Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P43146 (tumour suppressor)
 5,935 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The DNA damage checkpoint kinase, CHK2, promotes growth arrest or apoptosis through phosphorylating targets such as Cdc25A, Cdc25C, BRCA1, and p53. Both germline and somatic loss-of-function CHEK2 mutations occur in human tumours, the former linked to the Li-Fraumeni syndrome, and the latter found in diverse types of sporadic malignancies. Here we examined the status of CHK2 by genetic and immunohistochemical analyses in 53 breast carcinomas previously characterized for TP53 status. We identified two CHEK2 mutants, 470T>C (Ile157Thr), and a novel mutation, 1368insA leading to a premature stop codon in exon 13. The truncated protein encoded by CHEK2 carrying the 1368insA was stable yet mislocalized to the cytoplasm in tumour sections and when ectopically expressed in cultured cells. Unexpectedly, we found CHEK2 to be subject to extensive alternative splicing, with some 90 splice variants detected in our tumour series. While all cancers expressed normal-length CHEK2 mRNA together with the spliced transcripts, we demonstrate and/or predict some of these splice variants to lack CHK2 function and/or localize aberrantly. We conclude that cytoplasmic sequestration may represent a novel mechanism to disable CHK2, and propose to further explore the significance of the complex splicing patterns of this tumour suppressor gene in oncogenesis.
 ...
PMID:Alternative splicing and mutation status of CHEK2 in stage III breast cancer. 1536 33

Hereditary cancer syndromes are frequently seen in young cancer patients and patients with a positive family history. Genetic testing is important for the identification of high-risk individuals, and for the early introduction of specialized preventive care or prophylactic surgeries. High-risk tumour suppressor genes (BRCA1 and BRCA2) and DNA repair genes (MLH1, MSH2 and MSH6) are responsible for a substantial part of hereditary breast, ovarian and colorectal cancer. Other hereditary cancers are seen less frequently, but genetic testing has increased for many other site-specific cancers and complex syndromes. Genetic centres and molecular genetic laboratories are located mostly within university or regional hospitals. Some genetic centres are private. It is highly recommended (Czech Society for Medical Genetics) that all laboratories are accredited according to ISO 15,189 and that genetic testing of hereditary cancer syndromes is indicated by medical geneticists. The indication criteria and prevention strategies were published in Supplement 22 of Clinical Oncology 2009 (in Czech). Preventive care for high-risk individuals is organized by thirteen Oncology Centres, which provide most of the oncology care in the Czech Republic. Genetic testing and preventive care for high-risk individuals and mutation carriers is covered by health insurance. The molecular genetic laboratory at the MMCI provides molecular genetic testing of BRCA1, BRCA2, CHEK2 for hereditary breast/ovarian cancer, MLH1, MSH2, MSH6 for Lynch syndrome,TP53 for Li-Fraumeni syndrome, CDKN2A for familial malignant melanoma syndrome and CDH1 gene for hereditary diffuse gastric cancer. Other syndromes are tested in specialized laboratories elsewhere.The use of genetic testing is increasing because of more frequent referrals from oncologists and other specialists and the increasing variety of genes tested. However, in some patients the testing is not recommended and other family members are dying because of the late diagnosis of hereditary syndrome. Greater awareness of the importance of genetic testing in oncology is needed.
 ...
PMID:Genetic testing and prevention of hereditary cancer at the MMCI--over 10 years of experience. 2134 12

The treatment landscape for metastatic melanoma has been revolutionised by the introduction of immunotherapy and targeted therapies. Despite these advances, some patients exhibit primary or acquired resistance to treatment. We present the case of a resected mucosal melanoma that on relapse underwent transformation to a dedifferentiated state. The relapsed tumour was phenotypically disparate and demonstrated loss of all typical melanoma-associated immunohistochemical markers. Furthermore, it demonstrated aggressive biological behaviour and immunotherapy resistance. We performed genomic profiling of the original and relapsed tumour to further elucidate the mechanisms underlying this rare phenomenon. Mass spectrometry-based single-nucleotide polymorphism genotyping technology was used to screen for mutations in the original and recurrent tumour. Whole-exome sequencing was performed on the original tumour, recurrent tumour and blood. Both the original and recurrent tumour shared a NRAS mutation, a similar aneuploidy profile and proportion of somatic single-nucleotide variants. However, in contrast to the original tumour, the recurrent tumour demonstrated a lower mutational burden and deletions in the CDKN2A/CDKN2B and CHEK2 genes. The genomic similarity between the original and recurrent tumour attests to a common ancestry and the possible existence of nongenomic drivers inciting phenotype plasticity. In contrast, the low mutational load and potential inactivation of tumour suppressor genes in the recurrent tumour may underlie its rapid proliferative rate and immunoresistance. Dynamic treatment models are desired in the future to track the genomic and epigenetic evolution of a tumour to guide optimal therapy choice and sequencing.
 ...
PMID:Genomic profiling of a dedifferentiated mucosal melanoma following exposure to immunotherapy. 3142 81

The CHEK2 gene is mostly considered as a moderate breast cancer gene with the result that many clinicians have a narrow focus. We present the 10-year journey of a man who had five different cancers and had iterative genetic testing including for Li-Fraumeni syndrome, eventually to discover a pathogenic variant in the CHEK2 gene, possibly explaining his numerous cancers. This diagnosis offered him closure which he had desperately sought for well over a decade. A pathogenic variant in the CHEK2 gene can potentially explain these cancers because of its function as a tumour suppressor gene. Consideration is warranted of what this means for individuals with CHEK2 variants who may develop multiple cancers, their prognosis and whether different treatment modalities such as chemotherapy, radiotherapy or target agents would need modification. We encourage more research into the many faces of the CHEK2 gene and the potential for predisposition to multiple cancers.
 ...
PMID:Is CHEK2 a moderate-risk breast cancer gene or the younger sister of Li-Fraumeni? 3290 Jul 38