• Title, Summary, Keyword: RET proto-oncogene

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RET Proto-Oncogene Mutation in Medullary Thyroid Carcinoma (갑상선 수질암 조직에서 RET 원암유전자의 돌연변이 양상)

  • Chung Woong-Youn;Song Hyeun-Jung;Cho Nam-Hoon;Park Cheong-Soo
    • Korean Journal of Head & Neck Oncology
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    • v.18 no.1
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    • pp.3-10
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    • 2002
  • Background: The molecular pathogenesis of hereditary medullary thyroid carcinoma is well known to be associated with germ-line mutation in the RET proto-oncogene and sporadic medullary thyroid carcinoma has been shown to carry somatic RET mutation especially in exon 13 and 16. The aim of this study is to evaluate the genetic background in the pathogenesis of the sporadic medullary thyroid carcinoma which shows extremely high incidence in Korea. Materials and Methods: Direct DNA sequencing for RET exon 13 and 16, as well as immunohistochemistrical assay for a monoclonal RET antibody were performed from 20 cases of archival tissues of medullary thyroid carcinoma. Results: Monoclonal RET antibody with C-terminal epitope showed comparatively stronger expression in tumor cells than in normal tissues and immunoreactive area in the tumor was $66.0{\pm}40.1%$. Direct sequencing of RET exon 13 revealed 4 cases of mis-sense mutations in Codon 778, Codon 767, and both in Codon 768 and 778. One case showed a silent mutation (ACG-ACT) in RET exon 16 (Codon 926). Conclusions: The strong RET immunoreactivity of medullary thyroid carcinoma may suggest that there could be a genetic alteration in oncoprotein level. RET proto-oncogene mutation may be involved in the evolutional process of medullary thyroid carcinoma in the aspect of molecular basis.

RET Proto Oncogene Mutation Detection and Medullary Thyroid Carcinoma Prevention

  • Yeganeh, Marjan Zarif;Sheikholeslami, Sara;Hedayati, Mehdi
    • Asian Pacific Journal of Cancer Prevention
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    • v.16 no.6
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    • pp.2107-2117
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    • 2015
  • Thyroid cancer is the most common endocrine neoplasia. The medullary thyroid carcinoma (MTC) is one of the most aggressive forms of thyroid malignancy,accounting for up to 10% of all types of this disease. The mode of inheritance of MTC is autosomal dominantly and gain of function mutations in the RET proto-oncogene are well known to contribute to its development. MTC occurs as hereditary (25%) and sporadic (75%) forms. Hereditary MTC has syndromic (multiple endocrine neoplasia type 2A, B; MEN2A, MEN2B) and non-syndromic (Familial MTC, FMTC) types. Over the last two decades, elucidation of the genetic basis of tumorigenesis has provided useful screening tools for affected families. Advances in genetic screening of the RET have enabled early detection of hereditary MTCs and prophylactic thyroidectomy for relatives who may not show any symptom sof the disease. In this review we emphasize the main RET mutations in syndromic and non syndromic forms of MTC, and focus on the importance of RET genetic screening for early diagnosis and management of MTC patients, based on American Thyroid Association guidelines and genotype-phenotype correlation.

Characterization of Wild-Type and Mutated RET Proto-Oncogene Associated with Familial Medullary Thyroid Cancer

  • Masbi, Mohammad Hosein;Mohammadiasl, Javad;Galehdari, Hamid;Ahmadzadeh, Ahmad;Tabatabaiefar, Mohammad Amin;Golchin, Neda;Haghpanah, Vahid;Rahim, Fakher
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.5
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    • pp.2027-2033
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    • 2014
  • Background: We aimed to assess RET proto-oncogene polymorphisms in three different Iranian families with medullary thyroid cancer (MTC), and performed molecular dynamics simulations and free energy stability analysis of these mutations. Materials and Methods: This study consisted of 48 patients and their first-degree relatives with MTC confirmed by pathologic diagnosis and surgery. We performed molecular dynamics simulations and free energy stability analysis of mutations, and docking evaluation of known RET proto-oncogene inhibitors, including ZD-6474 and ponatinib, with wild-type and mutant forms. Results: The first family consisted of 27 people from four generations, in which nine had the C.G2901A (P.C634Y) mutation; the second family consisted of six people, of whom three had the C.G2901T (P.C634F) mutation, and the third family, who included 12 individuals from three generations, three having the C.G2251A (P.G691S) mutation. The automated 3D structure of RET protein was predicted using I-TASSER, and validated by various protein model verification programs that showed more than 96.3% of the residues in favored and allowed regions. The predicted instability indices of the mutated structures were greater than 40, which reveals that mutated RET protein is less thermo-stable compared to the wild-type form (35.4). Conclusions: Simultaneous study of the cancer mutations using both in silico and medical genetic procedures, as well as onco-protein inhibitor binding considering mutation-induced drug resistance, may help in better overcoming chemotherapy resistance and designing innovative drugs.

EGF Induced RET Inhibitor Resistance in CCDC6-RET Lung Cancer Cells

  • Chang, Hyun;Sung, Ji Hea;Moon, Sung Ung;Kim, Han-Soo;Kim, Jin Won;Lee, Jong Seok
    • Yonsei Medical Journal
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    • v.58 no.1
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    • pp.9-18
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    • 2017
  • Purpose: Rearrangement of the proto-oncogene rearranged during transfection (RET) has been newly identified potential driver mutation in lung adenocarcinoma. Clinically available tyrosine kinase inhibitors (TKIs) target RET kinase activity, which suggests that patients with RET fusion genes may be treatable with a kinase inhibitor. Nevertheless, the mechanisms of resistance to these agents remain largely unknown. Thus, the present study aimed to determine whether epidermal growth factor (EGF) and hepatocyte growth factor (HGF) trigger RET inhibitor resistance in LC-2/ad cells with CCDC6-RET fusion genes. Materials and Methods: The effects of EGF and HGF on the susceptibility of a CCDC6-RET lung cancer cell line to RET inhibitors (sunitinib, E7080, vandetanib, and sorafenib) were examined. Results: CCDC6-RET lung cancer cells were highly sensitive to RET inhibitors. EGF activated epidermal growth factor receptor (EGFR) and triggered resistance to sunitinib, E7080, vandetanib, and sorafenib by transducing bypass survival signaling through ERK and AKT. Reversible EGFR-TKI (gefitinib) resensitized cancer cells to RET inhibitors, even in the presence of EGF. Endothelial cells, which are known to produce EGF, decreased the sensitivity of CCDC6-RET lung cancer cells to RET inhibitors, an effect that was inhibited by EGFR small interfering RNA (siRNA), anti-EGFR antibody (cetuximab), and EGFR-TKI (Iressa). HGF had relatively little effect on the sensitivity to RET inhibitors. Conclusion: EGF could trigger resistance to RET inhibition in CCDC6-RET lung cancer cells, and endothelial cells may confer resistance to RET inhibitors by EGF. E7080 and other RET inhibitors may provide therapeutic benefits in the treatment of RET-positive lung cancer patients.