bims-lifras Biomed News
on Li-Fraumeni syndrome
Issue of 2023–04–02
thirteen papers selected by
Joanna Zawacka-Pankau, Karolinska Institutet



  1. Cancers (Basel). 2023 Mar 20. pii: 1852. [Epub ahead of print]15(6):
      We investigate the prevalence of germline mutations in cancer predisposition genes in patients with pancreatic ductal adenocarcinoma (PDAC) or suspected related hereditary syndromes.
    METHODS: we enrolled for NGS with an Illumina TrueSight Cancer panel comprising 19 CPGs and 113 consecutive subjects referred to cancer genetic clinics for metastatic PDAC, early onset PDAC, suspected hereditary syndrome, or positive family history.
    RESULTS: Overall, 23 (20.1%) subjects were carriers of 24 pathogenetic variants (PVs). We found 9 variants in BRCA2 (37.5%), 6 in CDKN2A (25%), 3 in ATM (12.5%), 2 in BRCA1 (8.3%), 1 in CHEK2 (4.1%), 1 in PALB2 (4.1%), 1 in MITF (4.1%), and 1 in FANCM (4.1%). A double PV (BRCA1 plus BRCA2) was found in 1 subject. We observed a nearly 30% (16/55) mutational rate in the subgroup of subjects tested for the suspected syndromes (PDAC and other synchronous or metachronous tumors or an indicative family history), and the frequency was significantly higher than that in patients with only metastatic PDAC (p = 0.05). In our cohort, 39 variants of unknown significance (VUS) were identified, most of which (16/39, 41%) in genes belonging to the Lynch syndrome spectrum.
    CONCLUSION: A clinically relevant proportion of pancreatic cancer is associated with mutations in known predisposition genes. Guidelines instructing on an adequate selection for accessing genetic testing are eagerly needed. The heterogeneity of mutations identified in this study reinforces the value of using a multiple-gene panel in pancreatic cancer.
    Keywords:  cancer predisposition; germline mutation; hereditary syndrome; pancreatic cancer; pathogenic variant
    DOI:  https://doi.org/10.3390/cancers15061852
  2. Eur J Cancer Prev. 2023 Mar 27.
      The common use of genetic testing has reinvigorated discussions surrounding enhanced cancer surveillance, chemoprevention, and preventive surgery strategies due to increasing recognition of pathogenic germline genetic variants. Prophylactic surgery for hereditary cancer syndromes can significantly reduce the risk of developing cancer. Hereditary diffuse gastric cancer (HDGC), characterized by high penetrance and an autosomal dominant inheritance pattern, is causally linked to germline mutations in the CDH1tumor suppressor gene. Risk-reducing total gastrectomy is currently recommended in patients with pathogenic and likely pathogenic CDH1 variants; however, the physical and psychosocial sequelae of complete stomach removal are substantial and need to be investigated further. In this review, we address the risks and benefits of prophylactic total gastrectomy for HDGC in the context of prophylactic surgery for other highly penetrant cancer syndromes.
    DOI:  https://doi.org/10.1097/CEJ.0000000000000798
  3. Cancer Med. 2023 Mar 31.
       BACKGROUND: Approximately 90% of pancreatic ductal adenocarcinoma (PDAC) cases are driven by the untargetable non-G12C KRAS mutations, and only a small subset of patients are eligible for FDA-approved precision therapies. The practice of precision therapy in pancreatic cancer was limited by the paucity of targetable genetic alterations, especially in the Asian population.
    METHODS: To explore therapeutic targets in 499 Chinese PDAC patients, a deep sequencing panel (OncoPanscan™, Genetron health) was used to characterize somatic alterations including point mutations, indels, copy number alterations, gene fusions as well as pathogenic germline variants.
    RESULTS: We performed genomic profiling in 499 Chinese PDAC patients, which revealed somatic driver mutations in KRAS, TP53, CDKN2A, SMAD4, ARID1A, RNF43, and pathogenic germline variants (PGVs) in cancer predisposition genes including BRCA2, PALB2, and ATM. Overall, 20.4% of patients had targetable genomic alterations. About 8.4% of patients carried inactivating germline and somatic variants in BRCA1/2 and PALB2, which were susceptible to platinum and PARP inhibitors therapy. Patients with KRAS wild-type disease and early-onset pancreatic cancer (EOPC) harbored actionable mutations including BRAF, EGFR, ERBB2, and MAP2K1/2. Compared to PGV-negative patients, PGV-positive patients were younger and more likely to have a family history of cancer. Furthermore, PGVs in PALB2, BRCA2, and ATM were associated with high PDAC risk in the Chinese population.
    CONCLUSIONS: Our results demonstrated that a genetic screen of actionable genomic variants could facilitate precision therapy and cancer risk reduction in pancreatic cancer patients of Asian ethnicity.
    Keywords:  cancer risk; genetic alterations; next-generation sequencing; pancreatic cancer; precision therapy
    DOI:  https://doi.org/10.1002/cam4.5871
  4. Mol Genet Genomic Med. 2023 Mar 28. e2170
       BACKGROUND: Genetic testing for pancreatic ductal adenocarcinoma (PDAC) patients is in constant development. However, the status of homologous recombination repair (HRR) genes in unselected Chinese PDAC has not been fully explored. This study aims to characterize the profile of germline mutations in HRR genes in Chinese PDAC patients.
    METHODS: A cohort of 256 PDAC patients were enrolled at Zhongshan Hospital Fudan University between 2019 and 2021. Germline DNA was analyzed by next-generation sequencing using a multigene panel of the 21 HRR genes.
    RESULTS: The germline pathogenic (P)/likely pathogenic (LP) variant rates were 7.0% (18/256) in unselected patients with pancreatic cancer. Among them, 1.6% (4/256) were identified as harboring BRCA2 variants, and 5.5% (14/256) patients carried non-BRCA variants. Variants were detected in eight non-BRCA genes, including ATM (4, 1.6%), PALB2 (4, 1.6%), ATR (1, 0.4%), BRIP1 (1, 0.4%), CHEK2 (1, 0.4%), MRE11 (1, 0.4%), PTEN (1, 0.4%), and STK11 (1, 0.4%). ATM, BRCA2, and PALB2 were the most prevalent variant genes. If only BRCA1/2 was tested, 5.5% of P/LP variants would have been lost. Further, we found that the landscape of P/LP HRR variants in various population cohorts was quite different. However, no significant difference was found in clinical characteristics between germline HRR P/LP carriers and non-carriers. In our study, one case carrying a germline PALB2 variant showed a long-time response to platinum-based chemotherapy and PARP inhibitor.
    CONCLUSION: This study comprehensively depicts the prevalence and characteristics of germline HRR mutations in unselected Chinese PDAC patients. Our findings show the clinical utility of a multigene panel may increase the detection of P/LP HRR carriers.
    Keywords:  germline mutations; homologous recombination; next-generation sequencing; pancreatic ductal adenocarcinoma
    DOI:  https://doi.org/10.1002/mgg3.2170
  5. Ophthalmic Genet. 2023 Mar 27. 1-9
       PURPOSE: To report the genotype and phenotype of a cohort of unselected uveal melanoma (UM) patients who had germline multi-gene panel genetic testing, including the BAP1 gene, from a large multi-ethnic cancer centre. We describe the central role of the medical genetics clinic in collaboration with oncologists in a mainstreaming model to facilitate genetic testing, counselling and streamlining of patients with hereditary cancer predisposition.
    METHODS: A retrospective chart review of clinical and genetic findings of unselected UM patients who had germline genetic testing between December 2019 and October 2021 was conducted. Extracted DNA from peripheral blood samples were analyzed with a multi-gene panel that included at least six genes associated with hereditary melanoma. The correlation between the genotype and the phenotype of the cohort was evaluated. Statistical analysis comprised descriptive and comparative statistics with significance assigned at p < .05. The genetics clinic streamlined patients among the relevant oncology clinics for cancer screening in germline BAP1 positive individuals.
    RESULTS: In unselected UM patients, 3.5% (4/114) tested positive for a BAP1 pathogenic variant. Germline BAP1 status was associated with a family history of mesothelioma (p = .0015) and metastatic disease (p = .017). There were no other significant associations between the patient- or tumour-related characteristics and germline BAP1 results.
    CONCLUSION: A germline BAP1 mutation was detected in 3.5% of unselected UM patients. The oncologist-initiated and genetics-led mainstreaming model is a straightforward process and can be utilized for offering genetic testing to all UM patients.
    Keywords:  BAP1; Uveal melanoma; genetic counselling; hereditary cancer; mainstreaming; service delivery
    DOI:  https://doi.org/10.1080/13816810.2023.2191707
  6. Genes (Basel). 2023 Mar 18. pii: 744. [Epub ahead of print]14(3):
       BACKGROUND: HLRCC syndrome is a hereditary cancer predisposition syndrome caused by heterozygous germline pathogenic variant of the fumarate hydratase (FH) gene and characterized by cutaneous leiomyomas (CL), uterine leiomyomas (UL), and renal cell carcinoma (RCC). Loss of function variant of FH gene inactivates the Kreb's cycle enzyme activity and predisposes individuals with such variant to the development of HLRCC.
    METHODS: Next-generation sequencing (NGS) and Sanger confirmation were given to family members accessible. Following that, a functional study in vitro was performed to further confirm the pathogenicity of the variant. FH-Wild type (FH-WT) and FH-mutant (FH-MUT) (E378K) plasmid were constructed and transfected into 293T and uterine leiomyoma cell lines, respectively. Proliferation assessment was executed to show how this mutation affects the growth of uterine leiomyoma. qPCR and Western blotting were performed to investigate the change of transcription and translation of FH with mutation (E378K), and FH enzyme assay activity were tested in 293T cells with mutation and wild-type plasmids.
    RESULTS: Here, we presented two families with the same missense variant (c.1132G > A) that has not been reported as a germline mutation in hereditary uterine leiomyomas before and classified as VUS in gene databases. Our in vitro experiments supported the pathogenicity of this missense variant, especially in uterine leiomyomata.
    CONCLUSIONS: According to the American College of Medical Genetics (ACMG) guideline, the E378K variant was classified as likely pathogenic (with evidence PS4_support, PS3_support, PM2_support, PP1, PP3 and PP4 evidence). Further insights into clinical management in uterine leiomyomata were discussed and should be practiced in gynecological clinical settings.
    Keywords:  clinical management in hereditary gynecological disease; fumarate hydratase (FH) gene; hereditary leiomyomatosis and renal cell cancer syndrome (HLRCC); in vitro functional study
    DOI:  https://doi.org/10.3390/genes14030744
  7. Clin Genet. 2023 Mar 27.
      In breast or ovarian cancer (BC/OC) patients with evocative personal and/or family history, multigene panel sequencing is performed on blood to diagnose hereditary predispositions. Additionally, BRCA1/BRCA2 testing can be performed on tumor sample for therapeutic purpose. The accuracy of multigene panel tumor analysis on BC/OC to detect predisposing germline pathogenic variants (gPV) has not been precisely assessed. By comparing sequencing data from blood and fresh-frozen tumor we show that tumor genomic instability causes pitfalls to consider when performing tumor testing to detect gPV. Even if loss of heterozygosity increases germline signal in most cases, somatic copy number variants (CNV) can mask germline CNV and collapse point gPV variant allele frequency (VAF). Moreover, VAF does not allow an accurate distinction between germline and somatic pathogenic variants.
    Keywords:  HBOC; MSH6; PARPi; RAD51C; TP53
    DOI:  https://doi.org/10.1111/cge.14327
  8. Lancet Oncol. 2023 Apr;pii: S1470-2045(23)00057-8. [Epub ahead of print]24(4): 383-391
       BACKGROUND: Loss of function variants in CDH1 are the most frequent cause of hereditary diffuse gastric cancer. Endoscopy is regarded as insufficient for early detection due to the infiltrative phenotype of diffuse-type cancers. Microscopic foci of invasive signet ring cells are pathognomonic of CDH1 and precede development of diffuse gastric cancer. We aimed to assess the safety and effectiveness of endoscopy for cancer interception in individuals with germline CDH1 variants, particularly in those who declined prophylactic total gastrectomy.
    METHODS: In this prospective cohort study, we included asymptomatic patients aged 2 years or older with pathogenic or likely pathogenic germline CDH1 variants who underwent endoscopic screening and surveillance at the National Institutes of Health (Bethesda, MD, USA) as part of a natural history study of hereditary gastric cancers (NCT03030404). Endoscopy was done with non-targeted biopsies and one or more targeted biopsy and assessment of focal lesions. Endoscopy findings, pathological data, personal and family cancer history, and demographics were recorded. Procedural morbidity, gastric cancer detection by endoscopy and gastrectomy, and cancer-specific events were assessed. Screening was defined as the initial endoscopy and all subsequent endoscopies were considered surveillance; follow-up endoscopy was at 6 to 12 months. The primary aim was to determine effectiveness of endoscopic surveillance for detection of gastric signet ring cell carcinoma.
    FINDINGS: Between Jan 25, 2017, and Dec 12, 2021, 270 patients (median age 46·6 years [IQR 36·5-59·8], 173 [64%] female participants, 97 [36%] male participants; 250 [93%] were non-Hispanic White, eight [3%] were multiracial, four [2%] were non-Hispanic Black, three [1%] were Hispanic, two [1%] were Asian, and one [<1%] was American Indian or Alaskan Native) with germline CDH1 variants were screened, in whom 467 endoscopies were done as of data cutoff (April 30, 2022). 213 (79%) of 270 patients had a family history of gastric cancer, and 176 (65%) reported a family history of breast cancer. Median follow-up was 31·1 months (IQR 17·1-42·1). 38 803 total gastric biopsy samples were obtained, of which 1163 (3%) were positive for invasive signet ring cell carcinoma. Signet ring cell carcinoma was detected in 76 (63%) of 120 patients who had two or more surveillance endoscopies, of whom 74 had occult cancer detected; the remaining two individuals developed focal ulcerations each corresponding to pT3N0 stage carcinoma. 98 (36%) of 270 patients proceeded to prophylactic total gastrectomy. Among patients who had a prophylactic total gastrectomy after an endoscopy with biopsy samples negative for cancer (42 [43%] of 98), multifocal stage IA gastric carcinoma was detected in 39 (93%). Two (1%) participants died during follow-up, one due to metastatic lobular breast cancer and the other due to underlying cerebrovascular disease, and no participants were diagnosed with advanced stage (III or IV) cancer during follow-up.
    INTERPRETATION: In our cohort, endoscopic cancer surveillance was an acceptable alternative to surgery in individuals with CDH1 variants who declined total gastrectomy. The low rate of incident tumours (>T1a) suggests that surveillance might be a rational alternative to surgery in individuals with CDH1 variants.
    FUNDING: Intramural Research Program, National Institutes of Health.
    DOI:  https://doi.org/10.1016/S1470-2045(23)00057-8
  9. Genes (Basel). 2023 Mar 09. pii: 684. [Epub ahead of print]14(3):
      Hereditary cancer syndromes are inherited disorders caused by germline pathogenic variants (PVs) that lead to an increased risk of developing certain types of cancer, frequently at an earlier age than in the rest of the population. The germline PVs promote cancer development, growth and survival, and may represent an ideal target for the personalized treatment of hereditary tumors. PARP inhibitors for the treatment of BRCA and PALB2-associated tumors, immune checkpoint inhibitors for tumors associated with the Lynch Syndrome, HIF-2α inhibitor in the VHL-related cancers and, finally, selective RET inhibitors for the treatment of MEN2-associated medullary thyroid cancer are the most successful examples of how a germline PVs can be exploited to develop effective personalized therapies and improve the outcome of these patients. The present review aims to describe and discuss the personalized systemic therapies for inherited cancer syndromes that have been developed and investigated in clinical trials in recent decades.
    Keywords:  BRCA; MMR/MSI; PALB2; RET; VHL; hereditary cancer syndromes; personalized therapy
    DOI:  https://doi.org/10.3390/genes14030684
  10. Cancer Res Commun. 2023 Mar;3(3): 483-488
      Many studies have shown that the distributions of the genomic, nucleotide, and epigenetic contexts of somatic variants in tumors are informative of cancer etiology. Recently, a new direction of research has focused on extracting signals from the contexts of germline variants and evidence has emerged that patterns defined by these factors are associated with oncogenic pathways, histologic subtypes, and prognosis. It remains an open question whether aggregating germline variants using meta-features capturing their genomic, nucleotide, and epigenetic contexts can improve cancer risk prediction. This aggregation approach can potentially increase statistical power for detecting signals from rare variants, which have been hypothesized to be a major source of the missing heritability of cancer. Using germline whole-exome sequencing data from the UK Biobank, we developed risk models for 10 cancer types using known risk variants (cancer-associated SNPs and pathogenic variants in known cancer predisposition genes) as well as models that additionally include the meta-features. The meta-features did not improve the prediction accuracy of models based on known risk variants. It is possible that expanding the approach to whole-genome sequencing can lead to gains in prediction accuracy.
    Significance: There is evidence that cancer is partly caused by rare genetic variants that have not yet been identified. We investigate this issue using novel statistical methods and data from the UK Biobank.
    DOI:  https://doi.org/10.1158/2767-9764.CRC-22-0355
  11. Front Oncol. 2023 ;13 1066083
      The pathogenesis of acute leukemia is still complex and vague. Most types of acute leukemia are related to somatic gene mutations, and familial incidence is rare. Here we report a case of familial leukemia. The proband presented to our hospital with vaginal bleeding and disseminated intravascular coagulation at the age of 42 and was diagnosed with acute promyelocytic leukemia with typical PML-RARα fusion gene caused by t(15;17)(q24;q21) translocation. By taking the history, we found that the patient's second daughter had been diagnosed with B-cell acute leukemia with ETV6-RUNX1 fusion gene at age 6. Then we performed whole exome sequencing in peripheral blood mononuclear cells from these two patients at remission status and identified 8 shared germline gene mutations. Using functional annotation and Sanger sequencing validation, we finally focused on a single nucleotide variant in RecQ like helicase (RECQL), rs146924988, which was negative in the proband's healthy eldest daughter. This gene variant potentially led to a relative lack of RECQL protein, disordered DNA repair and chromatin rearrangement, which may mediate the occurrence of fusion genes, as driving factors for leukemia. This study identified a novel possible leukemia-related germline gene variant and provided a new understanding for the screening and pathogenesis of hereditary predisposition syndromes.
    Keywords:  acute leukemia; case report; fusion gene; germline mutation; hereditary predisposition
    DOI:  https://doi.org/10.3389/fonc.2023.1066083
  12. Breast Cancer Res Treat. 2023 Mar 31.
       PURPOSE: Cancers deficient in homologous recombination DNA repair, such as those with BRCA1 or BRCA2 (BRCA1/2) mutations rely on a pathway mediated by the enzyme poly(adenosine diphosphate-ribose) polymerase (PARP). PARP inhibitors (PARPi's) have demonstrated efficacy in treating patients with germline (g)BRCA1/2, somatic (s)BRCA1/2, and gPALB2 mutations in clinical trials. However, patients with a poor performance status (PS) and those with severe organ impairment are often excluded from clinical trials and cancer-directed treatment.
    METHODS: We report the cases of two patients with metastatic breast cancer who had poor PS, significant visceral disease, and gPALB2 and sBRCA mutations, who derived significant clinical benefit from treatment with PARP inhibition.
    RESULTS: Patient A had germline testing demonstrating a heterozygous PALB2 pathogenic mutation (c.3323delA) and a BRCA2 variant of unknown significance (c.9353T>C), and tumor sequencing revealed PALB2 (c.228_229del and c.3323del) and ESR1 (c.1610A>C) mutations. Patient B was negative for pathologic BRCA mutations upon germline testing, but tumor sequencing demonstrated somatic BRCA2 copy number loss and a PIK3CA mutation (c.1633G>A). Treatment with PARPi's in these two patients with an initial PS of 3-4 and significant visceral disease resulted in prolonged clinical benefit.
    CONCLUSION: Patients with a poor PS, such as those described here, may still have meaningful clinical responses to cancer treatments targeting oncogenic drivers. More studies evaluating PARPi's beyond gBRCA1/2 mutations and in sub-optimal PS would help identify patients who may benefit from these therapies.
    Keywords:  BRCA; Breast cancer; PALB2; PARP; Performance status
    DOI:  https://doi.org/10.1007/s10549-023-06910-6
  13. Sci Rep. 2023 Mar 31. 13(1): 5307
      Population-based estimates of pathogenic variation burden in gynecologic cancer predisposition genes are a prerequisite for the development of effective precision public health strategies. This study aims to reveal the burden of pathogenic variants in a comprehensive set of clinically relevant breast, ovarian, and endometrial cancer genes in a large population-based study. We performed a rigorous manual classification procedure to identify pathogenic variants in a panel of 17 gynecologic cancer predisposition genes in a cohort of 7091 individuals, representing 0.35% of the general population. The population burden of pathogenic variants in hereditary gynecologic cancer-related genes in our study was 2.14%. Pathogenic variants in genes ATM, BRCA1, and CDH1 are significantly enriched and the burden of pathogenic variants in CHEK2 is decreased in our population compared to the control population. We have identified a high burden of pathogenic variants in several gynecologic cancer-related genes in the Slovenian population, most importantly in the BRCA1 gene.
    DOI:  https://doi.org/10.1038/s41598-023-32397-8