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result(s) for
"Silk, Mikhail T."
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The impact of genetic heterogeneity on biomarker development in kidney cancer assessed by multiregional sampling
by
Russo, Paul
,
Sankin, Alexander
,
Ostrovnaya, Irina
in
Biomarker
,
Biomarkers
,
Biomarkers, Tumor - genetics
2014
Primary clear cell renal cell carcinoma (ccRCC) genetic heterogeneity may lead to an underestimation of the mutational burden detected from a single site evaluation. We sought to characterize the extent of clonal branching involving key tumor suppressor mutations in primary ccRCC and determine if genetic heterogeneity could limit the mutation profiling from a single region assessment. Ex vivo core needle biopsies were obtained from three to five different regions of resected renal tumors at a single institution from 2012 to 2013. DNA was extracted and targeted sequencing was performed on five genes associated with ccRCC (von‐Hippel Lindau [VHL], PBRM1, SETD2, BAP1, and KDM5C). We constructed phylogenetic trees by inferring clonal evolution based on the mutations present within each core and estimated the predictive power of detecting a mutation for each successive tumor region sampled. We obtained 47 ex vivo biopsy cores from 14 primary ccRCC's (median tumor size 4.5 cm, IQR 4.0–5.9 cm). Branching patterns of various complexities were observed in tumors with three or more mutations. A VHL mutation was detected in nine tumors (64%), each time being present ubiquitously throughout the tumor. Other genes had various degrees of regional mutational variation. Based on the mutations' prevalence we estimated that three different tumor regions should be sampled to detect mutations in PBRM1, SETD2, BAP1, and/or KDM5C with 90% certainty. The mutational burden of renal tumors varies by region sampled. Single site assessment of key tumor suppressor mutations in primary ccRCC may not adequately capture the genetic predictors of tumor behavior. Single region genomics of primary kidney cancer leads to underestimation of critical tumor suppressor mutations. On average, analysis of a combination of four distinct tumor regions will yield ~90% of accuracy in detecting the detrimental 3p TSG mutations of clear cell renal cell carcinoma.
Journal Article
Spectroscopy and Machine Learning Based Rapid Point-of-Care Assessment of Core Needle Cancer Biopsies
by
Rekhtman, Natasha
,
Solomon, Stephen B
,
Ostroverkhov, Victor
in
Artificial intelligence
,
Bioinformatics
,
Biopsy
2019
Solid tumor needle biopsies are essential to confirm malignancy and assess for actionable characteristics or genetic alterations to guide treatment selection. Ensuring that sufficient and suitable material is acquired for tumor profiling, while minimizing patient risk, remains a critical unmet need. Here, we evaluated the performance characteristics of transmission optical spectroscopy for rapid identification of malignant tissue in core needle biopsies (CNB). Human kidney biopsy specimens (545 CNB from 102 patients, 5583 spectra for analysis) were analyzed directly on core biopsy needles with a custom-built optical spectroscopy instrument. Machine learning classifiers were trained to differentiate malignant from normal tissue spectra. Classifiers were compared using receiver operating characteristics analysis and sensitivity and specificity were calculated relative to a histopathologic gold standard. The best performing algorithm was the random forest (sensitivity 96% and 93%, specificity 90% and 93% at the level of individual spectra and full CNB, respectively). Ex-vivo spectroscopy paired with machine learning paves the way towards rapid and accurate characterization of CNB at the time of tissue acquisition and improving tumor biopsy quality.
Monitoring Incidence of COVID-19 Cases, Hospitalizations, and Deaths, by Vaccination Status — 13 U.S. Jurisdictions, April 4–July 17, 2021
by
Meyer, Stephanie
,
Scobie, Heather M.
,
Pogosjans, Sargis
in
Age groups
,
Complications and side effects
,
Coronaviruses
2021
What is already known about this topic? The incidence of SARS-CoV-2 infection, hospitalization, and death is higher in unvaccinated than vaccinated persons, and the incidence rate ratios are related to vaccine effectiveness. What is added by this report? Across 13 U.S. jurisdictions, incidence rate ratios for hospitalization and death changed relatively little after the SARS-CoV-2 B.1.617.2 (Delta) variant reached predominance, suggesting high, continued vaccine effectiveness against severe COVID-19. Case IRRs decreased, suggesting reduced vaccine effectiveness for prevention of SARS-CoV-2 infections. What are the implications for public health practice? Getting vaccinated protects against severe illness from COVID-19, including the Delta variant. Monitoring COVID-19 incidence by vaccination status might provide early signals of potential changes in vaccine effectiveness that can be confirmed through robust controlled studies.
Journal Article
Depletion of Core Needle Biopsy Cellularity and DNA Content as a Result of Vigorous Touch Preparations
by
Rekhtman, Natasha
,
Silk, Tarik
,
Durack, Jeremy C.
in
Biopsy, Large-Core Needle
,
Humans
,
Kidney Neoplasms - pathology
2015
Touch preparations (TP) of core needle biopsies (CNBs) are used at some institutions for on-site assessment of CNB adequacy. In our clinical practice, we have encountered instances in which TPs resulted in substantial depletion of CNB cellularity.
To examine the effect of increasingly vigorous TPs on cellularity and DNA content of CNBs.
Ex vivo CNBs (n = 56) were performed on resected lung and kidney tumor specimens. For each specimen, CNBs were performed in quadruplicate on tumor and nontumor tissue and subjected to 1 of 4 TP methods: imprint, 1-cm drag, 2-cm drag, or full-slide drag. Overall cellularity in TPs relative to corresponding CNBs was estimated semiquantitatively. DNA was extracted and quantified from 12 TPs and corresponding CNBs. Two cytopathologists performed a blinded diagnostic assessment of Diff-Quik-stained TPs.
Cellularity of imprint, 1-cm, 2-cm, and full-slide TPs represented, on average, 19%, 33%, 41%, and 46% of total CNB cellularity, respectively (p = .003). Average DNA content in imprint, 1-cm, and 2-cm TPs was 0.3 μg (range, 0.1-0.8 μg), 0.4 μg (range, 0.1-1 μg), and 0.6 μg (range, 0.2-1.3 μg), respectively, which represented on average 15%, 36%, and 50%, respectively, of total CNB DNA content. Diagnostic accuracy was not inferior for less-extensive TPs, compared with more-extensive TPs.
Vigorous TPs may contain a substantial fraction of CNB cellularity and DNA content, whereas more-limited TPs are less disruptive to CNBs but remain suitable for cytologic assessment. We suggest avoiding excessively forceful TPs and, whenever clinically feasible, obtaining additional samples to ensure sufficient cellularity for potential ancillary studies.
Journal Article
Abscopal Effect with Liver-Directed Therapy: A Review of the Current Literature and Future Directions
2024
The liver is a common site for metastatic disease. In select patients with isolated liver metastases, surgical resection improves survival and may be potentially curative in patients with favorable “tumor biology”. However, when surgical resection is not feasible, liver-directed therapies (LDTs) can also improve outcomes, including survival, in the appropriate clinical situations. LDTs, including hepatic artery infusion, radioembolization, radiation, and ablation techniques, such as thermal ablation and histotripsy, offer local control and potential systemic effects, including the abscopal effect. The abscopal effect occurs when nontargeted, nontreated tumors regress following localized therapy to other tumors. Preclinical and clinical studies suggest that antigen-induced upregulation of key immune regulators plays a central role in this process. Unfortunately, clinical reports of the abscopal effect following LDT are exceedingly rare. However, histotripsy, a noninvasive, nonionizing, and nonthermal ablation technique, may induce an abscopal effect more frequently and robustly than other LDTs. Histotripsy enhances tumor immunogenicity through precise acoustic cavitation that better preserves the local tissue architecture while increasing antigen release, resulting in a robust local and systemic immune response. Ongoing trials are investigating these immunogenic mechanisms and the ability to generate an abscopal effect more reliably with adjuncts such as checkpoint inhibitors. This work has significant implications regarding the management of patients with liver metastasis.
Journal Article
Application of a life table approach to assess duration of BNT162b2 vaccine-derived immunity by age using COVID-19 case surveillance data during the Omicron variant period
by
Meyer, Stephanie
,
Pietrowski, Michael
,
Khan, Saadiah I.
in
Age groups
,
Biology and Life Sciences
,
COVID-19
2023
Background SARS-CoV-2 Omicron variants have the potential to impact vaccine effectiveness and duration of vaccine-derived immunity. We analyzed U.S. multi-jurisdictional COVID-19 vaccine breakthrough surveillance data to examine potential waning of protection against SARS-CoV-2 infection for the Pfizer-BioNTech (BNT162b) primary vaccination series by age. Methods Weekly numbers of SARS-CoV-2 infections during January 16, 2022–May 28, 2022 were analyzed by age group from 22 U.S. jurisdictions that routinely linked COVID-19 case surveillance and immunization data. A life table approach incorporating line-listed and aggregated COVID-19 case datasets with vaccine administration and U.S. Census data was used to estimate hazard rates of SARS-CoV-2 infections, hazard rate ratios (HRR) and percent reductions in hazard rate comparing unvaccinated people to people vaccinated with a Pfizer-BioNTech primary series only, by age group and time since vaccination. Results The percent reduction in hazard rates for persons 2 weeks after vaccination with a Pfizer-BioNTech primary series compared with unvaccinated persons was lowest among children aged 5–11 years at 35.5% (95% CI: 33.3%, 37.6%) compared to the older age groups, which ranged from 68.7%–89.6%. By 19 weeks after vaccination, all age groups showed decreases in the percent reduction in the hazard rates compared with unvaccinated people; with the largest declines observed among those aged 5–11 and 12–17 years and more modest declines observed among those 18 years and older. Conclusions The decline in vaccine protection against SARS-CoV-2 infection observed in this study is consistent with other studies and demonstrates that national case surveillance data were useful for assessing early signals in age-specific waning of vaccine protection during the initial period of SARS-CoV-2 Omicron variant predominance. The potential for waning immunity during the Omicron period emphasizes the importance of continued monitoring and consideration of optimal timing and provision of booster doses in the future.
Journal Article
Real-Time Split-Dose PET/CT-Guided Ablation Improves Colorectal Liver Metastasis Detection and Ablation Zone Margin Assessments without the Need for Repeated Contrast Injection
2022
Background: Real-time split-dose PET can identify the targeted colorectal liver metastasis (CLM) and eliminate the need for repeated contrast administration before and during thermal ablation (TA). This study aimed to assess the added value of pre-ablation real-time split-dose PET when combined with non-contract CT in the detection of CLM for ablation and the evaluation of the ablation zone and margins. Methods: A total of 190 CLMs/125 participants from two IRB-approved prospective clinical trials using PET/CT-guided TA were analyzed. Based on detection on pre-TA imaging, CLMs were categorized as detectable, non-detectable, and of poor conspicuity on CT alone, and detectable, non-detectable, and low FDG-avidity on PET/CT after the initial dose. Ablation margins around the targeted CLM were evaluated using a 3D volumetric approach. Results: We found that 129/190 (67.9%) CLMs were detectable on CT alone, and 61/190 CLMs (32.1%) were undetectable or of poor conspicuity, not allowing accurate depiction and targeting by CT alone. Thus, the theoretical 5- and 10-mm margins could not be defined in these tumors (32.1%) using CT alone. When TA intraprocedural PET/CT images are obtained and inspected (fused PET/CT), only 4 CLM (2.1%) remained undetectable or had a low FDG avidity. Conclusions: The addition of PET to non-contrast CT improved CLM detection for ablation targeting, margin assessments, and continuous depiction of the FDG avid CLMs during the ablation without the need for multiple intravenous contrast injections pre- and intra-procedurally.
Journal Article
COVID-19 Incidence and Mortality Among Unvaccinated and Vaccinated Persons Aged ≥12 Years by Receipt of Bivalent Booster Doses and Time Since Vaccination — 24 U.S. Jurisdictions, October 3, 2021–December 24, 2022
2023
On September 1, 2022, CDC recommended an updated (bivalent) COVID-19 vaccine booster to help restore waning protection conferred by previous vaccination and broaden protection against emerging variants for persons aged ≥12 years (subsequently extended to persons aged ≥6 months).* To assess the impact of original (monovalent) COVID-19 vaccines and bivalent boosters, case and mortality rate ratios (RRs) were estimated comparing unvaccinated and vaccinated persons aged ≥12 years by overall receipt of and by time since booster vaccination (monovalent or bivalent) during Delta variant and Omicron sublineage (BA.1, BA.2, early BA.4/BA.5, and late BA.4/BA.5) predominance.
During the late BA.4/BA.5 period, unvaccinated persons had higher COVID-19 mortality and infection rates than persons receiving bivalent doses (mortality RR = 14.1 and infection RR = 2.8) and to a lesser extent persons vaccinated with only monovalent doses (mortality RR = 5.4 and infection RR = 2.5). Among older adults, mortality rates among unvaccinated persons were significantly higher than among those who had received a bivalent booster (65-79 years; RR = 23.7 and ≥80 years; 10.3) or a monovalent booster (65-79 years; 8.3 and ≥80 years; 4.2). In a second analysis stratified by time since booster vaccination, there was a progressive decline from the Delta period (RR = 50.7) to the early BA.4/BA.5 period (7.4) in relative COVID-19 mortality rates among unvaccinated persons compared with persons receiving who had received a monovalent booster within 2 weeks-2 months. During the early BA.4/BA.5 period, declines in relative mortality rates were observed at 6-8 (RR = 4.6), 9-11 (4.5), and ≥12 (2.5) months after receiving a monovalent booster. In contrast, bivalent boosters received during the preceding 2 weeks-2 months improved protection against death (RR = 15.2) during the late BA.4/BA.5 period. In both analyses, when compared with unvaccinated persons, persons who had received bivalent boosters were provided additional protection against death over monovalent doses or monovalent boosters. Restored protection was highest in older adults. All persons should stay up to date with COVID-19 vaccination, including receipt of a bivalent booster by eligible persons, to reduce the risk for severe COVID-19.
Journal Article
Trends in Laboratory-Confirmed SARS-CoV-2 Reinfections and Associated Hospitalizations and Deaths Among Adults Aged ≥18 Years — 18 U.S. Jurisdictions, September 2021–December 2022
2023
Although reinfections with SARS-CoV-2 have occurred in the United States with increasing frequency, U.S. epidemiologic trends in reinfections and associated severe outcomes have not been characterized. Weekly counts of SARS-CoV-2 reinfections, total infections, and associated hospitalizations and deaths reported by 18 U.S. jurisdictions during September 5, 2021-December 31, 2022, were analyzed overall, by age group, and by five periods of SARS-CoV-2 variant predominance (Delta and Omicron [BA.1, BA.2, BA.4/BA.5, and BQ.1/BQ.1.1]). Among reported reinfections, weekly trends in the median intervals between infections and frequencies of predominant variants during previous infections were calculated. As a percentage of all infections, reinfections increased substantially from the Delta (2.7%) to the Omicron BQ.1/BQ.1.1 (28.8%) periods; during the same periods, increases in the percentages of reinfections among COVID-19-associated hospitalizations (from 1.9% [Delta] to 17.0% [Omicron BQ.1/BQ.1.1]) and deaths (from 1.2% [Delta] to 12.3% [Omicron BQ.1/BQ.1.1]) were also substantial. Percentages of all COVID-19 cases, hospitalizations, and deaths that were reinfections were consistently higher across variant periods among adults aged 18-49 years compared with those among adults aged ≥50 years. The median interval between infections ranged from 269 to 411 days by week, with a steep decline at the start of the BA.4/BA.5 period, when >50% of reinfections occurred among persons previously infected during the Alpha variant period or later. To prevent severe COVID-19 outcomes, including those following reinfection, CDC recommends staying up to date with COVID-19 vaccination and receiving timely antiviral treatments, when eligible.
Journal Article
Feasibility of a Modified Biopsy Needle for Irreversible Electroporation Ablation and Periprocedural Tissue Sampling
by
Monette, Sebastien
,
Wimmer, Thomas
,
Srimathveeravalli, Govindarajan
in
Ablation Techniques - instrumentation
,
Ablation Techniques - methods
,
Animals
2016
Objectives:
To test the feasibility of modified biopsy needles as probes for irreversible electroporation ablation and periprocedural biopsy.
Methods:
Core biopsy needles of 16-G/9-cm were customized to serve as experimental ablation probes. Computed tomography-guided percutaneous irreversible electroporation was performed in in vivo porcine kidneys with pairs of experimental (n = 10) or standard probes (n = 10) using a single parameter set (1667 V/cm, ninety 100 µs pulses). Two biopsy samples were taken immediately following ablation using the experimental probes (n = 20). Ablation outcomes were compared using computed tomography, simulation, and histology. Biopsy and necropsy histology were compared.
Results:
Simulation-suggested ablations with experimental probes were smaller than that with standard electrodes (455.23 vs 543.16 mm2), although both exhibited similar shape. Computed tomography (standard: 556 ± 61 mm2, experimental: 515 ± 67 mm2; P = .25) and histology (standard: 313 ± 77 mm2, experimental: 275 ± 75 mm2; P = .29) indicated ablations with experimental probes were not significantly different from the standard. Histopathology indicated similar morphological changes in both groups. Biopsies from the ablation zone yielded at least 1 core with sufficient tissue for analysis (11 of the 20).
Conclusions:
A combined probe for irreversible electroporation ablation and periprocedural tissue sampling from the ablation zone is feasible. Ablation outcomes are comparable to those of standard electrodes.
Journal Article