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37 result(s) for "Kast, Karin"
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Impact of breast cancer subtypes and patterns of metastasis on outcome
Clinical outcome of patients with stage IV breast cancer is dependent on tumor biology, extent, and localization of metastases. Routine imaging diagnostics for distant metastasis is not recommended by the national guidelines for breast cancer follow-up. In this study, we evaluated different patterns of metastases of cancer subtypes in order to generate hypotheses on individualization of follow-up after breast cancer in the adjuvant setting. Patients of the Regional Breast Cancer Center Dresden diagnosed within the years 2006–2011 were classified into the five intrinsic subtypes luminal A (ER+, Her2−, G1/2), luminal B/Her2 negative (ER+, Her2−, G3), triple positive (ER+, PR+, Her2+), Her2-enriched (ER−, Her2+), and triple negative (ER−, PR−, Her2−) and with a median follow-up of 45 months. Tumor stage at time of first diagnosis of breast cancer as well as time and site of metastasis at first diagnosis of distant metastatic disease was analyzed. Tumor specimen of 2284 female patients with primary breast cancer was classified into five subtypes. Distant recurrence-free survival at 3 years was most unfavorable in Her2-enriched (66.8 %), triple negative (75.9 %), and triple-positive breast cancer (81.7 %). The same subtypes most frequently presented with visceral metastases only at first presentation: Her2-enriched 46.9 %, triple negative 45.5 %, and triple-positive breast cancer 37.5 %. Longest median survival of 2.3 years was seen in luminal A and in Her2-enriched metastatic disease, respectively. Median survival was significantly better in the luminal A, Her2-enriched, and triple-positive subtype compared to triple-negative breast cancer ( p  < 0.005). Differences in time to metastatic disease, first localization of metastases, and overall survival after diagnosis of metastatic disease were shown. Considering new targeted therapies and the option of surgery of oligometastases, screening for visceral metastases might be reasonable after diagnosis of Her2-positive subtypes.
RPA and Rad51 constitute a cell intrinsic mechanism to protect the cytosol from self DNA
Immune recognition of cytosolic DNA represents a central antiviral defence mechanism. Within the host, short single-stranded DNA (ssDNA) continuously arises during the repair of DNA damage induced by endogenous and environmental genotoxic stress. Here we show that short ssDNA traverses the nuclear membrane, but is drawn into the nucleus by binding to the DNA replication and repair factors RPA and Rad51. Knockdown of RPA and Rad51 enhances cytosolic leakage of ssDNA resulting in cGAS-dependent type I IFN activation. Mutations in the exonuclease TREX1 cause type I IFN-dependent autoinflammation and autoimmunity. We demonstrate that TREX1 is anchored within the outer nuclear membrane to ensure immediate degradation of ssDNA leaking into the cytosol. In TREX1-deficient fibroblasts, accumulating ssDNA causes exhaustion of RPA and Rad51 resulting in replication stress and activation of p53 and type I IFN. Thus, the ssDNA-binding capacity of RPA and Rad51 constitutes a cell intrinsic mechanism to protect the cytosol from self DNA. A central antiviral defence is immune recognition of cystolic DNA. Here the authors show that RPA and RAD51, in cooperation with TREX1, function to protect the cytosol from self-DNA.
Prevalence of pathogenic BRCA1/2 germline mutations among 802 women with unilateral triple-negative breast cancer without family cancer history
Background There is no international consensus up to which age women with a diagnosis of triple-negative breast cancer (TNBC) and no family history of breast or ovarian cancer should be offered genetic testing for germline BRCA1 and BRCA2 (gBRCA) mutations. Here, we explored the association of age at TNBC diagnosis with the prevalence of pathogenic gBRCA mutations in this patient group. Methods The study comprised 802 women (median age 40 years, range 19–76) with oestrogen receptor, progesterone receptor, and human epidermal growth factor receptor type 2 negative breast cancers, who had no relatives with breast or ovarian cancer. All women were tested for pathogenic gBRCA mutations. Logistic regression analysis was used to explore the association between age at TNBC diagnosis and the presence of a pathogenic gBRCA mutation. Results A total of 127 women with TNBC (15.8%) were gBRCA mutation carriers ( BRCA1 : n  = 118, 14.7%; BRCA2 : n  = 9, 1.1%). The mutation prevalence was 32.9% in the age group 20–29 years compared to 6.9% in the age group 60–69 years. Logistic regression analysis revealed a significant increase of mutation frequency with decreasing age at diagnosis (odds ratio 1.87 per 10 year decrease, 95%CI 1.50–2.32, p  < 0.001). gBRCA mutation risk was predicted to be > 10% for women diagnosed below approximately 50 years. Conclusions Based on the general understanding that a heterozygous mutation probability of 10% or greater justifies gBRCA mutation screening, women with TNBC diagnosed before the age of 50 years and no familial history of breast and ovarian cancer should be tested for gBRCA mutations. In Germany, this would concern approximately 880 women with newly diagnosed TNBC per year, of whom approximately 150 are expected to be identified as carriers of a pathogenic gBRCA mutation.
Germline mutations in breast and ovarian cancer pedigrees establish RAD51C as a human cancer susceptibility gene
Alfons Meindl and colleagues report heterozygous germline mutations in RAD51C in families with breast and ovarian cancer. Mutations were found in 1.3% of 480 pedigrees with breast and ovarian cancer, but not in 620 pedigrees with breast cancer only. Germline mutations in a number of genes involved in the recombinational repair of DNA double-strand breaks are associated with predisposition to breast and ovarian cancer. RAD51C is essential for homologous recombination repair, and a biallelic missense mutation can cause a Fanconi anemia–like phenotype. In index cases from 1,100 German families with gynecological malignancies, we identified six monoallelic pathogenic mutations in RAD51C that confer an increased risk for breast and ovarian cancer. These include two frameshift-causing insertions, two splice-site mutations and two nonfunctional missense mutations. The mutations were found exclusively within 480 pedigrees with the occurrence of both breast and ovarian tumors (BC/OC; 1.3%) and not in 620 pedigrees with breast cancer only or in 2,912 healthy German controls. These results provide the first unambiguous evidence of highly penetrant mutations associated with human cancer in a RAD51 paralog and support the 'common disease, rare allele' hypothesis.
Targeted capture-based NGS is superior to multiplex PCR-based NGS for hereditary BRCA1 and BRCA2 gene analysis in FFPE tumor samples
Background With the introduction of Olaparib treatment for BRCA-deficient recurrent ovarian cancer, testing for somatic and/or germline mutations in BRCA1/2 genes in tumor tissues became essential for treatment decisions. In most cases only formalin-fixed paraffin-embedded (FFPE) samples, containing fragmented and chemically modified DNA of minor quality, are available. Thus, multiplex PCR-based sequencing is most commonly applied in routine molecular testing, which is predominantly focused on the identification of known hot spot mutations in oncogenes. Methods We compared the overall performance of an adjusted targeted capture-based enrichment protocol and a multiplex PCR-based approach for calling of pathogenic SNVs and InDels using DNA extracted from 13 FFPE tissue samples. We further applied both strategies to seven blood samples and five matched FFPE tumor tissues of patients with known germline exon-spanning deletions and gene-wide duplications in BRCA1/2 to evaluate CNV detection based solely on panel NGS data. Finally, we analyzed DNA from FFPE tissues of 11 index patients from families suspected of having hereditary breast and ovarian cancer, of whom no blood samples were available for testing, in order to identify underlying pathogenic germline BRCA1/2 mutations. Results The multiplex PCR-based protocol produced inhomogeneous coverage among targets of each sample and between samples as well as sporadic amplicon drop out, leading to insufficiently or non-covered nucleotides, which subsequently hindered variant detection. This protocol further led to detection of PCR-artifacts that could easily have been misinterpreted as pathogenic mutations. No such limitations were observed by application of an adjusted targeted capture-based protocol, which allowed for CNV calling with 86% sensitivity and 100% specificity. All pathogenic CNVs were confirmed in the five matched FFPE tumor samples from patients carrying known pathogenic germline mutations and we additionally identified somatic loss of the second allele in BRCA1/2 . Furthermore we detected pathogenic BRCA1/2 variants in four the eleven FFPE samples from patients of whom no blood was available for analysis. Conclusions We demonstrate that an adjusted targeted capture-based enrichment protocol is superior to commonly applied multiplex PCR-based protocols for reliable BRCA1/2 variant detection, including CNV-detection, using FFPE tumor samples.
Comparison of survival in ovarian cancer patients following treatment in certified gynecologic oncology centers and non-certified hospitals: a German retrospective cohort study (WiZen)
Background Ovarian cancer is the most lethal gynecologic cancer. This study explores differences in observed survival rates among ovarian cancer patients treated in certified versus non-certified hospitals in Germany. Methods The study used data from German statutory health insurance (SHI) funds and clinical cancer registries (CCRs), including 20,794 insured and 4,493 registry patients diagnosed with a malignant ovarian neoplasm (ICD-10-GM code C56) from 2009 to 2017. Patients were categorized based on whether they received primary treatment at hospitals certified as ovarian cancer centers by the German Cancer Society (DKG) or at non-certified hospitals. Survival analyses were conducted using Kaplan–Meier and multivariable Cox regression methods. Adjustments were performed for age, year of diagnosis, International Union Against Cancer (UICC) stage, grade, lymphatic and venous invasion, year of index treatment, distant metastasis, Elixhauser comorbidities, and hospital criteria where available in the data source used. Results After adjustment for various confounders, treatment in certified centers was associated with a lower mortality risk, corresponding to a hazard ratio (HR) of 0.883 (95% CI 0.824–0.948; p  = 0.001) in the SHI data. In the CCR data a non-significant HR of 0.964 was observed (95% CI 0.867–1.071; p  = 0.490). Among patients in the CCR cohort diagnosed with UICC stage I–III disease, receiving treatment at certified centers was associated with improved survival outcomes (HR 0.825, 95% CI 0.708–0.961; p  = 0.014). Conclusion Treatment in DKG-certified centers is associated with better survival in ovarian cancer patients, especially in earlier stages. Certification status may be a relevant factor when choosing a treatment facility. Trial registration ClinicalTrials.gov (identifier: NCT04334239). Retrospectively registered on 6 April 2020. Graphical abstract
Analysis of 30 Putative BRCA1 Splicing Mutations in Hereditary Breast and Ovarian Cancer Families Identifies Exonic Splice Site Mutations That Escape In Silico Prediction
Screening for pathogenic mutations in breast and ovarian cancer genes such as BRCA1/2, CHEK2 and RAD51C is common practice for individuals from high-risk families. However, test results may be ambiguous due to the presence of unclassified variants (UCV) in the concurrent absence of clearly cancer-predisposing mutations. Especially the presence of intronic or exonic variants within these genes that possibly affect proper pre-mRNA processing poses a challenge as their functional implications are not immediately apparent. Therefore, it appears necessary to characterize potential splicing UCV and to develop appropriate classification tools. We investigated 30 distinct BRCA1 variants, both intronic and exonic, regarding their spliceogenic potential by commonly used in silico prediction algorithms (HSF, MaxEntScan) along with in vitro transcript analyses. A total of 25 variants were identified spliceogenic, either causing/enhancing exon skipping or activation of cryptic splice sites, or both. Except from a single intronic variant causing minor effects on BRCA1 pre-mRNA processing in our analyses, 23 out of 24 intronic variants were correctly predicted by MaxEntScan, while HSF was less accurate in this cohort. Among the 6 exonic variants analyzed, 4 severely impair correct pre-mRNA processing, while the remaining two have partial effects. In contrast to the intronic alterations investigated, only half of the spliceogenic exonic variants were correctly predicted by HSF and/or MaxEntScan. These data support the idea that exonic splicing mutations are commonly disease-causing and concurrently prone to escape in silico prediction, hence necessitating experimental in vitro splicing analysis.
Identification and Functional Testing of ERCC2 Mutations in a Multi-national Cohort of Patients with Familial Breast- and Ovarian Cancer
The increasing application of gene panels for familial cancer susceptibility disorders will probably lead to an increased proposal of susceptibility gene candidates. Using ERCC2 DNA repair gene as an example, we show that proof of a possible role in cancer susceptibility requires a detailed dissection and characterization of the underlying mutations for genes with diverse cellular functions (in this case mainly DNA repair and basic cellular transcription). In case of ERCC2, panel sequencing of 1345 index cases from 587 German, 405 Lithuanian and 353 Czech families with breast and ovarian cancer (BC/OC) predisposition revealed 25 mutations (3 frameshift, 2 splice-affecting, 20 missense), all absent or very rare in the ExAC database. While 16 mutations were unique, 9 mutations showed up repeatedly with population-specific appearance. Ten out of eleven mutations that were tested exemplarily in cell-based functional assays exert diminished excision repair efficiency and/or decreased transcriptional activation capability. In order to provide evidence for BC/OC predisposition, we performed familial segregation analyses and screened ethnically matching controls. However, unlike the recently published RECQL example, none of our recurrent ERCC2 mutations showed convincing co-segregation with BC/OC or significant overrepresentation in the BC/OC cohort. Interestingly, we detected that some deleterious founder mutations had an unexpectedly high frequency of > 1% in the corresponding populations, suggesting that either homozygous carriers are not clinically recognized or homozygosity for these mutations is embryonically lethal. In conclusion, we provide a useful resource on the mutational landscape of ERCC2 mutations in hereditary BC/OC patients and, as our key finding, we demonstrate the complexity of correct interpretation for the discovery of \"bonafide\" breast cancer susceptibility genes.
Breast cancer characteristics and surgery among women with Li‐Fraumeni syndrome in Germany—A retrospective cohort study
Background Women with Li‐Fraumeni syndrome (LFS) have elevated breast cancer (BC) risk. Optimal BC treatment strategies in this population are yet unknown. Methods BC subtypes and treatment were retrospectively investigated between December 2016 and January 2019 in a multicentre study. BC risks were evaluated according to the type of surgery. Results Thirty‐five women of our study population (35/44; 79.5%) had developed 36 breast lesions at first diagnosis at a mean age of 34 years. Those breast lesions comprised 32 invasive BCs (89%), three ductal carcinoma in situ alone (8%) and one malignant phyllodes tumour (3%). BCs were mainly high‐grade (18/32), of no special type (NST; 31/32), HER2‐enriched (11/32) or luminal‐B‐(like)‐type (10/32). Affected women (n = 35) received breast‐conserving surgery (BCS, n = 17) or a mastectomy (ME, n = 18) including seven women with simultaneous contralateral prophylactic mastectomy (CPM) at first diagnosis. Nineteen women suffered 20 breast or locoregional axillary lesions at second diagnosis with mean age of 36. Median time between first and second diagnosis was 57 months; median time to contra‐ and ipsilateral recurrence depended on surgical strategies (BCS: 46 vs. unilateral ME: 93 vs. bilateral ME > 140 months). Women with a primary treatment of solitaire therapeutic ME suffered from contralateral BC earlier compared to those with therapeutic ME and CPM (median: 93 vs. >140 months). Conclusion Aggressive BC subtypes occur among women with LFS. Surgical treatment, i.e. ME and CPM, may prolong time to a second BC diagnosis. Conclusion on long‐term survival benefit is pending. Individual competing tumour risks and long‐term outcomes need to be taken into consideration. Women with Li‐Fraumeni Syndrome face challenging breast cancer risks. Therapeutic or contralateral prophylactic mastectomy can be associated with a prolonged median time to develop contralateral breast cancer.
Late onset Li-Fraumeni Syndrome with bilateral breast cancer and other malignancies: case report and review of the literature
Background Li-Fraumeni-Syndrome (LFS) is an autosomal-dominant, inherited tumour predisposition syndrome associated with heterozygous germline mutations in the TP53 gene. Patients with LFS are at a high risk to develop early-onset breast cancer and multiple malignancies, among which sarcomas are the most common. A high incidence of childhood tumours and close to 100% penetrance has been described. Knowledge of the genetic status of the TP53 gene in these patients is critical not only due to the increased risk of malignancies, but also because of the therapeutic implications, since a higher rate of radiation-induced secondary tumours in these patients has been observed. Case report We report a patient with LFS harbouring heterozygous, pathogenic TP53 germline mutation, who was affected by four synchronous malignancies at the age of 40: a myxofibrosarcoma of the right upper arm, bilateral breast cancer and a periadrenal liposarcoma. Radiological treatments and a surveillance program were adjusted according to recommendations for LFS patients. Conclusion Management of tumour treatment of patients with LFS is different to the general population because of their risk for secondary cancers in the radiation field. Screening procedures should take a possibly elevated risk for radiation induced cancer into account.