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.

Studies of genomic imbalances and the MYB-NFIB gene fusion in polymorphous low-grade adenocarcinoma of the head and neck.

Polymorphous low-grade adenocarcinoma (PLGA) is a malignancy predominantly originating from the minor salivary glands. The molecular events underlying the pathogenesis of PLGA is poorly understood and no recurrent genetic aberrations have so far been identified. We used genome-wide, high-resolution aCGH analysis to explore genomic imbalances in 9 cases of PLGA. Because of the well-known morphologic similarities between PLGA and adenoid cystic carcinoma (ACC) we also analyzed all tumors for expression of the recently identified ACC-associated MYB-NFIB gene fusion. aCGH analysis revealed that the PLGA genome contains comparatively few copy number alterations (CNAs). Gains/losses of whole chromosomes or chromosome arms were more than twice as common as partial CNAs. Two cases showed gain of chromosome 8 and one case each gain of chromosome 9, loss of chromosome 22 and loss of the Y chromosome. One case showed loss of the entire 6q arm and one case an interstitial deletion of a 33-Mb segment within 6q22.1-q24.3. This region contains the MYB oncogene and the candidate tumor suppressor gene PLAGL1. RT-PCR analysis revealed that one of the 9 PLGAs expressed the ACC-associated MYB-NFIB gene fusion, illustrating the diagnostic difficulties associated with the diagnosis of these morphologically partly overlapping entities. Taken together, our findings indicate that the PLGA genome is genetically stable and contains comparatively few CNAs which is in line with the clinical observation that PLGA is a slow-growing, low-grade carcinoma with low metastatic potential.

Effects of cisplatin, alpha-interferon, and 13-cis retinoic acid on the expression of Fas (CD95), intercellular adhesion molecule-1 (ICAM-1), and epidermal growth factor receptor (EGFR) in oral cancer cell lines.

BACKGROUND: Previous studies showed that many chemotherapeutic agents can induce immuno-suppression at therapeutic drug concentrations whereas low drug doses induce immuno-augmentation. METHODS: The effect of low-dose cisplatin, interferon-alpha, and 13-cis retinoic acid on receptors involved in immune-mediated apoptosis (Fas/CD95), cell growth (epidermal growth factor receptor) and lymphocyte adhesion (intercellular adhesion molecule-1) was investigated in two oral cancer cell lines (UT-SCC-20A and UT-SCC-24A). Different methods for cell preparation were studied: mechanical and enzymatic detachment, and culture on chamber slides. Receptor expression was investigated using immunohistochemical staining. The amount of soluble and cell-bound Fas was determined with the ELISA technique, and the functional relevance of Fas expression, apoptosis induction, was analyzed. RESULTS: Cisplatin enhanced cytoplasm and membrane staining for Fas in both cell lines. After cisplatin treatment, the amount of soluble Fas was increased in UT-SCC-20A cultures, but no effect was observed in the UT-SCC-24A cell line. Apoptosis, measured as enhanced caspase-3 activity, was induced by an agonistic Fas antibody (CH11) after cisplatin treatment in UT-SCC-24A cells. CONCLUSIONS: Low-dose cisplatin treatment enhanced Fas expression in both cell lines and increased susceptibility to apoptosis in one of them.

Effects of cytokines on matrix metalloproteinase expression in oral squamous cell carcinoma in vitro.

CONCLUSIONS: The intra-tumoral cytokines IL-6, hepatocyte growth factor (HGF) and tumour necrosis factor-a (TNF-a) stimulate oral cancer cells to enhanced secretion of matrix metalloproteinase (MMP)-1 and -9. These results contribute to an understanding of the extracellular events necessary for tumour progression. OBJECTIVE: MMPs play an important role in enhanced intra-tumoral proteolytic activity, promoting angiogenesis and invasion by acting on extracellular matrix substances. Cytokines secreted by tumour-infiltrating immune cells, fibroblasts and tumour cells can modulate MMP expression and secretion by cancer cells. The objective of this study was to investigate the effects of IL-6, soluble IL-6 receptor (sIL-6R), HGF, TNF-a and IL-8 on MMP-1, -2 and -9 expression by two oral squamous cell carcinoma cell lines (UT-SCC-20A and -24A). MATERIAL AND METHODS: ELISA was used to analyse secretion of total MMP protein and gelatin zymography was used for activity analysis. RESULTS: IL-6 had a moderate stimulatory effect on MMP-1 secretion in both cell lines, whereas sIL-6R had no effect. When these cytokines were added together, a dose-dependent, synergistic stimulatory effect was observed. HGF also upregulated MMP-1 secretion, especially in one cell line (UT-SCC-24A), and a synergistic effect was observed when HGF was added to IL-6 in both cell lines. MMP-9 secretion by UT-SCC-24A was increased when stimulated with HGF and IL-6 combined with sIL-6R, whereas no effect was found in the other cell line. TNF-a stimulated MMP-9 secretion in both cell lines, but only stimulated MMP-1 secretion in one (UT-SCC-24A). The zymographic results were consistent with the ELISA results, indicating an upregulation of active enzyme when a stimulatory effect on protein expression was detected.