Deletion of 1p32-p36 Is the Most Frequent Genetic Change and Poor Prognostic Marker in Adenoid Cystic Carcinoma of the Salivary Glands
ABSTRACT Adenoid cystic carcinoma (ACC) is a relatively uncommon salivary gland malignancy known for its protean phenotypic features and pernicious clinical behavior. Currently, no effective therapy is available for patients with advanced nonresectable, recurrent, and/or metastatic disease. The purpose of this study is to identify prognostic factors other than tumor stage that can be used to predict the outcome of the patients with ACC.
We used comparative genomic hybridization (CGH) to identify copy number aberrations in 53 primary ACCs. Array CGH and fluorescence in situ hybridization analysis was used to validate CGH results on selected cases. We correlated these copy number aberrations with clinicopathologic factors using Pearson's chi2 or by the two-tailed Fisher exact test. The disease-specific survival and disease-free intervals were generated by the Kaplan-Meier product limit method.
Chromosomal losses (n = 134) were more frequent than gains (n = 74). The most frequent genetic change was the loss of 1p32-p36 in 44% of the cases followed by 6q23-q27, and 12q12-q14. The most frequently gained chromosomal regions were 8 and 18. Of the chromosomal aberrations, loss of 1p32-p36 was the only abnormality significantly associated with patient's outcome.
This study, for the first time, identifies loss of 1p32-p36 as a significant aberration in ACC. Molecular characterization of 1p32-36 region using the available genomic technologies may lead to the identification of new genes critical to the development of novel therapeutic targets for this disease copy number aberration.
- SourceAvailable from: Jau-Chen Lin
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- "Epigenetic changes, which are defined as modifications of the chromatin structure without alteration of the primary DNA sequence (Jaenisch & Bird, 2003), may be induced by external factors and are potentially reversible. LOH at human chromosome 1p32 is frequent in various cancers, including lung cancer (Chizhikov et al, 2001; Fong et al, 1996), breast cancer (el-Rifai et al, 1999), meningioma (Kim et al, 2009; Sulman et al, 1998), adenoid cystic carcinoma (Rao et al, 2008) and oligodendroglia (Husemann et al, 1999). Thus, this region of chromosome 1 is expected to contain one or more tumour suppressor genes. "
ABSTRACT: Trop-2, a cell surface glycoprotein, contains both extracellular epidermal growth factor-like and thyroglobulin type-1 repeat domains. Low TROP2 expression was observed in lung adenocarcinoma tissues as compared with their normal counterparts. The lack of expression could be due to either the loss of heterozygosity (LOH) or hypermethylation of the CpG island DNA of TROP2 upstream promoter region as confirmed by bisulphite sequencing and methylation-specific (MS) polymerase chain reaction (PCR). 5-Aza-2'-deoxycytidine treatment on lung cancer cell (CL) lines, CL1-5 and A549, reversed the hypermethylation status and elevated both TROP2 mRNA and protein expression levels. Enforced expression of TROP2 in the lung CL line H1299 reduced AKT as well as ERK activation and suppressed cell proliferation and colony formation. Conversely, silencing TROP2 with shRNA transfection in the less efficiently tumour-forming cell line H322M enhanced AKT activation and increased tumour growth. Trop-2 could attenuate IGF-1R signalling-mediated AKT/β-catenin and ERK activation through a direct binding of IGF1. In conclusion, inactivation of TROP2 due to LOH or by DNA methylation may play an important role in lung cancer tumourigenicity through losing its suppressive effect on IGF-1R signalling and tumour growth.EMBO Molecular Medicine 06/2012; 4(6):472-85. DOI:10.1002/emmm.201200222 · 8.67 Impact Factor
- Ground Penetrating Radar, 2004. GPR 2004. Proceedings of the Tenth International Conference on; 02/2004
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ABSTRACT: The molecular genetic background of salivary gland neoplasms has not been characterized in detail to date. However, interesting target genes which could be used as prognostic and diagnostic molecular biomarkers have already been identified, e.g. CRTC1-MAML2 in mucoepidermoid carcinoma, or PLAG1 and HMGA2 in pleomorphic adenoma. In particular, CRTC1-MAML2 has shown strong diagnostic and prognostic potential in recent years. One of the major advantages of molecular tumor markers is that valid results are obtained on minute cell and/or tissue samples. Due to high-throughput techniques like comparative genome hybridization (CGH), micro- or gene profiling array detection of new marker genes can be expected in the future. This is also true for the most frequent malignant salivary gland tumors after the mucoepidermoid carcinoma, i.e. adenoid cystic carcinomas and acinic cell carcinomas.Der Pathologe 09/2009; 30(6):466-71. · 0.39 Impact Factor