FUSION TRANSCRIPTS BETWEEN THE HMGIC GENE AND RTVL-H-RELATED SEQUENCES IN MESENCHYMAL TUMORS WITHOUT CYTOGENETIC ABERRATIONS

Chromosomal abnormalities of the region 12q13-q15 are very frequent am ong human benign tumors mainly of mesenchymal origin such as uterine l eiomyomas, pleomorphic adenomas, lipomas, or pulmonary chondroid hamar tomas. Because of these cytogenetic aberrations the HMGI-C gene (HGMW- approved symbol HMGIC) becomes rearranged, with most of the breakpoint s located in the large intron 3. In two pulmonary chondroid hamartomas from different patients and one uterine leiomyoma with apparently nor mal karyotypes, we found identical RTVL-H 3' LTRs fused as ectopic seq uences to exon 3 of HMGI-C. Screening of genomic cosmid and plasmid cl ones derived from intron 3 of the HMGI-C gene for the presence of thes e RTVL-H sequences showed a cluster of these retrotransposon-like sequ ences in this region of HMGI-C. Comparing the RTVL-H sequence found in these tumors to known sequences from the literature revealed high hom ology to known RTVL-H elements. (C) 1996 Academic Press, Inc.