A potential liquid biopsy biomarker: in vitro and in vivo study of the pathogenic role of NCOR1 on thyroid oncocytic carcinoma

• Grant number: 23/03391-2
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate (Direct)
• Start date: July 15, 2023
• End date: July 14, 2024
• Field of knowledge: Biological Sciences - Genetics - Human and Medical Genetics
• Principal Investigator: Janete Maria Cerutti
• Grantee: Débora Mota Dias Thomaz
• Supervisor: Alexander Birbrair
• Host Institution: Escola Paulista de Medicina (EPM). Universidade Federal de São Paulo (UNIFESP). Campus São Paulo. São Paulo , SP, Brazil
• Institution abroad: University of Wisconsin-Madison (UW-Madison), United States
• Associated to the scholarship: 20/06594-3 - Liquid biopsy as a non-invasive diagnostic and prognostic of thyroid tumors tool, BP.DD

Abstract

Thyroid cancer is the most common endocrine malignancy, and its prevalence has been increasing worldwide, essentially due to the wide use of ultrasound and subsequent fine needle aspiration (FNA) for incidentally discovered thyroid nodules. Oncocytic Thyroid Carcinomas (OTC) have a higher predisposition for neck node soft tissue and distant metastases, decreased avidity for radioactive iodine (RAI) therapy, and a 10-year survival rate of 77%, and, therefore, more aggressive behavior and worse prognosis than other Well-Differentiated Thyroid Carcinomas (DTC). However, studies especially focusing on OTC are rare and there is still no consensus on the optical treatment option, and little is known about the molecular events associated with its genesis and progression. Mutations typical of other DTC, including RAS, TERT, BRAF, and fusions involving RET::PTC, ETV6::NTRK3, EML4/ALK, and PAX/PPARG are uncommon in OTC. Recently, to discover new candidate driver genes that could better classify thyroid nodules into benign and malignant groups, our group performed an RNA-Sequencing analysis of 14 thyroid carcinomas that are a source of pre-surgical diagnostic errors such as FTC, OTC, and Follicular Variant of Papillary Thyroid Carcinoma (fPTC) that were negative for the main driver mutations described in thyroid cancer. Using next generation sequencing approach, we identified a recurrent Nuclear Receptor Corepressor 1 (NCOR1) missense variant p.H2252Y exclusively in 2 out of 3 OTC. NCOR1 has a unique role in the regulation of thyroid hormone signaling and has been found mutated or lost in several human cancers. Therefore, to better understand the role of the NCOR1 p.H2252Y variant in the OTC pathogenesis, we assessed the prevalence of NCOR1 p.H2252Y in an expanded set of samples, including benign and malignant thyroid neoplasms by sanger sequencing. In the sample set comprised of 188 thyroid samples (37 OTA, 23 OTC, 30 FTA, 30 FTC, 30 PTC, 30 follicular variants of PTC, and 8 NIFTP), we identified the NCOR1 p.H2252Y variant in 6/23 (26%) of OTC while it was not identified in any other thyroid neoplasm. To investigate whether there was NCOR1 specific copy number alteration (CNA) or loss of heterozygosity (LOH), we performed fluorescent in situ hybridization (FISH) using a chromosome 17 alpha-satellite probe on mutated samples. Recurrent LOH was seen in NCOR1-mutated OTC samples. Finally, immunohistochemistry performed on mutated and non-mutated OTC along with OTA samples showed that NCOR1 protein is not present on mutated tumors and adjacent thyroid tissues, while it was detected on OTA, suggesting that this protein may act as a tumor suppressor in oncocytic thyroid tumors (Thomaz DMD et al., manuscript in preparation). These yet unpublished data suggest that NCOR1 may be relevant to OCT pathogenesis, and pathogenic variant in this gene has potential use as an OTC molecular marker, which might positively impact the preoperative differential diagnosis of thyroid nodules commonly classified as indeterminate on FNA analysis and detect disease recurrence/persistence. This project sought to investigate the in vivo and in vitro role of NCOR1wt and NCOR1H2252Y in the pathogenesis and progression of oncocytic thyroid tumors. (AU)