The Open Cell Signaling Journal
2010, 2 : 13-22Published online 2010 December 15. DOI: 10.2174/1876390101002010013
Publisher ID: TOCELLSJ-2-13
RESEARCH ARTICLE
‘Chromosomal Rainbows’ Detect Oncogenic Rearrangements of Signaling Molecules in Thyroid Tumors
2 Department of Cardiothoracic Anaesthesia and Intensive Care, Imperial College Healthcare NHS Trust, Hammersmith Hospital, London, UK
3 Department of Anesthesiology, German Heart Institute, Berlin, Germany
4 Department of Surgery University of California, San Francisco, CA 94115, USA
5 Clinical Laboratories, University of California, San Francisco, CA 94107, USA
6 Laparoscopic Associates of San Francisco, San Francisco, CA 94115, USA
7 National Institute of Science and Technology Policy (NISTEP), Ministry of Education, Culture, Sports, Science and Technology, Tokyo 100-0005, Japan
8 Division Genetics of Skin Carcinogenesis, German Cancer Research Center (DKFZ), Heidelberg, D-69120, Germany
9 Reprogenetics, LLC, Livingston, NJ 07039, USA
* Address correspondence to this author at the Department of Cardiothoracic Anaesthesia and Intensive Care, Imperial College Healthcare NHS Trust, Hammersmith Hospital, London W12 0HS, UK; Tel: +44-2033133991; Fax: +44-2033135373; E-mail: benobrien@doctors.org.uk
ABSTRACT
Altered signal transduction can be considered a hallmark of many solid tumors. In thyroid cancers the receptor tyrosine kinase (rtk) genes NTRK1 (Online Mendelian Inheritance in Man = OMIM *191315, also known as ‘TRKA’), RET (‘Rearranged during Transfection protooncogene’, OMIM *164761) and MET (OMIM *164860) have been reported as activated, rearranged or overexpressed. In many cases, a combination of cytogenetic and molecular techniques allows elucidation of cellular changes that initiate tumor development and progression. While the mechanisms leading to overexpression of the rtk MET gene remain largely unknown, a variety of chromosomal rearrangements of the RET or NTKR1 gene could be demonstrated in thyroid cancer. Abnormal expressions in these tumors seem to follow a similar pattern: the rearrangement translocates the 3’- end of the rtk gene including the entire catalytic domain to an expressed gene leading to a chimeric RNA and protein with kinase activity. Our research was prompted by an increasing number of reports describing translocations involving ret and previously unknown translocation partners.
We developed a high resolution technique based on fluorescence in situ hybridization (FISH) to allow rapid screening for cytogenetic rearrangements which complements conventional chromosome banding analysis. Our technique applies simultaneous hybridization of numerous probes labeled with different reporter molecules which are distributed along the target chromosome allowing the detection of cytogenetic changes at near megabasepair (Mbp) resolution. Here, we report our results using a probe set specific for human chromosome 10, which is altered in a significant portion of human thyroid cancers (TC’s). While rendering accurate information about the cytogenetic location of rearranged elements, our multilocus, multi-color analysis was developed primarily to overcome limitations of whole chromosome painting (WCP) and chromosome banding techniques for fine mapping of breakpoints in papillary thyroid cancer (PTC).