title: RET receptor expression in thyroid follicular epithelial cell-derived tumors.
abstract: The RET proto-oncogene encodes a receptor tyrosine kinase for transforming growth factor-beta-related neurotrophic factors, which include GDNF and neurturin. The expression of RET proto-oncogene was detected in several tissues, such as spleen, thymus, lymph nodes, salivary gland, and spinal cord, and in several neural crest-derived cell lines. RET expression in the thyroid gland was reported to be restricted to neural crest-derived C cells. The presence of RET mRNA or protein has not yet been reported in thyroid follicular cells. We previously demonstrated the expression of oncogenic rearranged versions of RET in papillary thyroid carcinomas: tumors derived from thyroid follicular cells. To assess the expression of the normal RET proto-oncogene in follicular cells, we analyzed its expression in a panel of neoplasias originating from thyroid follicular epithelial cells: papillary carcinomas and both follicular adenomas and carcinomas. We also demonstrated the presence of RET normal transcripts in two follicular thyroid carcinoma lymph node metastases. Moreover, we found the presence of the RET/ELE1 transcript, the reciprocal complementary form of the oncogenic fusion transcript ELE1/RET, in a papillary thyroid carcinoma specimen expressing the RET/PTC3 oncogene, thus demonstrating that the RET promoter is active in those cells after rearrangement. Finally, we show that in a papillary carcinoma-derived cell line expressing the proto-RET receptor and the related GFRalpha2 co-receptor, GDNF treatment induced RET tyrosine phosphorylation and subsequent signal transduction pathway, indicating that RET could be active in thyroid follicular cells.
authors.affiliation: Division of Experimental Oncology, Istituto Nazionale Tumori, Milan, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Bunone
authors.forename: M
authors.initials: M
authors.lastname: Uggeri
authors.forename: P
authors.initials: P
authors.lastname: Mondellini
authors.forename: M A
authors.initials: MA
authors.lastname: Pierotti
authors.forename: I
authors.initials: I
authors.lastname: Bongarzone
mesh_terms: D018263:Adenocarcinoma, Follicular / Q000378:metabolism*; D000231:Adenocarcinoma, Papillary / Q000378:metabolism; D001483:Base Sequence; D015153:Blotting, Western; D029721:Drosophila Proteins; D051100:Glial Cell Line-Derived Neurotrophic Factor; D051097:Glial Cell Line-Derived Neurotrophic Factor Receptors; D006801:Humans; D008969:Molecular Sequence Data; D009414:Nerve Growth Factors; D009419:Nerve Tissue Proteins / Q000378:metabolism; D010766:Phosphorylation; D010982:Platelet-Derived Growth Factor / Q000378:metabolism; D011233:Precipitin Tests; D000090063:Proto-Oncogene Mas; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis*; D051096:Proto-Oncogene Proteins c-ret; D020794:Receptor Protein-Tyrosine Kinases / Q000096:biosynthesis*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D013964:Thyroid Neoplasms / Q000378:metabolism*; D014407:Tumor Cells, Cultured
chemical_list: D029721:Drosophila Proteins; C495039:GDNF protein, human; C494990:GFRA2 protein, human; D051100:Glial Cell Line-Derived Neurotrophic Factor; D051097:Glial Cell Line-Derived Neurotrophic Factor Receptors; C000715470:MAS1 protein, human; D009414:Nerve Growth Factors; D009419:Nerve Tissue Proteins; D010982:Platelet-Derived Growth Factor; D000090063:Proto-Oncogene Mas; D011518:Proto-Oncogene Proteins; D051096:Proto-Oncogene Proteins c-ret; D020794:Receptor Protein-Tyrosine Kinases; C416649:Ret protein, Drosophila