Related Experiment Video
Updated: Jul 2, 2025
Targeted Next-generation Sequencing and Bioinformatics Pipeline to Evaluate Genetic Determinants of Constitutional Disease
Published on: April 4, 2018
CHEK2 germline variants identified in familial nonmedullary thyroid cancer lead to impaired protein structure and
Carolina Pires1, Inês J Marques1, Mariana Valério2
1Unidade de Investigação em Patobiologia Molecular, Instituto Português de Oncologia de Lisboa Francisco Gentil, Lisboa, Portugal; NOVA Medical School/Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Lisboa, Portugal.
Abstract:
Approximately 5 to 15% of nonmedullary thyroid cancers (NMTC) present in a familial form (familial nonmedullary thyroid cancers [FNMTC]). The genetic basis of FNMTC remains largely unknown, representing a limitation for diagnostic and clinical management. Recently, germline mutations in DNA repair-related genes have been described in cases with thyroid cancer (TC), suggesting a role in FNMTC etiology. Here, two FNMTC families were studied, each with two members affected with TC. Ninety-four hereditary cancer predisposition genes were analyzed through next-generation sequencing, revealing two germline CHEK2 missense variants (c.962A > C, p.E321A and c.470T > C, p.I157T), which segregated with TC in each FNMTC family. p.E321A, located in the CHK2 protein kinase domain, is a rare variant, previously unreported in the literature. Conversely, p.I157T, located in CHK2 forkhead-associated domain, has been extensively described, having conflicting interpretations of pathogenicity. CHK2 proteins (WT and variants) were characterized using biophysical methods, molecular dynamics simulations, and immunohistochemistry. Overall, biophysical characterization of these CHK2 variants showed that they have compromised structural and conformational stability and impaired kinase activity, compared to the WT protein. CHK2 appears to aggregate into amyloid-like fibrils in vitro, which opens future perspectives toward positioning CHK2 in cancer pathophysiology. CHK2 variants exhibited higher propensity for this conformational change, also displaying higher expression in thyroid tumors. The present findings support the utility of complementary biophysical and in silico approaches toward understanding the impact of genetic variants in protein structure and function, improving the current knowledge on CHEK2 variants' role in FNMTC genetic basis, with prospective clinical translation.
Insights
Genetic variants in the CHEK2 gene were identified in familial nonmedullary thyroid cancer (FNMTC) families. These CHEK2 variants show impaired function and increased aggregation, suggesting a role in FNMTC development.
Area of Science:
- Genetics
- Molecular Biology
- Oncology
Background:
- Familial nonmedullary thyroid cancer (FNMTC) accounts for 5-15% of thyroid cancers, but its genetic basis is largely unknown.
- Germline mutations in DNA repair genes are increasingly implicated in thyroid cancer (TC) etiology.
- Understanding FNMTC genetics is crucial for improved diagnostics and clinical management.
Purpose of the Study:
- To investigate the genetic underpinnings of FNMTC in two affected families.
- To identify and characterize novel or known germline variants in hereditary cancer predisposition genes.
- To elucidate the functional impact of identified variants on protein structure and activity.
Main Methods:
- Next-generation sequencing of 94 hereditary cancer predisposition genes.
- Segregation analysis of identified variants within FNMTC families.
- Biophysical characterization, molecular dynamics simulations, and immunohistochemistry of CHEK2 protein variants.
Main Results:
- Two germline CHEK2 missense variants (p.E321A and p.I157T) were identified and segregated with TC in both families.
- Both CHEK2 variants demonstrated compromised structural stability, impaired kinase activity, and increased propensity for amyloid-like fibril formation in vitro.
- CHEK2 variants showed higher expression levels in thyroid tumors compared to wild-type.
Conclusions:
- The identified CHEK2 variants contribute to the genetic basis of FNMTC.
- Biophysical and in silico methods are valuable for assessing the pathogenicity of genetic variants.
- Findings offer insights into CHEK2's role in thyroid cancer pathophysiology and potential clinical applications.
Related Concept Videos
01:12Loss of Tumor Suppressor Gene Functions
When the tumor suppressor genes develop mutations or are lost, cells start growing out of control, leading to cancer. However, a single functional copy of the tumor suppressor gene is enough for the cells to maintain their normal functions and cell...
01:38Nucleotide Excision Repair
Cells are regularly exposed to mutagens—factors in the environment that can damage DNA and generate mutations. UV radiation is one of the most common mutagens and is estimated to introduce a significant number of changes in DNA. These include bends or kinks in the structure, which can block DNA replication or transcription. If these errors are not fixed, the damage can cause mutations, which in turn can result in cancer or disease depending on which sequences are...
01:29Protein Folding Quality Check in the RER
01:39Mutations
01:20The Retinoblastoma Gene
The first-ever tumor suppressor gene called Rb was identified in retinoblastoma - a rare eye tumor in children. In inherited forms of the disease, a child inherits one defective copy of the Rb gene, which predisposes them to retinoblastoma. However,...
02:23Abnormal Proliferation