The evolving role of next generation sequencing in myelodysplastic syndromes.

Myelodysplastic syndromes (MDS) are clonal haematological disorders characterized by haematopoietic cell dysplasia, peripheral blood cytopenias, and a predisposition for developing acute myeloid leukaemia (AML). Cytogenetics have historically been important in diagnosis and prognosis in MDS, but the growing accessibility of next generation sequencing (NGS) has led to growing research in the roles of molecular genetic variation on clinical decision-making in these disorders. Multiple genes have been previously studied and found to be associated with specific outcomes or disease types within MDS and knowledge of mutations in these genes provides insight into previously defined MDS subtypes. Knowledge of these mutations also informs development of novel therapies in the treatment of MDS. The precise role of NGS in the diagnosis, prognosis and monitoring of MDS remains unclear but the improvements in NGS technology and accessibility affords clinicians an additional practice tool to provide the best care for patients.

Predicting adverse events in patients undergoing hepatectomy-validation of preoperative nomogram and risk score.

BACKGROUND/PURPOSE: Much research exists on preoperative measures of postoperative mortality in the surgical treatment of liver malignancies, but little on morbidity, a more common outcome. This study aims (i) to validate the published calculations as acceptable measures of postoperative mortality and (ii) to assess the value of these published measures in predicting postoperative morbidity. METHODS: Data were collected from a prospectively managed dataset of 1059 hepatectomies performed in Louisville, Kentucky from December 1990 to April 2014. Preoperative data were used to assign scores for each of two published measures and the scores were sorted into clinically relevant groups with corresponding ordinal scores, according to the previously published literature (Dhir nomogram and Simons risk score). RESULTS: After selection, 851 hepatectomies were analyzed. Both the Dhir nomogram (p = 0.0004) and Simons risk score (p = 0.0017) were acceptable predictors of postoperative mortality. In the analysis of morbidity, Dhir scores were a poor predictor of morbidity. The Simons ordinal risk score was predictive of complications (p = 0.0029), the number of complications (p = 0.0028), complication grade (p = 0.0033), and hepatic-specific complications (p = 0.0003). CONCLUSION: The Simons ordinal risk score can be useful in assessing postoperative morbidity among hepatectomy patients.

Cost-Effective and Scalable Clonal Hematopoiesis Assay Provides Insight into Clonal Dynamics.

Clonal hematopoiesis of indeterminate potential (CHIP) is a common age-related phenomenon in which hematopoietic stem cells acquire mutations in a select set of genes commonly mutated in myeloid neoplasia which then expand clonally. Current sequencing assays to detect CHIP mutations are not optimized for the detection of these variants and can be cost-prohibitive when applied to large cohorts or to serial sequencing. In this study, an affordable (approximately US $8 per sample), accurate, and scalable sequencing assay for CHIP is introduced and validated. The efficacy of the assay was demonstrated by identifying CHIP mutations in a cohort of 456 individuals with DNA collected at multiple time points in Vanderbilt University's biobank and quantifying clonal expansion rates over time. A total of 101 individuals with CHIP/clonal cytopenia of undetermined significance were identified, and individual-level clonal expansion rate was calculated using the variant allele fraction at both time points. Differences in clonal expansion rate by driver gene were observed, but there was also significant individual-level heterogeneity, emphasizing the multifactorial nature of clonal expansion. Additionally, mutation co-occurrence and clonal competition between multiple driver mutations were explored.

Patient-specific comorbidities as prognostic variables for survival in myelofibrosis.

Treatment decisions in primary myelofibrosis (PMF) are guided by numerous prognostic systems. Patient-specific comorbidities have influence on treatment-related survival and are considered in clinical contexts but have not been routinely incorporated into current prognostic models. We hypothesized that patient-specific comorbidities would inform prognosis and could be incorporated into a quantitative score. All patients with PMF or secondary myelofibrosis with available DNA and comprehensive electronic health record (EHR) data treated at Vanderbilt University Medical Center between 1995 and 2016 were identified within Vanderbilt's Synthetic Derivative and BioVU Biobank. We recapitulated established PMF risk scores (eg, Dynamic International Prognostic Scoring System [DIPSS], DIPSS plus, Genetics-Based Prognostic Scoring System, Mutation-Enhanced International Prognostic Scoring System 70+) and comorbidities through EHR chart extraction and next-generation sequencing on biobanked peripheral blood DNA. The impact of comorbidities was assessed via DIPSS-adjusted overall survival using Bonferroni correction. Comorbidities associated with inferior survival include renal failure/dysfunction (hazard ratio [HR], 4.3; 95% confidence interval [95% CI], 2.1-8.9; P = .0001), intracranial hemorrhage (HR, 28.7; 95% CI, 7.0-116.8; P = 2.83e-06), invasive fungal infection (HR, 41.2; 95% CI, 7.2-235.2; P = 2.90e-05), and chronic encephalopathy (HR, 15.1; 95% CI, 3.8-59.4; P = .0001). The extended DIPSS model including all 4 significant comorbidities showed a significantly higher discriminating power (C-index 0.81; 95% CI, 0.78-0.84) than the original DIPSS model (C-index 0.73; 95% CI, 0.70-0.77). In summary, we repurposed an institutional biobank to identify and risk-classify an uncommon hematologic malignancy by established (eg, DIPSS) and other clinical and pathologic factors (eg, comorbidities) in an unbiased fashion. The inclusion of comorbidities into risk evaluation may augment prognostic capability of future genetics-based scoring systems.

Cost-effective and scalable clonal hematopoiesis assay provides insight into clonal dynamics.

Clonal hematopoiesis of indeterminate potential (CHIP) is a common age-related phenomenon that occurs when hematopoietic stem cells acquire mutations in a select set of genes commonly mutated in myeloid neoplasia which then expand clonally. Current sequencing assays to detect CHIP are not optimized for the detection of these variants and can be cost-prohibitive when applied to large cohorts or serial sequencing. Here, we present and validate a CHIP targeted sequencing assay that is affordable (∼$8/sample), accurate and highly scalable. To demonstrate the utility of this assay, we detected CHIP in a cohort of 456 individuals with DNA collected at multiple timepoints in the Vanderbilt BioVU biobank and quantified clonal expansion rates over time. A total of 101 individuals with CHIP were identified, and individual-level clonal expansion rate was calculated using the variant allele fraction (VAF) at both timepoints. Differences in clonal expansion rate by driver gene were observed, but there was also significant individual-level heterogeneity, emphasizing the multifactorial nature of clonal expansion. We further describe the mutation co-occurrence and clonal competition between multiple driver mutations.

High burden of clonal hematopoiesis in first responders exposed to the World Trade Center disaster.

The terrorist attacks on the World Trade Center (WTC) created an unprecedented environmental exposure to aerosolized dust, gases and potential carcinogens. Clonal hematopoiesis (CH) is defined as the acquisition of somatic mutations in blood cells and is associated with smoking and exposure to genotoxic stimuli. Here we show that deep targeted sequencing of blood samples identified a significantly higher proportion of WTC-exposed first responders with CH (10%; 48 out of 481) when compared with non-WTC-exposed firefighters (6.7%; 17 out of 255; odds ratio, 3.14; 95% confidence interval, 1.64-6.03; P = 0.0006) after controlling for age, sex and race/ethnicity. The frequency of somatic mutations in WTC-exposed first responders showed an age-related increase and predominantly affected DNMT3A, TET2 and other CH-associated genes. Exposure of lymphoblastoid cells to WTC particulate matter led to dysregulation of DNA replication at common fragile sites in vitro. Moreover, mice treated with WTC particulate matter developed an increased burden of mutations in hematopoietic stem and progenitor cell compartments. In summary, the high burden of CH in WTC-exposed first responders provides a rationale for enhanced screening and preventative efforts in this population.