The recent reclassification of a follicular variant of papillary thyroid carcinoma (FVPTC), subset as noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP), aims to avoid overtreatment of patients with an indolent lesion. The diagnosis of NIFTP has recently been revisited using more rigid criteria. This study presents histological and molecular findings and a long clinical follow-up of 94 FVPTC, 40 cases of follicular adenoma (FTA) and 22 cases of follicular carcinoma (FTC) that were classified before the advent of the NIFTP reclassification. All slides were reviewed using these rigid criteria and analysis of numerous sections of paraffin blocks and reclassified as 7 NIFTPs, 2 EFVPTCs, 29 infiltrative FVPTC (IFVPTCs), 57 invasive EFVPTC (I-EFVPTCs), 39 FTAs and 22 FTCs. Remarkably, EFVPTC and NIFTP patients were all free of disease at the end of follow-up and showed no BRAF mutation. Only one NIFTP sample harbored mutations, an NRAS Q61R. PAX8/PPARG fusion was found in I-EFVPTCs and FTC. Although additional studies are needed to identify a specific molecular profile to aid in the diagnosis of lesions with borderline morphological characteristics, we confirmed that the BRAF V600E mutation is an important tool to exclude the diagnosis of NIFTP. We also show that rigorous histopathological criteria should be strongly followed to avoid missing lesions in which more aggressive behavior is present, mainly via the analysis of capsule or vascular invasion and the presence of papillary structures.
Ana Carolina de Jesus Paniza, Thais Biude Mendes, Matheus Duarte Borges Viana, Débora Mota Dias Thomaz, Paula B O Chiappini, Gabriel A Colozza-Gama, Susan Chow Lindsey, Marcos Brasilino de Carvalho, Venâncio Avancini Ferreira Alves, Otavio Curioni, André Uchimura Bastos and Janete Maria Cerutti
Erika Urbano Lima, Ileana G S Rubio, Joaquim Custodio Da Silva, Ana Luiza Galrão, Danielle Pêssoa, Taise Cerqueira Oliveira, Fabiane Carrijo, Igor Silva Campos, Luciano Fonseca Espinheira, Luiz Jose Sampaio, Claudio Rogerio Lima, Janete Maria Cerutti and Helton Estrela Ramos
The inactivation of the tumor-suppressor homeodomain-only protein X (HOPX) usually involves promoter methylation in several cancer types. This study aimed to investigate the HOPX-β mRNA expression and promoter methylation and their clinical relevance in differentiated thyroid cancer (DTC).
Patients and methods
Clinicopathological data and paraffin-embedded thyroid tumor tissues from 21 patients with DTC and 6 with benign tumors (T) and their non-tumor parenchyma (NT) were investigated. Tumor cell lines (FTC238, FTC236 and WRO) were treated with demethylating agent. HOPX-β mRNA expression was assessed by qRT-PCR and methylation status by Q-MSP. Thyroid cancer data from Cancer Genome Atlas (TCGA) was also collected.
HOPX-β mRNA re-expression in two cell lines treated with demethylating agent was observed concomitantly with reduced promoter methylation. Reduced mRNA expression in T group compared to their NT was observed, and reduced protein expression in T compared to NT was observed in three cases. Low mRNA expression with high methylation status was detected in 6/14 DTC samples. High methylation status was associated with older age at diagnosis, recurrent or progressive disease and with the presence of new neoplasm event post initial therapy while hyper-methylation correlated with worse overall survival, worse disease-free status and older age.
A moderate coupling of downregulation of HOPX-β mRNA expression in DTC followed by high HOPX-β promoter methylation was observed however; high HOPX promoter methylation status was associated with the worse prognosis of DTC patients.
Rui M B Maciel, Cleber P Camacho, Lígia V M Assumpção, Natassia E Bufalo, André L Carvalho, Gisah A de Carvalho, Luciana A Castroneves, Francisco M de Castro Jr, Lucieli Ceolin, Janete M Cerutti, Rossana Corbo, Tânia M B L Ferraz, Carla V Ferreira, M Inez C França, Henrique C R Galvão, Fausto Germano-Neto, Hans Graf, Alexander A L Jorge, Ilda S Kunii, Márcio W Lauria, Vera L G Leal, Susan C Lindsey, Delmar M Lourenço Jr, Léa M Z Maciel, Patrícia K R Magalhães, João R M Martins, M Cecília Martins-Costa, Gláucia M F S Mazeto, Anelise I Impellizzeri, Célia R Nogueira, Edenir I Palmero, Cencita H C N Pessoa, Bibiana Prada, Débora R Siqueira, Maria Sharmila A Sousa, Rodrigo A Toledo, Flávia O F Valente, Fernanda Vaisman, Laura S Ward, Shana S Weber, Rita V Weiss, Ji H Yang, Magnus R Dias-da-Silva, Ana O Hoff, Sergio P A Toledo and Ana L Maia
Multiple endocrine neoplasia type 2 (MEN2) is an autosomal dominant genetic disease caused by RET gene germline mutations that is characterized by medullary thyroid carcinoma (MTC) associated with other endocrine tumors. Several reports have demonstrated that the RET mutation profile may vary according to the geographical area. In this study, we collected clinical and molecular data from 554 patients with surgically confirmed MTC from 176 families with MEN2 in 18 different Brazilian centers to compare the type and prevalence of RET mutations with those from other countries. The most frequent mutations, classified by the number of families affected, occur in codon 634, exon 11 (76 families), followed by codon 918, exon 16 (34 families: 26 with M918T and 8 with M918V) and codon 804, exon 14 (22 families: 15 with V804M and 7 with V804L). When compared with other major published series from Europe, there are several similarities and some differences. While the mutations in codons C618, C620, C630, E768 and S891 present a similar prevalence, some mutations have a lower prevalence in Brazil, and others are found mainly in Brazil (G533C and M918V). These results reflect the singular proportion of European, Amerindian and African ancestries in the Brazilian mosaic genome.