioid sarcoma, which showed the chromosomal gains of 5q32-qter, 12q24-qter, and 22q by CGH.

Formation of trisomies and their parental origin in hyperdiploid childhood acute lymphoblastic leukemia.

High hyperdiploidy, common in childhood acute lymphoblastic leukemia (ALL) with a favorable prognosis, is characterized by specific trisomies. Virtually nothing is known about its formation or pathogenetic impact. We evaluated 10 patients with ALL using 38 microsatellite markers mapped to 18 of the 24 human chromosomes to investigate the mechanisms underlying hyperdiploidy and to ascertain the parental origin of the trisomies. Based on the results, doubling of a near-haploid clone and polyploidization with subsequent losses of chromosomes could be excluded. The finding of equal allele dosage for tetrasomy 21 suggests that hyperdiploidy originates in a single aberrant mitosis, though a sequential gain of chromosomes other than 21 in consecutive cell divisions remains a possibility. Our study, the first to address experimentally the parental origin of trisomies in ALL, revealed no preferential duplication of maternally or paternally inherited copies of X, 4, 6, 9, 10, 17, 18, and 21. Trisomy 8 was of paternal origin in 4 of 4 patients (P =.125), and +14 was of maternal origin in 7 of 8 patients (P =.0703). Thus, the present results indicate that imprinting is not pathogenetically important in hyperdiploid childhood ALL, with the possible exception of the observed parental skewness of +8 and +14.