c-KIT receptor expression is strictly associated with the biological behaviour of thyroid nodules

Thyroid cancer in Ecuador: A genetic variants review and a cross-sectional population-based analysis before and after COVID-19 pandemic

Objectives

The purpose of this study is to describe the genetic variants present in the Ecuadorian population and the incidence and mortality patterns of thyroid cancer in Ecuador from 2016 to 2021.

Methods

The present research constitutes a nationwide cross-sectional study encompassing all reported cases of thyroid cancer (C-73) in Ecuador from 2016 to 2021. Incidence rates were calculated based on the annual population at risk, considering factors such as ethnicity, sex, age group, and the geographic location of the incidence. All data was collected from the Hospital Discharge Statistics and the Statistical Registry of General Deaths Databases.

Results

Between 2016 and 2021, a total of 20,297 hospital admissions and 921 deaths attributed to thyroid cancer were reported in Ecuador. The incidence of thyroid cancer remained relatively stable from 2016 to 2019. However, there was a notable decrease in 2020, followed by an increase in 2021. Notably, thyroid cancer prevalence rates were found to be higher in highlands regions. Moreover, two genetic variants, the BRAFV600E and KITL678F, have been identified in the Ecuadorian population. It is noteworthy that women exhibited a higher susceptibility to thyroid cancer, being five times more likely than men to develop this condition.

Conclusion

Ecuador exhibits one of the highest global incidences of thyroid cancer. Consequently, describing the genetic variants and epidemiological characteristics of thyroid cancer is imperative for enhancing healthcare access and formulating evidence-based public health policies. This research contributes towards a comprehensive understanding of thyroid cancer in the Ecuadorian context, aiming to improve targeted interventions and health outcomes.

c-Kit Receptors as a Therapeutic Target in Cancer: Current Insights

c-Kit is a type III receptor tyrosine kinase (RTK) that has an essential role in various biological functions including gametogenesis, melanogenesis, hematopoiesis, cell survival, and apoptosis. c-KIT aberrations, either overexpression or loss-of-function mutations, have been implicated in the pathogenesis and development of many cancers, including gastrointestinal stromal tumors, mastocytosis, acute myeloid leukemia, breast, thyroid, and colorectal cancer, making c-KIT an attractive molecular target for the treatment of cancers. Therefore, a lot of effort has been put into investigating the utility of tyrosine kinase inhibitors for the management of c-KIT mutated tumors. This review of the literature illustrates the role of c-KIT mutations in many cancers, aiming to provide insights into the role of TKIs as a therapeutic option for cancer patients with c-KIT aberrations. In conclusion, c-KIT is implicated in different types of cancer, and it could be a successful molecular target; however, proper detection of the underlying mutation type is required before starting the appropriate personalized therapy.

Identification of KIT and BRAF mutations in thyroid tissue using next-generation sequencing in an Ecuadorian patient: A case report

Background

The incidence of thyroid cancer has increased worldwide. Ecuador presents the highest incidence among Latin American countries and the second around the world. Genetic alteration is the driving force for thyroid tumorigenesis and progression. The change from valine (V) to glutamic acid (E) at codon 600 of the BRAF gene (BRAF^Val600Glu) is the most commonly reported mutation in thyroid cancer. Moreover, the BRAF mutation is not the only mutation that has been correlated with TC. For instance, mutations and overexpression of the KIT gene has been associated with different types of cancer, including lung and colon cancer, and neuroblastoma.

Case presentation

A woman in her early fifties, self-identified as mestizo, from Otavalo, Imbabura-Ecuador had no systemic diseases and denied allergies, but she had a family history of a benign thyroid nodule. Physical examination revealed a thyroid gland enlargement. The fine-needle aspiration biopsy indicated papillary thyroid cancer. The patient underwent a successful total thyroidectomy with an excellent recovery and no additional treatments after surgery. Using Next-Generation sequencing a heterozygous mutation in the BRAF gene, causing an amino acid change Val600Glu was identified. Similarly, in the KIT gene, a heterozygous mutation resulting in an amino acid change Leu678Phe was detected. Moreover, an ancestry analysis was performed, and the results showed 3.1% African, 20.9% European, and 76% Native American ancestry.

Conclusions

This report represents the genetic characteristics of papillary thyroid cancer in an Ecuadorian woman with a mainly Native American ethnic component. Further studies of pathological variants are needed to determine if the combined demographic and molecular profiles are useful to develop targeted treatments focused on the Ecuadorian population.

Galectin-3 and CD117 immunocytochemistry in the diagnosis of indeterminate thyroid lesions: A pilot study

BACKGROUND

Indeterminate thyroid lesions have always been a grey zone in the field of thyroid cytopathology. Immunocytochemistry (ICC) has emerged as a promising tool to correctly classify these indeterminate thyroid lesions into benign and malignant. Hence we planned to assess a panel of immune markers in the diagnosis of indeterminate thyroid lesions consisting of Galectin-3, considered positive for malignancy and CD117 which is positive in benign follicular epithelial cells and negative in malignant lesions.

METHODS

All the thyroid aspirates reported as indeterminate lesions over a period of 3 years were evaluated. Galectin-3 and CD117 immunocytochemistry was done in 50 alcohol fixed Pap stained smears of AUS/FLUS, FN/SFN and SM category lesions. The expression of both immune markers was assessed by semi-quantitative method and ICC score was calculated.

RESULT

Of 50 indeterminate lesions, 29 were positive for Galectin-3 and 21 were negative. CD117 was positive in 19 cases and rests 31 were negative. With the use of this ICC panel 29/30 indeterminate lesions in which histopathological correlation was available could be recategorized correctly into benign and malignant. The combined sensitivity and specificity of Galectin-3 and CD117 for categorising the indeterminate lesions into malignant category was 100%.

CONCLUSION

The combined use of positive and negative immune markers for thyroid malignancy increases the sensitivity and specificity of ICC to categorise the indeterminate thyroid lesions into benign and malignant. In cases with discordant ICC results we propose that inclusion of one additional positive and/or negative marker may resolve the diagnostic dilemma.

Validation of molecular biomarkers for preoperative diagnostics of human papillary thyroid carcinoma in fine needle aspirates

Background

Despite substantial efforts, reliable preoperative diagnostic for human thyroid malignancies in case of cytologically indeterminate nodules is still missing, resulting in high number of unnecessary thyroidectomies. In an attempt to increase precision of existing preoperative diagnostics, we aimed at validating the panel of molecular biomarkers predictive for papillary thyroid carcinoma (PTC) in preoperative fine needle aspirate (FNA) samples.

Methods

In this prospective study conducted in preoperative thyroid FNA from 44 thyroid nodules, expression levels of 11 molecular biomarkers previously validated on the postoperative samples of PTCs were measured by Cell-to-CT and QuantiGene Plex methods and correlated with final diagnosis.

Results

The QuantiGene Plex resulted in reliable gene expression measurements for FNA and core-needle biopsy (CNB) samples, however this method was less sensitive than pre-amplification based Cell-to-CT. Measurements conducted on the same samples by the two methods significantly correlated for most of the genes. Expression levels of TIMP1, c-MET and ARNTL were upregulated in PTC nodules as compared to benign counterparts, supporting previous post-operative studies. Strong correlation was observed between these biomarker alterations in the same samples. Within the sub-group of 15 indeterminate nodules (Bethesda II-V), TIMP1 had 100% specificity and 83% sensitivity for PTC cases.

Conclusions

Assessment of TIMP1, c-MET and core-clock gene ARNTL expression levels by QuantiGene Plex assay in FNA samples holds promise as an ancillary method to the cytological preoperative diagnostics.

Identification of CHEK1, SLC26A4, c-KIT, TPO and TG as new biomarkers for human follicular thyroid carcinoma

The search for preoperative biomarkers for thyroid malignancies, in particular for follicular thyroid carcinoma (FTC) diagnostics, is of utmost clinical importance. We thus aimed at screening for potential biomarker candidates for FTC. To evaluate dynamic alterations in molecular patterns as a function of thyroid malignancy progression, a comparative analysis was conducted in clinically distinct subgroups of FTC and poorly differentiated thyroid carcinoma (PDTC) nodules. NanoString analysis of FFPE samples was performed in 22 follicular adenomas, 56 FTC and 25 PDTC nodules, including oncocytic and non-oncocytic subgroups. The expression levels of CHEK1, c-KIT, SLC26A4, TG and TPO were significantly altered in all types of thyroid carcinomas. Based on collective changes of these biomarkers which correlating among each other, a predictive score has been established, allowing for discrimination between benign and FTC samples with high sensitivity and specificity. Additional transcripts related to thyroid function, cell cycle, circadian clock, and apoptosis regulation were altered in the more aggressive oncocytic subgroups only, with expression levels correlating with disease progression. Distinct molecular patterns were observed for oncocytic and non-oncocytic FTCs and PDTCs. A predictive score correlation coefficient based on collective alterations of identified here biomarkers might help to improve the preoperative diagnosis of FTC nodules.

Targeted next-generation sequencing of cancer genes in poorly differentiated thyroid cancer

Poorly differentiated thyroid carcinoma (PDTC) is a rare malignancy with higher mortality than well-differentiated thyroid carcinoma. The histological diagnosis can be difficult as well as the therapy. Improved diagnosis and new targeted therapies require knowledge of DNA sequence changes in cancer-relevant genes. The TruSeq Amplicon Cancer Panel was used to screen cancer genomes from 25 PDTC patients for somatic single-nucleotide variants in 48 genes known to represent mutational hotspots. A total of 4490 variants were found in 23 tissue samples of PDTC. Ninety-eight percent (4392) of these variants did not meet the inclusion criteria, while 98 potentially pathogenic or pathogenic variants remained after filtering. These variants were distributed over 33 genes and were all present in a heterozygous state. Five tissue samples harboured not a single variant. Predominantly, variants in P53 (43% of tissue samples) were identified, while less frequently, variants in APC, ERBB4, FLT3, KIT, SMAD4 and BRAF (each in 17% of tissue samples) as well as ATM, EGFR and FBXW7 (each in 13% of tissue samples) were observed. This study identified new potential genetic targets for further research in PDTC. Of particular interest are four observed ERBB4 (alias HER4) variants, which have not been connected to this type of thyroid carcinoma so far. In addition, APC and SMAD4 mutations have not been reported in this subtype of cancer either. In contrast to other reports, we did not find CTNNB1 variants.

Novel therapeutic clues in thyroid carcinomas: The role of targeting cancer stem cells

Thyroid carcinomas (TCs), the most common endocrine tumors, represent the eighth most common cancer diagnosed worldwide in both women and men. To treat these malignancies, several drugs are now available and a number of novel ones have been enrolling in clinical trials, addressing both oncogenic pathways in cancer cells and angiogenic pathways in tumor endothelial cells. However, their use is not devoid of serious toxicities and their efficacy is limited, being dependent on carcinoma typology and the occurrence of acquired resistance. Accordingly, it is time to recast therapeutic strategies against these types of tumors to get to newer and fully effective drugs. In this perspective, latest findings demonstrate that cancer stem cells (CSCs) represent a challenging target to strike. They possess core traits of self-renewal and differentiation, being resistant to the effects of chemotherapy and radiation and playing a key role in mediating metastasis. Therefore, basic molecular elements sustaining both development of thyroid cancer stem cells and their residence in the stemness condition represent a set of innovative and still unexplored targets to address. In this review, a thorough literature survey has been accomplished, to take stock of mechanisms governing thyroid carcinomas and to point out both their currently available treatments and the novel forthcoming ones. Pubmed, Scifinder and ClinicalTrials.gov were exploited as research applications and registry database, respectively. Original articles, reviews, and editorials published within the last ten years, as well as open clinical investigations in the field, were analyzed to suggest new exciting therapeutic opportunities for people affected by TCs.

Loss of c-KIT expression in thyroid cancer cells

Papillary thyroid carcinoma is the most frequent histologic type of thyroid tumor. Few studies investigated the role of c-KIT expression in thyroid tumors, suggesting a role for this receptor and its ligand in differentiation and growth control of thyroid epithelium and a receptor loss following malignant transformation. We investigated and correlated c-KIT expression levels and two known markers of thyrocytes differentiation, PAX8 and TTF-1, in malignant and benign cytological thyroid samples. Moreover, we performed functional studies on human papillary thyroid carcinoma cell line to associated c-KIT expression to thyrocytes differentiation and tumor proliferation. c-KIT and PAX8 expression resulted higher in benign samples compared to the malignant ones, and the expression levels of these two genes were significantly correlated to each other. We also observed that c-KIT overexpression led to an increase of PAX8 expression level together with a decrease of proliferation. Furthermore, c-KIT overexpressing cells showed a regression of typical morphological features of malignancy. Taken together these results suggest that c-KIT could be involved in the differentiation of thyroid cells and in tumor progression.

The search for preoperative biomarkers for thyroid carcinoma: application of the thyroid circadian clock properties

Accumulating evidence suggests that alterations in the molecular clocks underlying the circadian time-keeping system might be connected to changes in cell cycle, resulting in oncogenic transformation. The hypothalamic–pituitary–thyroid axis is driven by a circadian clock at several levels, with an endocrine feedback loop regulating thyroid-stimulating hormone. Changes in the expression levels of circadian and cell cycle markers may correlate with clinic-pathological characteristics in differentiated follicular thyroid carcinomas. Here we summarize recent advances in exploring complex regulation of the thyroid gland transcriptome and function by the circadian oscillator. We particularly focus on clinical implications of the parallel assessment of the circadian clock, cell-cycle and cell functionality markers in human thyroid tissue, which might help improving preoperative diagnostics of thyroid malignancies.

The combination of four molecular markers improves thyroid cancer cytologic diagnosis and patient management

Background

Papillary thyroid cancer is the most common endocrine malignancy. The most sensitive and specific diagnostic tool for thyroid nodule diagnosis is fine-needle aspiration (FNA) biopsy with cytological evaluation. Nevertheless, FNA biopsy is not always decisive leading to “indeterminate” or “suspicious” diagnoses in 10 %–30 % of cases. BRAF V600E detection is currently used as molecular test to improve the diagnosis of thyroid nodules, yet it lacks sensitivity. The aim of the present study was to identify novel molecular markers/computational models to improve the discrimination between benign and malignant thyroid lesions.

Methods

We collected 118 pre-operative thyroid FNA samples. All 118 FNA samples were characterized for the presence of the BRAF V600E mutation (exon15) by pyrosequencing and further assessed for mRNA expression of four genes (KIT, TC1, miR-222, miR-146b) by quantitative polymerase chain reaction. Computational models (Bayesian Neural Network Classifier, discriminant analysis) were built, and their ability to discriminate benign and malignant tumors were tested. Receiver operating characteristic (ROC) analysis was performed and principal component analysis was used for visualization purposes.

Results

In total, 36/70 malignant samples carried the V600E mutation, while all 48 benign samples were wild type for BRAF exon15. The Bayesian neural network (BNN) and discriminant analysis, including the mRNA expression of the four genes (KIT, TC1, miR-222, miR-146b) showed a very strong predictive value (94.12 % and 92.16 %, respectively) in discriminating malignant from benign patients. The discriminant analysis showed a correct classification of 100 % of the samples in the malignant group, and 95 % by BNN. KIT and miR-146b showed the highest diagnostic accuracy of the ROC curve, with area under the curve values of 0.973 for KIT and 0.931 for miR-146b.

Conclusions

The four genes model proposed in this study proved to be highly discriminative of the malignant status compared with BRAF assessment alone. Its implementation in clinical practice can help in identifying malignant/benign nodules that would otherwise remain suspicious.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-015-1917-2) contains supplementary material, which is available to authorized users.

Mutant-specific BRAF and CD117 immunocytochemistry potentially facilitate risk stratification for papillary thyroid carcinoma in fine-needle aspiration biopsy specimens

The study aims to test whether combination of mutant-specific BRAF and CD117 immunocytochemical (ICC) staining stratifies probability for papillary thyroid carcinoma (PTC) in thyroid fine-needle aspiration biopsy (FNAB) specimens. A consecutive cohort of cases diagnosed as atypia of undetermined significance (AUS) or suspicious for malignancy-suspicious for papillary thyroid carcinoma (SM-SPTC) from 30 December, 2011 to 23 October, 2014 in a single institute was enrolled. Forty cytologically benign and 50 cytologically diagnosed PTC within the same time span were also included. CD117 and mutant-specific BRAF (BRAF VE1) ICC staining was performed. Association of BRAF VE1 and CD117 expression with final diagnosis was analyzed. Both BRAF VE1 and CD117 showed good performance in distinguishing PTC from benign nodules. Combination of BRAF VE1 and CD117 stratified 180 cases into three categories: BRAF VE1 positive regardless of CD117 expression (ICC-malignant), BRAF VE1 negative plus low level of CD117 expression (ICC-intermediate), and BRAF VE1 negative plus high level of CD117 expression (ICC-benign), which was associated with 100, 75.6, and 0 % of malignancy. Combination of mutant-specific BRAF and CD117 ICC may potentially facilitate the PTC risk stratification in FNAB thyroid nodule specimens.

Identification of new biomarkers for human papillary thyroid carcinoma employing NanoString analysis

We previously reported an upregulation of the clock transcript BMAL1, correlating with TIMP1 expression in fresh-frozen samples from papillary thyroid carcinoma (PTC). Since frozen postoperative biopsy samples are difficult to obtain, we aimed to validate the application of high-precision NanoString analysis for formalin-fixed paraffin-embedded (FFPE) thyroid nodule samples and to screen for potential biomarkers associated with PTC. No significant differences were detected between fresh-frozen and FFPE samples. NanoString analysis of 51 transcripts in 17 PTC and 17 benign nodule samples obtained from different donors and in 24 pairs of benign and PTC nodules, obtained from the same donor (multinodular goiters), confirmed significant alterations in the levels of BMAL1, c-MET, c-KIT, TIMP1, and other transcripts. Moreover, we identified for the first time alterations in CHEK1 and BCL2 levels in PTC. A predictive score was established for each sample, based on the combined expression levels of BMAL1, CHEK1, c-MET, c-KIT and TIMP1. In combination with BRAF mutation analysis, this predictive score closely correlated with the clinicopathological characteristics of the analyzed thyroid nodules. Our study identified new thyroid transcripts with altered levels in PTC using the NanoString approach. A predictive score correlation coefficient might contribute to improve the preoperative diagnosis of thyroid nodules.

Comparison of microarray expression profiles between follicular variant of papillary thyroid carcinomas and follicular adenomas of the thyroid

Background

Follicular variant of papillary thyroid carcinoma (FVPTC) and follicular adenoma (FA) are histologically closely related tumors and differential diagnosis remains challenging. RNA expression profiling is an established method to unravel molecular mechanisms underlying the histopathology of diseases.

Methods

BRAF mutational status was established by direct sequencing the hotspot region of exon 15 in six FVPTCs and seven FAs. Whole-transcript arrays were employed to generate expression profiles in six FVPTCs, seven FAs and seven normal thyroid tissue samples. The threshold of significance for differential expression on the gene and exon level was a p-value with a false discovery rate (FDR) < 0.05 and a fold change cutoff > 2. Two dimensional average linkage hierarchical clustering was generated using differentially expressed genes. Network, pathway, and alternative splicing utilities were employed to interpret significance of expression data on the gene and exon level.

Results

Expression profiling in FVPTCs and FAs, all of which were negative for a BRAF mutation, revealed 55 transcripts that were significantly differentially expressed, 40 of which were upregulated and 15 downregulated in FVPTCs vs. FAs. Amongst the most significantly upregulated genes in FVPTCs were GABA B receptor, 2 (GABBR2), neuronal cell adhesion molecule (NRCAM), extracellular matrix protein 1 (ECM1), heparan sulfate 6-O-sulfotransferase 2 (HS6ST2), and retinoid X receptor, gamma (RXRG). The most significantly downregulated genes in FVPTCs included interaction protein for cytohesin exchange factors 1 (IPCEF1), G protein-coupled receptor 155 (GPR155), Purkinje cell protein 4 (PCP4), chondroitin sulfate N-acetylgalactosaminyltransferase 1 (CSGALNACT1), and glutamate receptor interacting protein 1 (GRIP1). Alternative splicing analysis detected 87 genes, 52 of which were also included in the list of 55 differentially expressed genes. Network analysis demonstrated multiple interactions for a number of differentially expressed molecules including vitamin D (1,25- dihydroxyvitamin D3) receptor (VDR), SMAD family member 9 (SMAD9), v-kit Hardy-Zuckerman 4 feline sarcoma viral oncogene homolog (KIT), and RXRG.

Conclusions

This is one of the first studies using whole-transcript expression arrays to compare expression profiles between FVPTCs and FAs. A set of differentially expressed genes has been identified that contains valuable candidate genes to differentiate both histopathologically related tumor types on the molecular level.

Expression profiles of microRNAs and their target genes in papillary thyroid carcinoma

The incidence of thyroid cancer has recently experienced a rapid increase in China, and papillary thyroid carcinoma (PTC) accounts for nearly 80% of human thyroid cancers. In the present study, the differential expression of microRNAs (miRNAs) and their target genes were identified in order to analyze the potential roles of miRNAs as biomarkers and in papillary thyroid carcinogenesis. One hundred and twenty-six PTC samples were collected from patients at the China-Japan Union Hospital, China, and the gene/miRNA expression profiles were examined with Illumina BeadChips and verified by real‑time RT-PCR. Gene Ontology (GO) categories were determined, and pathway analysis was carried out using KEGG. miRNA target genes were predicted by implementing three computational analysis programs: TargetScanS, DIANA-microT and PicTar. Two hundred and forty-eight miRNAs and 3,631 genes were found to be significantly deregulated (gene, P<0.05; miRNA, P<0.01) in PTC tissues when compared with their matching normal thyroid tissues. hsa-miR-206 (target gene, MET), hsa-miR-299-3p (target gene, ITGAV), hsa-miR-101 (target gene, ITGA3), hsa-miR-103 (target gene, ITGA2), hsa-miR‑222 (target genes, KIT and AXIN2), hsa-miR-15a (target genes, AXIN2 and FOXO1) and hsa-mir-221 (target gene, KIT) were identified. Together with the functions of the target genes, we further elucidated the role of miRNAs in papillary thyroid carcinogenesis and suggest the use of miRNAs as biomarkers for early diagnosis. Our findings provide the basis for future studies in the field of miRNA-based cancer therapy.

A molecular computational model improves the preoperative diagnosis of thyroid nodules

Background

Thyroid nodules with indeterminate cytological features on fine needle aspiration (FNA) cytology have a 20% risk of thyroid cancer. The aim of the current study was to determine the diagnostic utility of an 8-gene assay to distinguish benign from malignant thyroid neoplasm.

Methods

The mRNA expression level of 9 genes (KIT, SYNGR2, C21orf4, Hs.296031, DDI2, CDH1, LSM7, TC1, NATH) was analysed by quantitative PCR (q-PCR) in 93 FNA cytological samples. To evaluate the diagnostic utility of all the genes analysed, we assessed the area under the curve (AUC) for each gene individually and in combination. BRAF exon 15 status was determined by pyrosequencing. An 8-gene computational model (Neural Network Bayesian Classifier) was built and a multiple-variable analysis was then performed to assess the correlation between the markers.

Results

The AUC for each significant marker ranged between 0.625 and 0.900, thus all the significant markers, alone and in combination, can be used to distinguish between malignant and benign FNA samples. The classifier made up of KIT, CDH1, LSM7, C21orf4, DDI2, TC1, Hs.296031 and BRAF had a predictive power of 88.8%. It proved to be useful for risk stratification of the most critical cytological group of the indeterminate lesions for which there is the greatest need of accurate diagnostic markers.

Conclusion

The genetic classification obtained with this model is highly accurate at differentiating malignant from benign thyroid lesions and might be a useful adjunct in the preoperative management of patients with thyroid nodules.