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Biomedical subjects

Arleen D Auerbach

Publications and source records attributed to Arleen D Auerbach.

At least 19 recordsLinked to original sources
PubMed2020

Distinct roles of BRCA2 in replication fork protection in response to hydroxyurea and DNA interstrand cross-links.

DNA interstrand cross-links (ICLs) are a form of DNA damage that requires the interplay of a number of repair proteins including those of the Fanconi anemia (FA) and the homologous recombination (HR) pathways. Pathogenic variants in the essential gene BRCA2/FANCD1, when monoallelic, predispose to breast and ovarian cancer, and when biallelic, result in a severe subtype of Fanconi anemia. BRCA2 function in the FA pathway is attributed to its role as a mediator of the RAD51 recombinase in HR repair of programmed DNA double-strand breaks (DSB). BRCA2 and RAD51 functions are also required to protect stalled replication forks from nucleolytic degradation during response to hydroxyurea (HU). While RAD51 has been shown to be necessary in the early steps of ICL repair to prevent aberrant nuclease resection, the role of BRCA2 in this process has not been described. Here, based on the analysis of BRCA2 DNA-binding domain (DBD) mutants (c.8488-1G>A and c.8524C>T) discovered in FA patients presenting with atypical FA-like phenotypes, we establish that BRCA2 is necessary for the protection of DNA at ICLs. Cells carrying BRCA2 DBD mutations are sensitive to ICL-inducing agents but resistant to HU treatment consistent with relatively high HR repair in these cells. BRCA2 function at an ICL protects against DNA2-WRN nuclease-helicase complex and not the MRE11 nuclease that is implicated in the resection of HU-induced stalled replication forks. Our results also indicate that unlike the processing at HU-induced stalled forks, the function of the SNF2 translocases (SMARCAL1, ZRANB3, or HLTF), implicated in fork reversal, are not an integral component of the ICL repair, pointing to a different mechanism of fork protection at different DNA lesions.

BRCA2 Protein↗
PubMed2007

Chemotherapy for myeloid malignancy in children with Fanconi anemia.

BACKGROUND: Children with Fanconi anemia (FA) have a markedly increased risk of developing myeloid malignancies. Historically, patients with FA and myeloid malignancy have extremely poor outcomes. There are currently no clinical trials or case series addressing the use of chemotherapy for children with FA, except in the context of preparative regimens for stem cell transplantation (SCT). In this report we describe the toxicity of a chemotherapy approach for patients with FA and myeloid malignancy to achieve cytoreduction prior to SCT. PATIENTS AND METHODS: Four patients with FA and myelodysplastic syndrome (MDS) or acute myeloid leukemia (AML) were treated with chemotherapy (fludarabine 30 mg/m(2) and cytosine arabinoside 300 mg/m(2) each on days 2-4 and granulocyte-colony stimulating factor (G-CSF) 5 microg/kg on days 1-5), termed reduced intensity FLAG prior to SCT. RESULTS: The chemotherapy was well tolerated with expected hematologic toxicity and no measurable toxicity in other organs. Two of the three patients with AML cleared blasts from their bone marrow. Reduction in marrow cellularity was also achieved in one patient with hypercellular MDS. CONCLUSION: These data indicate that children with FA and myeloid malignancy can tolerate chemotherapy and achieve clearance of disease. It remains unclear whether pre-SCT chemotherapy improves currently poor survival rates for SCT in FA patients with myeloid malignancies and further studies are needed to determine if there is a clinical role for this strategy.

Acute Disease↗
PubMed2007

Stem cell collection and gene transfer in Fanconi anemia.

Fanconi anemia (FA) is a rare genetic syndrome characterized by progressive bone marrow failure (BMF), congenital anomalies, and a predisposition to malignancy. Successful gene transfer into hematopoietic stem cells (HSCs) could reverse BMF in this disease. We developed clinical trials to determine whether a sufficient number of CD34(+) stem cells could be collected for gene modification and to evaluate the safety and efficacy of HSC-corrective gene transfer in FA genotype A (FANCA) patients. Here, we report that FA patients have significant depletion of their BM CD34(+) cell compartment even before severe pancytopenia is present. However, oncoretroviral-mediated ex vivo gene transfer was efficient in clinical scale in FA-A cells, leading to reversal of the cellular phenotype in a significant percentage of CD34(+) cells. Re-infusion of gene-corrected products in two patients was safe and well tolerated and accompanied by transient improvements in hemoglobin and platelet counts. Gene correction was transient, likely owing to the low dose of gene-corrected cells infused. Our early experience shows that stem cell collection is well tolerated in FA patients and suggests that collection be considered as early as possible in patients who are potential candidates for future gene transfer trials.

Adolescent↗
PubMed2006

Biallelic mutations in PALB2 cause Fanconi anemia subtype FA-N and predispose to childhood cancer.

PALB2 was recently identified as a nuclear binding partner of BRCA2. Biallelic BRCA2 mutations cause Fanconi anemia subtype FA-D1 and predispose to childhood malignancies. We identified pathogenic mutations in PALB2 (also known as FANCN) in seven families affected with Fanconi anemia and cancer in early childhood, demonstrating that biallelic PALB2 mutations cause a new subtype of Fanconi anemia, FA-N, and, similar to biallelic BRCA2 mutations, confer a high risk of childhood cancer.

Alleles↗
PubMed2006

Unrelated donor bone marrow transplantation for the treatment of Fanconi anemia.

Bone marrow transplantation (BMT) is the only known cure for the hematologic manifestations of Fanconi anemia (FA). Potential benefits of unrelated donor BMT for FA, however, have been severely limited by graft rejection and treatment-related mortality with resultant poor survival. Therefore, we evaluated the impact of potential prognostic factors on hematopoietic recovery, graft-versus-host disease (GVHD), and mortality in 98 recipients of unrelated donor BMT who received transplants between 1990 and 2003. Probabilities of neutrophil (89% vs 69%; P = .02) and platelet (74% vs 23%; P < .001) recovery were higher after fludarabine-containing regimens than nonfludarabine-containing regimens. Risks of acute GVHD (relative risk [RR], 4.29; P < .001) were higher with non-T-cell-depleted grafts. The day-100 mortality rate was significantly higher after nonfludarabine-containing regimens than fludarabine-containing regimens (65% vs 24%, respectively; P < .001). Corresponding 3-year adjusted overall survival rates were 13% versus 52% (P < .001). In addition, mortality was higher in recipients who were older (> 10 years), who were cytomegalovirus (CMV) seropositive, and who received more than 20 blood product transfusions before BMT. Based on these results, significant practice changes are suggested: use of a fludarabine-containing conditioning regimen in the context of T-cell-depleted marrow allografts, and earlier referral for transplantation prior to excessive transfusions in patients with marrow failure.

Acute Disease↗
PubMed2006

Successful engraftment without radiation after fludarabine-based regimen in Fanconi anemia patients undergoing genotypically identical donor hematopoietic cell transplantation.

BACKGROUND: To potentially reduce late effects of malignancy, chronic graft-versus-host disease (GVHD), endocrinopathy, and infertility in patients with Fanconi anemia (FA) undergoing HLA-matched related donor hematopoietic cell transplantation (HCT), we developed a regimen using fludarabine (FLU), cyclophosphamide (CY), and anti-thymocyte globulin (ATG) followed by infusion of T-cell depleted (TCD) bone marrow (BM) or unmanipulated umbilical cord blood (UCB). GVHD prophylaxis consisted of cyclosporine and short course methylprednisolone. PROCEDURE: Between April 2000 and June 2003, 11 patients (10 aplastic anemia (AA), 1 myelodysplastic syndrome (MDS)) underwent HCT using this regimen. Stem cell sources were BM and UCB in eight and three patients, respectively. RESULTS: All patients demonstrated primary engraftment. Median days to neutrophil and platelet engraftment were 11 days (range 9-21) and 38 days (range 19-381), respectively. No patient developed GVHD after primary HCT. The patient with MDS relapsed with AML and a maternal donor recipient experienced secondary graft failure. For the nine FA patients with AA who underwent HLA-identical sibling donor HCT, the Kaplan-Meier estimates of overall survival and event-free survival (EFS) at 2 years are 100% and 82%, respectively, at a median follow-up of 2.9 years (range 1.9-4.8). CONCLUSIONS: In summary, a FLU-based, non-irradiation approach is effective for FA patients with AA undergoing HLA-identical sibling donor HCT.

Adolescent↗
PubMed2005

The BRCA1-interacting helicase BRIP1 is deficient in Fanconi anemia.

Seven Fanconi anemia-associated proteins (FANCA, FANCB, FANCC, FANCE, FANCF, FANCG and FANCL) form a nuclear Fanconi anemia core complex that activates the monoubiquitination of FANCD2, targeting FANCD2 to BRCA1-containing nuclear foci. Cells from individuals with Fanconi anemia of complementation groups D1 and J (FA-D1 and FA-J) have normal FANCD2 ubiquitination. Using genetic mapping, mutation identification and western-blot data, we identify the defective protein in FA-J cells as BRIP1 (also called BACH1), a DNA helicase that is a binding partner of the breast cancer tumor suppressor BRCA1.

Blotting, Western↗
PubMed2005

A rapid method for retrovirus-mediated identification of complementation groups in Fanconi anemia patients.

Fanconi anemia (FA) is a rare autosomal recessive disorder that results from mutations in at least 11 different genes. Recent studies have demonstrated that clinical progression of the disease may be influenced by inter- and intragenic variations, emphasizing the importance of identifying the complementation groups. In the present study we have employed bicistronic retrovirus vectors that coexpress FA-specific cDNAs for complementation groups A, C, F, and G, together with the enhanced green fluorescence protein (EGFP), allowing for specific analysis of transduced EGFP+ cells within bulk cultures by flow cytometry. In addition, the assay relies on the correction of the characteristic FA-associated G2/M arrest after treatment of cells with DNA-damaging agents, which is analyzed by flow cytometry. Results obtained with this assay matched the complementation groups known for 12 control lymphoblast cell lines tested. We report here the results obtained for 48 FA patients with unknown complementation groups using this new assay. Complementation groups were identified for 24 patients. We have identified mutations in the genes corresponding to the assigned complementation group in 23 samples. This assay has now been established in a standardized fashion for complementation assignments in FA patients and the subsequent directing of rapid mutation analysis in those patients.

Cell Line↗
PubMed2005

Spectrum of sequence variations in the FANCA gene: an International Fanconi Anemia Registry (IFAR) study.

Fanconi anemia (FA) is an autosomal recessive disorder that is defined by cellular hypersensitivity to DNA cross-linking agents, and is characterized clinically by developmental abnormalities, progressive bone-marrow failure, and predisposition to leukemia and solid tumors. There is extensive genetic heterogeneity, with at least 11 different FA complementation groups. FA-A is the most common group, accounting for approximately 65% of all affected individuals. The mutation spectrum of the FANCA gene, located on chromosome 16q24.3, is highly heterogeneous. Here we summarize all sequence variations (mutations and polymorphisms) in FANCA described in the literature and listed in the Fanconi Anemia Mutation Database as of March 2004, and report 61 novel FANCA mutations identified in FA patients registered in the International Fanconi Anemia Registry (IFAR). Thirty-eight novel SNPs, previously unreported in the literature or in dbSNP, were also identified. We studied the segregation of common FANCA SNPs in FA families to generate haplotypes. We found that FANCA SNP data are highly useful for carrier testing, prenatal diagnosis, and preimplantation genetic diagnosis, particularly when the disease-causing mutations are unknown. Twenty-two large genomic deletions were identified by detection of apparent homozygosity for rare SNPs. In addition, a conserved SNP haplotype block spanning at least 60 kb of the FANCA gene was identified in individuals from various ethnic groups.

Amino Acid Substitution↗
PubMed2005

GST genotype may modify clinical phenotype in patients with Fanconi anaemia.

In the search for genetic modifiers of the Fanconi anaemia (FA) phenotype, we examined the role of polymorphism in three glutathione s-transferase genes (GSTT1, GSTM1 and GSTP1) in 356 FA patients enrolled in the International Fanconi Anaemia Registry (IFAR). Cellular sensitivity to 1,2:3,4 diepoxybutane was significantly increased in GSTT1 deleted compared with GSTT1 positive cases (median chromosomal breaks 11.1 vs. 8.3, P < 0.01) but there was no effect on clinical manifestations of FA. GSTM1 genotype significantly influenced time to bone marrow failure in complementation group FA-C, (median age 3.0 years vs. 7.0 years, P < 0.01). GSTP1 genotype did not influence FA phenotype.

Fanconi Anemia↗
PubMed2004

Germline mutations in BRCA2: shared genetic susceptibility to breast cancer, early onset leukemia, and Fanconi anemia.

The breast cancer susceptibility gene BRCA2 has recently been identified as identical to the Fanconi anemia (FA) gene FANCD1. Here we expand the clinical implications of this discovery. Notably, we identified 6 children in 5 kindreds exhibiting the co-occurrence of BRCA2 mutations, FA, and early onset acute leukemia. Leukemia occurred at a median of 2.2 years of age in the BRCA2 patients in contrast to a median onset of 13.4 years in all other FA patients in the International Fanconi Anemia Registry (IFAR; P <.0001). Breast cancer was noted in 4 of the 5 kindreds. Of the 6 children with leukemia, 4 were treated with bone marrow transplantation and 2 are alive at 3 and 9 months after treatment. Our results suggest that BRCA2 testing should be considered in all patients with FA in whom the complementation group cannot be defined or in whom leukemia is diagnosed at or before 5 years of age.

Acute Disease↗
PubMed2004

Successful umbilical cord blood transplantation for Fanconi anemia using preimplantation genetic diagnosis for HLA-matched donor.

Fanconi anemia is a rare autosomal recessive disease characterized by bone marrow failure, developmental anomalies, and a high incidence of myelodysplasia and acute myeloid leukemia. Stem cell transplantation is the only curative treatment. In the absence of matched- sibling donor, an alternative mismatched family or matched unrelated donor can be used, but the results are inferior to the matched-sibling transplant and carry a high risk of morbidity and mortality. Preimplantation genetic diagnosis (PGD) has been increasingly used in recent years for mutation analysis for many genetic disorders and results in the birth of healthy children, saving the need for the termination of pregnancy of an affected embryo. The use of PGD for combined analysis of mutation and HLA-matching was reported for the first time in 2001. This enables the birth of an unaffected child who can serve as a donor for an affected sibling in need for stem cell transplantation. We report successful cord blood transplantation for a Fanconi anemia patient from his HLA-matched sibling, born after PGD that included mutation analysis for Fanconi anemia and HLA typing. PGD can provide an unaffected donor for a sibling affected by genetic disease in the absence of a compatible related donor.

Blood Donors↗
PubMed2004

Fanconi anemia in Ashkenazi Jews.

Fanconi anemia (FA) should be included among the genetic diseases that occur at high frequency in the Ashkenazi Jewish population. FA exhibits extensive genetic heterogeneity; there are currently 11 complementation groups reported, and 8 (i.e., FANCA, FANCC, FANCD1/BRCA2, FANCD2, FANCE, FANCF, FANCG, and FANCL) genes have been isolated. While patients may be from widely diverse ethnic groups, a single mutation in complementation group FA-C, c.711 + 4A > T (commonly known as IVS4 + 4A > T prior to current nomenclature rules) is unique to FA patients of Ashkenazi Jewish ancestry, and has a carrier frequency of greater than 1/100 in this population. In addition, a mutation (c.65G > A) in FANCA (FA-A is the most common complementation group in non-Jewish patients) and the mutation c.6174delT in FANCD1/BRCA2 are also unique to the Ashkenazi Jewish population. Therefore, the study of Fanconi anemia can lend insight into the types of cancer-predisposing genetic diseases specific to the Ashkenazi.

Child↗
PubMed2004

Fatal hemorrhage from androgen-related hepatic adenoma after hematopoietic cell transplantation.

Fanconi anemia is a rare genetic disorder that leads to bone marrow failure. Hematopoietic cell transplantation (HCT) is currently the only treatment option with curative potential. When a suitable HLA-matched sibling donor is not available, patients are often treated with androgenic steroids before considering HCT. Such androgen treatments can lead to the development of hepatic adenomas, which usually regress upon stopping androgen therapy. A patient with Fanconi anemia is described who underwent an unrelated umbilical cord blood transplant with a history of a hepatic adenoma related to androgen therapy. No adenomas were detected on an ultrasound examination prior to HCT. Soon after HCT, he died due to sudden rupture and hemorrhage of a hepatic adenoma. This case illustrates the need for extra vigilance in the detection and management of hepatic adenomas in patients treated with androgens, especially prior to HCT.

Adenoma↗
PubMed2003

Human papillomavirus DNA and p53 polymorphisms in squamous cell carcinomas from Fanconi anemia patients.

Fanconi anemia is an autosomal recessive disorder characterized by congenital malformations, bone marrow failure, and the development of squamous cell carcinomas (SCCs) and other cancers. Recent clinicopathologic evidence has raised the possibility that an environmental factor such as human papillomavirus (HPV) may be involved in the pathogenesis of SCCs in Fanconi anemia patients. Given the high prevalence of p53 mutations in SCCs among the general population and the lack of p53 mutations in HPV-related carcinogenesis, we evaluated the role of HPV and p53 mutations and polymorphisms in SCC from Fanconi anemia patients. We used polymerase chain reaction (PCR) screening and real-time PCR to detect and quantify HPV DNA in DNA extracted from microdissected SCCs obtained from 24 Fanconi anemia patients (n = 25 SCCs; case subjects) and 50 age-, sex-, and tumor site-matched SCC patients without Fanconi anemia (n = 50 SCCs; control subjects). We PCR-amplified and sequenced exons 4-9 of the p53 gene from SCC DNA. We detected HPV DNA in 84% of the SCC specimens from the case subjects and in 36% of the SCC specimens from the control subjects (P<.001). The prevalence of p53 mutations in SCCs from the case subjects (0%, 0/25) was statistically significantly lower than that of SCCs from the control subjects (36%, 12/33; P<.001). A greater proportion of patients with Fanconi anemia and SCC were homozygous for Arg72, a p53 polymorphism that may be associated with increased risk for HPV-associated human malignancies, than an ethnically-matched cohort of Fanconi anemia patients without SCC (75% versus 51%; P =.05). These data suggest that Fanconi anemia is associated with increased susceptibility to HPV-induced carcinogenesis.

Carcinoma, Squamous Cell↗
PubMed2003

Shared genetic susceptibility to breast cancer, brain tumors, and Fanconi anemia.

Fanconi anemia is an inherited disease characterized by bone marrow failure, congenital malformations, and predisposition to cancer. The breast cancer susceptibility gene BRCA2 was recently found to be associated with Fanconi anemia complementation group D1 (FA-D1). We examined four kindreds afflicted with Fanconi anemia for the presence of germline BRCA2 mutations. One kindred, of Ashkenazi Jewish ancestry, had five members who were diagnosed with breast cancer and two cousins who were BRCA2*6174delT/C3069X compound heterozygotes and had Fanconi anemia and brain tumors. In another kindred of Ashkenazi Jewish and Lithuanian Catholic ancestry, a child with Fanconi anemia and a medulloblastoma was a BRCA2*6174delT/886delGT compound heterozygote. Two other kindreds each contained a Fanconi anemia-afflicted child who developed medulloblastoma; one child was of Latin American ancestry and a compound heterozygote for BRCA2*I2490T/ 5301insA and the other was African American and a compound heterozygote for BRCA2*Q3066X/E1308X. Median age of the Fanconi anemia-afflicted children at brain tumor diagnosis was 3.5 years. The co-occurrence of brain tumors, Fanconi anemia, and breast cancer observed in one of these kindreds constitutes a new syndromic association. Individuals who carry a germline BRCA2 mutation and who plan to have children with a partner of Ashkenazi Jewish descent should consider undergoing genetic counseling.

Alleles↗
PubMed2003

High incidence of head and neck squamous cell carcinoma in patients with Fanconi anemia.

BACKGROUND: Fanconi anemia (FA) is a rare autosomal recessive disorder characterized by a high degree of genomic instability and predisposition to cancer development. Recent evidence suggests that the incidence of head and neck squamous cell carcinoma (HNSCC) may be increased in patients with FA. OBJECTIVE: To determine the cumulative incidence, tumor distribution, and outcome of HNSCC in patients with FA. DESIGN AND SETTING: We analyzed data from 754 subjects from the International Fanconi Anemia Registry, a prospectively collected database of patients with FA. MAIN OUTCOME MEASURES: Cumulative incidence of HNSCC and 2-year overall, relapse-free and disease-specific survival. RESULTS: Of the 754 patients in the International Fanconi Anemia Registry, 19 (3%) had HNSCC. This is a significantly higher incidence of HNSCC compared with that observed in the general population (standardized incidence ratio, 500; 95% confidence interval, 300-781) (P<.001). The patients' age ranged from 15 to 49 years (median, 31 years), and there was a 2:1 female predominance. Surgical treatment was well tolerated (n = 17); however, radiation therapy and chemotherapy were associated with significant morbidity and mortality. Of the 19 patients, 10 (53%) developed locoregional recurrences within a median of 16 months from diagnosis. The median follow-up was 29 months. The 2-year disease-specific, overall, and relapse-free survival rates were 49%, 49%, and 42%, respectively. The cumulative incidence of relapse by the age of 40 years was 50%. CONCLUSIONS: In patients with FA, there is a high incidence of aggressive HNSCC at a young age. Surgery remains the mainstay of treatment because patients with FA tolerate radiation therapy and chemotherapy poorly, with significant morbidity. An increased understanding of FA-associated malignancies is not only important in the clinical management of patients with FA but can also elucidate the role of chromosomal instability in the development of HNSCC in general.

Adolescent↗