THE 2 GENES GENERATING RET PTC3 ARE LOCALIZED IN CHROMOSOMAL BAND-10Q11.2/

PCR analysis of DNA from a selected panel of human-rodent somatic cell hybrids and fluorescent in situ hybridization (FISH) analysis allowed us to localize the human ELE1 gene. This previously uncharacterized g ene is fused with the tyrosine kinase (tk) domain of the RET proto-onc ogene to generate the oncogenic sequence RET/PTC3, thus providing a th ird example of RET oncogenic activation in papillary thyroid carcinoma s. ELE1 was localized to band 10q11.2, the subband where RET also maps , at a minimum distance of more than 500 kb from the proto-oncogene. T he fusion event corresponding to the rearrangement reciprocal to that leading to the formation of RET/PTC3 was also identified and character ized. The karyotype of two RET/PTC3 positive tumors did not show any e vidence of chromosome 10 abnormalities. The data indicate that a cytog enetically undetectable paracentric inversion within 10q11.2 generates RET/PTC3. (C) 1994 Wiley-Liss, Inc.