Clinical and molecular evaluation of the sporadic medullary thyroid carcinoma in young patients

• Grant number: 19/20300-5
• Support type: Regular Research Grants
• Duration: December 01, 2020 - November 30, 2022
• Field of knowledge: Health Sciences - Medicine - Medical Clinics
• Principal researcher: Ana Amélia Fialho de Oliveira Hoff
• Grantee: Ana Amélia Fialho de Oliveira Hoff
• Home Institution: Instituto do Câncer do Estado de São Paulo Octavio Frias de Oliveira (ICESP). Coordenadoria de Serviços de Saúde (CSS). Secretaria da Saúde (São Paulo - Estado). São Paulo , SP, Brazil
• Assoc. researchers: Alexander Augusto de Lima Jorge ; Luciana Audi de Castro Neves ; Maria Aparecida Nagai

Abstract

Medullary thyroid carcinoma (MTC) is a neuroendocrine tumor arising from the parafollicular C cells. This tumor can be sporadic or familial in 25% of the cases. When hereditary, it is associated with the multiple endocrine neoplasia type 2 syndrome (MEN2), an autosomal dominant disorder caused by germline mutations of the RET proto-oncogene, classified in 2 subtypes: MEN2A e MEN2B. The high penetrance of MTC in MEN2 patients and the high rate of cure by prophylactic thyroidectomy are reasons for recommending RET gene analysis to all patients with MTC despite family history and age of diagnosis (1). The mean age of presentation of hereditary MTC varies according to the RET mutation, but generally occurs before the third decade of life and the most aggressive form which is associated with MEN2B (RET Met918Thr mutation) develop MTC within the first year of life (1).Recently, the exome sequencing contributed to the discovery of new genes related to hereditary MTC, the ESR2 and MET genes (2, 3). Sporadic MTC, which by definition is not associated with germline RET mutations, is usually diagnosed by the fourth and sixth decades of life. Genetic analysis of these tumors identified somatic mutations in the RET, HRAS and KRAS genes and less frequently in the MDC1 and ATM genes (4 - 16). However, approximately 30% of the sporadic MTC patients did not have tumor genes identified (17).In the literature, tumor exome sequencing studies were done in a few numbers of patients without clinical data correlation. Until now, there are no studies including specific subgroups of patients, like the sporadic MTC patients with aggressive and early disease onset. The objective of this study is to analyze genetic alterations in the carcinogenesis of sporadic MTC patients with premature disease onset and aggressive disease behavior. (AU)