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Activation of the RET protooncogene through somatic rearrangements represents the most common genetic alteration in papillary thyroid carcinoma (PTC). Three main rearranged forms of RET have been described: RET/PTC1 and RET/PTC3, which arise from a paracentric inversion of the long arm of chromosome 10, and RET/PTC2, which originates from a 10;17 translocation. We have developed a dual-color FISH approach to detect RET/PTC rearrangements in interphase nuclei of thyroid lesions. By using a pool of three cosmids encompassing the RET chromosome region and a chromosome 10 centromeric probe, we could discriminate between the presence of an inversion (RET/PTC1 and RET/PTC3) or a translocation (RET/PTC2). We have investigated a series of thyroid tissue samples from Italian and French patients corresponding to a total of 69 PTCs and 22 benign lesions. Among PTCs, 13 (18.8%) showed a RET rearrangement, and 11 (15.9%) of these carried an inversion (RET/PTC1 or RET/PTC3) in more than 10% of the nuclei examined. Activated forms of RET were also observed in three adenomas. RT-PCR analysis on the same samples confirmed the presence and the type of rearrangement predicted using FISH analysis. An interesting difference in the frequency and type of RET rearrangements was detected between the Italian and the French patients. Furthermore, we identified a putative novel type of rearrangement in at least one PTC sample. Several PTCs carried a significant number of cells characterized by a trisomy or a tetrasomy of chromosome 10. Overall, the FISH approach in interphase nuclei represents a powerful tool for detecting, at the single cell level, RET/PTC rearrangements and other anomalies involving the RET chromosome region. Copyright © 2000 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

HOX11L1 is a homeobox gene involved in peripheral nervous system development as confirmed by knockout mice exhibiting megacolon with enteric ganglia, a phenotype associated in human with Intestinal Neuronal Dysplasia (IND). Using FISH and radiation hybrids we have localized HOX11L1 to human chromosome 2p13.1→p12, in a 14-cR interval between WI-5987 (D2S2088) and GCT1B4 (D2S2497), and confirmed the synteny between mouse 6C3–D1 and human 2p13.1→p12 chromosomes by mapping an EST cDNA clone corresponding to mouse HOX11L1 (Tlx2 ). [ABSTRACT FROM AUTHOR]

This article reveals the information about mapping of HOX11L2 gene to human chromosome band 5q35.1 and of its murine homolog to mouse chromosome bands 11A4-A5 by in situ hybridization. Primers designed on the basis of the human HOX11L2 gene sequence were used to screen the CEPH human Mega-YAC library by DNA amplification at the annealing temperature of 62 degree celsius. Results indicate that two overlapping human YAC clones were identified. Fluorescence in situ hybridization experiments localized the two YAC clones on chromosome 5q35.1. Results of radiation hybrid panel are also discussed herein.