Germline alterations in many genes coding for proteins regulating DNA repair and DNA damage response (DDR) to DNA double-strand breaks (DDSB) have been recognized as pathogenic factors in hereditary cancer predisposition. The ATM-CHEK2-p53 axis has been documented as a backbone for DDR and hypothesized as a barrier against cancer initiation. However, although CHK2 kinase coded by the CHEK2 gene expedites the DDR signal, its function in activation of p53-dependent cell cycle arrest is dispensable. CHEK2 mutations rank among the most frequent germline alterations revealed by germline genetic testing for various hereditary cancer predispositions, but their interpretation is not trivial. From the perspective of interpretation of germline CHEK2 variants, we review the current knowledge related to the structure of the CHEK2 gene, the function of CHK2 kinase, and the clinical significance of CHEK2 germline mutations in patients with hereditary breast, prostate, kidney, thyroid, and colon cancers.

• Keywords
• CHEK2, CHK2, KAP1, WIP1, breast cancer, checkpoint kinase 2, colorectal cancer, germline mutation, hereditary cancer, prostate cancer, renal cancer, thyroid cancer,
• MeSH
• Checkpoint Kinase 2 chemistry   genetics   metabolism   MeSH
• Genetic Predisposition to Disease * MeSH
• Humans MeSH
• Mutation Rate MeSH
• Neoplasms enzymology   genetics   MeSH
• Substrate Specificity MeSH
• Germ-Line Mutation genetics   MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Review MeSH
• Names of Substances
• Checkpoint Kinase 2 MeSH
• CHEK2 protein, human MeSH Browser

BACKGROUND: Carriers of mutations in hereditary cancer predisposition genes represent a small but clinically important subgroup of oncology patients. The identification of causal germline mutations determines follow-up management, treatment options and genetic counselling in patients' families. Targeted next-generation sequencing-based analyses using cancer-specific panels in high-risk individuals have been rapidly adopted by diagnostic laboratories. While the use of diagnosis-specific panels is straightforward in typical cases, individuals with unusual phenotypes from families with overlapping criteria require multiple panel testing. Moreover, narrow gene panels are limited by our currently incomplete knowledge about possible genetic dispositions. METHODS: We have designed a multi-gene panel called CZECANCA (CZEch CAncer paNel for Clinical Application) for a sequencing analysis of 219 cancer-susceptibility and candidate predisposition genes associated with frequent hereditary cancers. RESULTS: The bioanalytical and bioinformatics pipeline was validated on a set of internal and commercially available DNA controls showing high coverage uniformity, sensitivity, specificity and accuracy. The panel demonstrates a reliable detection of both single nucleotide and copy number variants. Inter-laboratory, intra- and inter-run replicates confirmed the robustness of our approach. CONCLUSION: The objective of CZECANCA is a nationwide consolidation of cancer-predisposition genetic testing across various clinical indications with savings in costs, human labor and turnaround time. Moreover, the unified diagnostics will enable the integration and analysis of genotypes with associated phenotypes in a national database improving the clinical interpretation of variants.

• MeSH
• Neoplastic Syndromes, Hereditary genetics   MeSH
• Genetic Predisposition to Disease MeSH
• Genetic Association Studies MeSH
• Genetic Testing MeSH
• Humans MeSH
• INDEL Mutation MeSH
• Mutation MeSH
• Biomarkers, Tumor * MeSH
• Reproducibility of Results MeSH
• Sensitivity and Specificity MeSH
• DNA Copy Number Variations MeSH
• Computational Biology methods   MeSH
• High-Throughput Nucleotide Sequencing * methods   standards   MeSH
• Check Tag
• Humans MeSH
• Male MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Biomarkers, Tumor * MeSH

The checkpoint kinase 2 gene (CHEK2) codes for the CHK2 protein, an important mediator of the DNA damage response pathway. The CHEK2 gene has been recognized as a multi-cancer susceptibility gene; however, its role in non-Hodgkin lymphoma (NHL) remains unclear. We performed mutation analysis of the entire CHEK2 coding sequence in 340 NHL patients using denaturing high-performance liquid chromatography (DHPLC) and multiplex ligation-dependent probe amplification (MLPA). Identified hereditary variants were genotyped in 445 non-cancer controls. The influence of CHEK2 variants on disease risk was statistically evaluated. Identified CHEK2 germline variants included four truncating mutations (found in five patients and no control; P = 0.02) and nine missense variants (found in 21 patients and 12 controls; P = 0.02). Carriers of non-synonymous variants had an increased risk of NHL development [odds ratio (OR) 2.86; 95% confidence interval (CI) 1.42-5.79] and an unfavorable prognosis [hazard ratio (HR) of progression-free survival (PFS) 2.1; 95% CI 1.12-4.05]. In contrast, the most frequent intronic variant c.319+43dupA (identified in 22% of patients and 31% of controls) was associated with a decreased NHL risk (OR = 0.62; 95% CI 0.45-0.86), but its positive prognostic effect was limited to NHL patients with diffuse large B-cell lymphoma (DLBCL) treated by conventional chemotherapy without rituximab (HR-PFS 0.4; 94% CI 0.17-0.74). Our results show that germ-line CHEK2 mutations affecting protein coding sequence confer a moderately-increased risk of NHL, they are associated with an unfavorable NHL prognosis, and they may represent a valuable predictive biomarker for patients with DLBCL.

• MeSH
• Checkpoint Kinase 2 genetics   MeSH
• Adult MeSH
• Genetic Predisposition to Disease * MeSH
• Genetic Association Studies MeSH
• Middle Aged MeSH
• Humans MeSH
• Mutation MeSH
• DNA Mutational Analysis MeSH
• Lymphoma, Non-Hodgkin genetics   pathology   MeSH
• DNA Repair genetics   MeSH
• Prognosis * MeSH
• Aged, 80 and over MeSH
• Aged MeSH
• RNA Splicing genetics   MeSH
• Germ Cells MeSH
• Check Tag
• Adult MeSH
• Middle Aged MeSH
• Humans MeSH
• Male MeSH
• Aged, 80 and over MeSH
• Aged MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Checkpoint Kinase 2 MeSH
• CHEK2 protein, human MeSH Browser

Recent studies have conferred that the RAD51C and RAD51D genes, which code for the essential proteins involved in homologous recombination, are ovarian cancer (OC) susceptibility genes that may explain genetic risks in high-risk patients. We performed a mutation analysis in 171 high-risk BRCA1 and BRCA2 negative OC patients, to evaluate the frequency of hereditary RAD51C and RAD51D variants in Czech population. The analysis involved direct sequencing, high resolution melting and multiple ligation-dependent probe analysis. We identified two (1.2%) and three (1.8%) inactivating germline mutations in both respective genes, two of which (c.379_380insG, p.P127Rfs*28 in RAD51C and c.879delG, p.C294Vfs*16 in RAD51D) were novel. Interestingly, an indicative family cancer history was not present in four carriers. Moreover, the ages at the OC diagnoses in identified mutation carriers were substantially lower than those reported in previous studies (four carriers were younger than 45 years). Further, we also described rare missense variants, two in RAD51C and one in RAD51D whose clinical significance needs to be verified. Truncating mutations and rare missense variants ascertained in OC patients were not detected in 1226 control samples. Although the cumulative frequency of RAD51C and RAD51D truncating mutations in our patients was lower than that of the BRCA1 and BRCA2 genes, it may explain OC susceptibility in approximately 3% of high-risk OC patients. Therefore, an RAD51C and RAD51D analysis should be implemented into the comprehensive multi-gene testing for high-risk OC patients, including early-onset OC patients without a family cancer history.

• MeSH
• DNA-Binding Proteins genetics   MeSH
• Exons genetics   MeSH
• Genetic Predisposition to Disease * MeSH
• Genes, Neoplasm * MeSH
• Introns genetics   MeSH
• DNA, Complementary genetics   MeSH
• Humans MeSH
• Molecular Sequence Data MeSH
• DNA Mutational Analysis MeSH
• Ovarian Neoplasms genetics   MeSH
• BRCA1 Protein genetics   MeSH
• BRCA2 Protein genetics   MeSH
• Risk Factors MeSH
• Family MeSH
• Base Sequence MeSH
• Check Tag
• Humans MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Geographicals
• Czech Republic MeSH
• Names of Substances
• DNA-Binding Proteins MeSH
• DNA, Complementary MeSH
• BRCA1 Protein MeSH
• BRCA2 Protein MeSH
• RAD51C protein, human MeSH Browser
• RAD51D protein, human MeSH Browser

The DNA damage response (DDR) pathway and its core component tumor suppressor p53 block cell cycle progression after genotoxic stress and represent an intrinsic barrier preventing cancer development. The serine/threonine phosphatase PPM1D/Wip1 inactivates p53 and promotes termination of the DDR pathway. Wip1 has been suggested to act as an oncogene in a subset of tumors that retain wild-type p53. In this paper, we have identified novel gain-of-function mutations in exon 6 of PPM1D that result in expression of C-terminally truncated Wip1. Remarkably, mutations in PPM1D are present not only in the tumors but also in other tissues of breast and colorectal cancer patients, indicating that they arise early in development or affect the germline. We show that mutations in PPM1D affect the DDR pathway and propose that they could predispose to cancer.

• MeSH
• Cell Cycle MeSH
• G1 Phase * MeSH
• Genetic Predisposition to Disease MeSH
• HeLa Cells MeSH
• Humans MeSH
• MCF-7 Cells MeSH
• Mutation * MeSH
• Cell Line, Tumor MeSH
• Tumor Suppressor Protein p53 genetics   MeSH
• Neoplasms metabolism   MeSH
• DNA Damage MeSH
• Protein Phosphatase 2C MeSH
• Phosphoprotein Phosphatases genetics   physiology   MeSH
• Gene Expression Regulation, Neoplastic * MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Tumor Suppressor Protein p53 MeSH
• PPM1D protein, human MeSH Browser
• Protein Phosphatase 2C MeSH
• Phosphoprotein Phosphatases MeSH
• TP53 protein, human MeSH Browser