Fanconi Anaemia, Childhood Cancer and the BRCA Genes

The heterogeneous cancer phenotype of individuals with biallelic germline pathogenic variants in CHEK2

PURPOSE

Females with biallelic CHEK2 germline pathogenic variants (gPVs) more often develop multiple breast cancers than individuals with monoallelic CHEK2 gPVs. This study is aimed at expanding the knowledge on the occurrence of other malignancies.

METHODS

Exome sequencing of individuals who developed multiple primary malignancies identified 3 individuals with the CHEK2 (NM_007194.4) c.1100del p.(Thr367MetfsTer15) loss-of-function gPV in a biallelic state. We collected the phenotypes of an additional cohort of individuals with CHEK2 biallelic gPVs (n = 291).

RESULTS

In total, 157 individuals (53.4%; 157/294 individuals) developed ≥1 (pre)malignancy. The most common (pre)malignancies next to breast cancer were colorectal- (n = 19), thyroid- (n = 19), and prostate (pre)malignancies (n = 12). Females with biallelic CHEK2 loss-of-function gPVs more frequently developed ≥2 (pre)malignancies and at an earlier age compared with females biallelic for the CHEK2 c.470T>C p.(Ile157Thr) missense variant. Furthermore, 26 males (31%; 26/84 males) with CHEK2 biallelic gPVs developed ≥1 (pre)malignancies of 15 origins.

CONCLUSION

Our study suggests that CHEK2 biallelic gPVs likely increase the susceptibility to develop multiple malignancies in various tissues, both in females and males. However, it is possible that a substantial proportion of individuals with CHEK2 biallelic gPVs is missed as diagnostic testing for CHEK2 often is limited to individuals who developed breast cancer.

Cancer genetic counselling for hereditary breast cancer in the era of precision oncology

A relevant percentage of breast cancers (BCs) are tied to pathogenetic (P)/likely pathogenetic (LP) variants in predisposing genes. The knowledge of P/LP variants is an essential element in the management of BC patients since the first diagnosis because it influences surgery and subsequent oncological treatments and follow-up. Moreover, patients with metastatic BCs can benefit from personalized treatment if carriers of P/LP in BRCA1/2 genes. Multigene panels allow the identification of other predisposing genes with an impact on management. Cascade genetic testing for healthy family members allows personalized preventive strategies. Here, we review the advances and the challenges of Cancer Genetic Counseling (CGC). We focus on the area of oncology directed to hereditary BC management describing the peculiar way to lead CGC and how CGC changes over time. The authors describe the impact of genetic testing by targeted approach or universal approach on the management of BC according to the stage at diagnosis. Moreover, they describe the burden of CGC and testing and future perspectives to widely offer testing. A new perspective is needed for models of service delivery of CGC and testing, beyond formal genetic counselling. A broader genetic test can be quickly usable in clinical practice for comprehensive BC management and personalized prevention in the era of precision oncology.

Recurrent BRCA2 exon 3 deletion in Assyrian families

We identified six patients from five families with a recurrent mutation: NM_000059.3 (BRCA2) exon 3 deletion. All families self-identified as Assyrian. Assyrians are an ethnoreligious population of ancient Mesopotamia, now mostly living in modern day Iraq, Syria, Turkey and Iran. They are historically a socially isolated population with intermarriage within their community, living as a religious and language minority in mostly Muslim countries. The probands of each family presented with a classic BRCA2-associated cancer including early-onset breast cancer, epithelial serous ovarian cancer, male breast cancer and/or high-grade prostate cancer, and family history that was also significant for BRCA2-associated cancer. BRCA2 exon 3 deletion is classified as pathogenic and has been previously described in the literature, but it has not been described as a founder mutation in a particular population. We characterise this recurrent BRCA2 pathogenic variant in five Assyrian families in a single centre cohort.

Germline Variants and Characteristic Features of Hereditary Hematological Malignancy Syndrome

Due to the proliferation of genetic testing, pathogenic germline variants predisposing to hereditary hematological malignancy syndrome (HHMS) have been identified in an increasing number of genes. Consequently, the field of HHMS is gaining recognition among clinicians and scientists worldwide. Patients with germline genetic abnormalities often have poor outcomes and are candidates for allogeneic hematopoietic stem cell transplantation (HSCT). However, HSCT using blood from a related donor should be carefully considered because of the risk that the patient may inherit a pathogenic variant. At present, we now face the challenge of incorporating these advances into clinical practice for patients with myelodysplastic syndrome (MDS) or acute myeloid leukemia (AML) and optimizing the management and surveillance of patients and asymptomatic carriers, with the limitation that evidence-based guidelines are often inadequate. The 2016 revision of the WHO classification added a new section on myeloid malignant neoplasms, including MDS and AML with germline predisposition. The main syndromes can be classified into three groups. Those without pre-existing disease or organ dysfunction; DDX41, TP53, CEBPA, those with pre-existing platelet disorders; ANKRD26, ETV6, RUNX1, and those with other organ dysfunctions; SAMD9/SAMD9L, GATA2, and inherited bone marrow failure syndromes. In this review, we will outline the role of the genes involved in HHMS in order to clarify our understanding of HHMS.

Simultaneous Occurrence of Multiple Neoplasms in Children with Cancer Predisposition Syndromes: Collaborating with Abnormal Genes

The identification of cancer predisposition syndromes (CPSs) plays a crucial role in understanding the etiology of pediatric cancers. CPSs are genetic mutations that increase the risk of developing cancer at an earlier age compared to the risk for the general population. This article aims to provide a comprehensive analysis of three unique cases involving pediatric patients with CPS who were diagnosed with multiple simultaneous or metachronous cancers. The first case involves a child with embryonal rhabdomyosarcoma, nephroblastoma, glioma, and subsequent medulloblastoma. Genetic analysis identified two pathogenic variants in the BRCA2 gene. The second case involves a child with alveolar rhabdomyosarcoma, juvenile xanthogranuloma, gliomas, and subsequent JMML/MDS/MPS. A pathogenic variant in the NF1 gene was identified. The third case involves a child with pleuropulmonary blastoma and pediatric cystic nephroma/nephroblastoma, in whom a pathogenic variant in the DICER1 gene was identified. Multiple simultaneous and metachronous cancers in pediatric patients with CPSs are a rare but significant phenomenon. Comprehensive analysis and genetic testing play significant roles in understanding the underlying mechanisms and guiding treatment strategies for these unique cases. Early detection and targeted interventions are important for improving outcomes in these individuals.

Case Report: Clinical benefit from multi-target tyrosine kinase inhibitor and PARP inhibitor in a patient with cancer of unknown primary with BRCA1 large genomic rearrangement

Background: Cancer of unknown primary (CUP), which accounts for 3%-5% of new cancer cases every year, involves the presence of a type of histologically confirmed metastatic tumors whose primary site cannot be confirmed by conventional diagnostic methods. This difficulty in identifying the primary site means that CUP patients fail to receive precisely targeted therapy. Most patients are treated with empiric chemotherapy, with a median survival of 6 months and even poorer prognosis within an unfavorable subset of CUP. Case report: An 80-year-old woman presented with masses in the abdomen. Following comprehensive imagological and immunohistochemical examinations, she was diagnosed with CUP. She emphatically declined chemotherapy; thus, anlotinib has been administered with patient consent since 02/07/2019, and stable disease (SD) was observed for 2 years. During subsequent treatment, a large genomic rearrangement in BRCA1 was identified in the patient via NGS, and SD was observed for a further 6 months following olaparib treatment. The type of LGR identified in this patient was discovered to be BRCA1 exon 17-18 inversion (inv), which has never been previously reported. Conclusion: For CUP patients, a chemo-free regimen seems to be acceptable as a first-line treatment, and NGS-guided targeted treatment could improve patient outcomes.

Molecular-Targeted Therapy for Tumor-Agnostic Mutations in Acute Myeloid Leukemia

Comprehensive genomic profiling examinations (CGPs) have recently been developed, and a variety of tumor-agnostic mutations have been detected, leading to the development of new molecular-targetable therapies across solid tumors. In addition, the elucidation of hereditary tumors, such as breast and ovarian cancer, has pioneered a new age marked by the development of new treatments and lifetime management strategies required for patients with potential or presented hereditary cancers. In acute myeloid leukemia (AML), however, few tumor-agnostic or hereditary mutations have been the focus of investigation, with associated molecular-targeted therapies remaining poorly developed. We focused on representative tumor-agnostic mutations such as the TP53, KIT, KRAS, BRCA1, ATM, JAK2, NTRK3, FGFR3 and EGFR genes, referring to a CGP study conducted in Japan, and we considered the possibility of developing molecular-targeted therapies for AML with tumor-agnostic mutations. We summarized the frequency, the prognosis, the structure and the function of these mutations as well as the current treatment strategies in solid tumors, revealed the genetical relationships between solid tumors and AML and developed tumor-agnostic molecular-targeted therapies and lifetime management strategies in AML.

Interdisciplinary risk counseling for hereditary breast and ovarian cancer: real-world data from a specialized center

Purpose

Hereditary breast and ovarian cancer has long been established to affect a considerable number of patients and their families. By identifying those at risk ideally before they have been diagnosed with breast and/or ovarian cancer, access to preventive measures, intensified screening and special therapeutic options can be obtained, and thus, prognosis can be altered beneficially. Therefore, a standardized screening and counseling process has been established in Germany under the aegis of the German Consortium for Hereditary Breast and Ovarian Cancer (GC-HBOC). As one of these specialized clinics, the HBOC-Center at Charité offers genetic counseling as well as genetic analysis based on the GC-HBOC standards. This analysis aims first at depicting this process from screening through counseling to genetic analysis as well as the patient collective and second at correlating the results of genetic analysis performed. Thus, real-world data from an HBOC-Center with a substantial patient collective and a high frequency of pathogenic variants in various genes shall be presented.

Methods

The data of 2531 people having been counseled at the HBOC-Center at Charité in 2016 and 2017 were analyzed in terms of patient and family history as well as pathogenic variants detected during genetic analysis with the TruRisk® gene panel when genetic analysis was conducted. This standardized analysis is compiled and regularly adjusted by the GC-HBOC. The following genes were included at time of research: BRCA1, BRCA2, ATM, CDH1, CHEK2, PALB2, RAD51C, RAD51D, NBN, and TP53.

Results

Genetic analysis was conducted in 59.8% of all cases meeting the criteria for genetic analysis and 286 pathogenic variants were detected among 278 (30.3%) counselees tested using the TruRisk® gene panel. These were primarily found in the genes BRCA1 (44.8%) and BRCA2 (28.3%) but also in CHEK2 (12.2%), ATM (5.6%) and PALB2 (3.5%). The highest prevalence of pathogenic variants was seen among the families with both ovarian and breast cancer (50.5%), followed by families with ovarian cancer only (43.2%) and families with breast cancer only (35.6%)—these differences are statistically significant (p < 0.001). Considering breast cancer subtypes, the highest rate of pathogenic variants was detected among patients with triple-negative breast cancer (40.7%) and among patients who had had been diagnosed with triple-negative breast cancer before the age of 40 (53.4%)—both observations proved to be statistically significant (p = 0.003 and p = 0.001).

Conclusion

Genetic counseling and analysis provide the foundation in the prevention and therapy of hereditary breast and ovarian cancer. The rate of pathogenic variants detected is associated with family history as well as breast cancer subtype and age at diagnosis, and can reach considerable dimensions. Therefore, a standardized process of identification, genetic counseling and genetic analysis deems mandatory.

Fanconi Anemia Pathway in Colorectal Cancer: A Novel Opportunity for Diagnosis, Prognosis and Therapy

Colorectal cancer (CRC) is the third most commonly diagnosed malignancy and has the second highest mortality rate globally. Thanks to the advent of next-generation sequencing technologies, several novel candidate genes have been proposed for CRC susceptibility. Germline biallelic mutations in one or more of the 22 currently recognized Fanconi anemia (FA) genes have been associated with Fanconi anemia disease, while germline monoallelic mutations, somatic mutations, or the promoter hypermethylation of some FANC genes increases the risk of cancer development, including CRC. The FA pathway is a substantial part of the DNA damage response system that participates in the repair of DNA inter-strand crosslinks through homologous recombination (HR) and protects genome stability via replication fork stabilization, respectively. Recent studies revealed associations between FA gene/protein tumor expression levels (i.e., FANC genes) and CRC progression and drug resistance. Moreover, the FA pathway represents a potential target in the CRC treatment. In fact, FANC gene characteristics may contribute to chemosensitize tumor cells to DNA crosslinking agents such as oxaliplatin and cisplatin besides exploiting the synthetic lethal approach for selective targeting of tumor cells. Hence, this review summarizes the current knowledge on the function of the FA pathway in DNA repair and genomic integrity with a focus on the FANC genes as potential predisposition factors to CRC. We then introduce recent literature that highlights the importance of FANC genes in CRC as promising prognostic and predictive biomarkers for disease management and treatment. Finally, we represent a brief overview of the current knowledge around the FANC genes as synthetic lethal therapeutic targets for precision cancer medicine.