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PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
Within 24 h, cellular fractions were stored in Trizol (Invitrogen, Carlsbad, CA) at −80 °C (the Netherlands) or transferred to PAXgene blood RNA tubes (QIAGEN, Venlo, the Netherlands) and stored at −20 °C (Austria).
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
RNA isolation and RT-qPCR were performed in Amsterdam, the Netherlands, while AIPF analysis took place in Vienna, Austria.
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
Bone marrow histology and cytomorphology were centrally reviewed.
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
Cytomorphological (CM) examination of Wright-Giemsa-stained smears was performed independently at St. Anna Children’s Hospital (Vienna, 10% cutoff) and the Princes Maxima Centre (Utrecht, the Netherlands, 1% cutoff), following respective study protocols.
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
CM and histology were reported as either “positive”, “negative”, “inconclusive”, “dubious”, or “suspicious”.
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
In this study, inconclusive and dubious samples were classified as negative, while suspicious samples were considered positive.
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
mRNA extraction, complementary DNA (cDNA) synthesis and RT-qPCR followed established protocols .
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
mRNA was isolated from PAXgene blood RNA tubes (QIAGEN) using the PAXgene Blood RNA Kit (QIAGEN), or from cellular fractions stored in Trizol (Invitrogen), per manufacturer instructions.
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
RNA concentration and quality were measured using an ND-1000 spectrophotometer (Nanodrop).
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
cDNA synthesis was done using the High-Capacity RNA-to-cDNA™ Kit (Applied Biosystems, Foster City, CA, USA) .
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
RT-qPCR was performed on the Viia7 (Applied Biosystems, Carlsbad, CA, USA) and analyzed using QuantStudio software v1.6 (Applied Biosystems).
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
The housekeeping gene glucuronidase beta (GUSB) and the neuroblastoma-specific mRNA marker PHOX2B were used as single markers .
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
ADRN markers (TH, CHRNA3 and GAP43), and MES markers (POSTN, PRRX1 and flavin-containing monooxygenase 3 (FMO3)), were performed in multiplex panels .
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
mRNA expression was normalized to GUSB (ΔCt = Ctmarker – CtGUSB).
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
Samples with both GUSB Ct > 25 and PHOX2B negativity were excluded.
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
A sample was scored positive if at least one of the markers scored positive, according to previously published thresholds .
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
Level of mRNA detection (‘infiltration’) was calculated relative to neuroblastoma cell line IMR32 (2^ΔΔCT (ΔCTsample – ΔCTIMR32) * 100%).
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
Median relative expression of positive markers was used to calculate infiltration level.
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
Due to the calculations made relative to the expression in IMR32, calculated infiltrations can exceed 100%.
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
For bilateral samples, the highest infiltration level was used.
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
MES markers POSTN and PRRX1 were scored based on previously published thresholds relative to both GUSB and FMO3 expression .
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
High expression of POSTN or PRRX1 and low expression of FMO3 identify MES neuroblastoma cells in bone marrow samples.
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
Bone marrow aspirates were collected in EDTA tubes and subjected to density gradient centrifugation to isolate the mononuclear fraction, which also contains disseminated neuroblastoma cells.
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
Cytospins (0.8–1.5 × 10 mononuclear cells (MNCs) per slide) were prepared, fixated and immunocytologically stained with labeled antibodies for GD2 and CD56 (Anti-GD2-FITC, Anti-CD56-Biotin, Mouse-Anti-Biotin-Cy3) (Supplemental Table 1A).
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
Automated imaging (Axioplan 2, Zeiss, TRITC, FITC and DAPI filter) and analysis (Metafer 4, RCDetect classifier, Metasystems) identified DTCs .
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
The total bone marrow MNC count per slide was extrapolated from representative measurements and GD2/CD56-positive cells were counted as DTCs.
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
If fewer than four DTCs or ambiguous cells were detected, iFISH was performed using FISH probes (Metasystems) for primary tumor-specific aberrations (e.g., MYCN amplification, 1p deletion, 17q gain).
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
Each analysis included positive and negative controls.
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
If a sample was negative for both GD2 and CD56, no GD2- and/or CD56-positive tumor cells were detected.
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
Infiltration was reported as the fraction of DTCs within MNC count .
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
Detailed protocols are provided in Supplemental Data.
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
Archived bone marrow cytopins from patient 166 with metastatic neuroblastoma were analyzed using imaging mass cytometry for twelve tumor-specific markers (antibodies against GD2, CD56/NCAM, CHGA, S100B, CXCR4, ELAVL4, GATA3, PRPH, SOX10, Vimentin, CD44, CD24) (Supplemental Table 1B), markers for nucleus detection and Ki-67 as a proliferation marker, as described in Lazic et al. (personal communication).
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
Patient 166 was chosen due to the availability of multiple sequential timepoints in our study.
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
Samples were thawed for 15 min at RT, fixed in 4% PFA (Carl Roth) at 4 °C for 30 min, washed twice in TBS and then blocked with 2% BSA (Carl Roth) and 0.1% Tween-20 (Merck) in TBS at RT for 1 h. Meanwhile, antibody cocktails were retrieved from −80 °C and thawed for 15 min at 4 °C before staining overnight at 4 °C.
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
The following day, slides were washed twice (5 min per wash) in TBS, stained with the DNA intercalator Iridium (Fluidigm) and then dried with compressed air before IMC measurement with the Hyperion imaging system (Fluidigm) and CyTOF Software v7.
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
Acquired images were background-corrected using spillover compensation with R CATALYST v.1.20.1 package , hot pixel removal through IMC-Denoise and semi-automated background correction .
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
Nuclei were segmented using a Cellpose model fine-tuned in a human-in-the-loop approach with Cellpose 2.0 .
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
Single-cell mean marker expressions were subsequently exported based on inferred segmentation masks.
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
Statistical analysis was performed using SPSS v29 (RRID:SCR_002865; IBM Corporation, Armonk, NY, USA).
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
Continuous variables were reported as median (10-90th percentiles), mean ± standard deviation, or mean (quartiles).
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
Spearman correlations (95% confidence interval (CI)) assessed AIPF and RT-qPCR infiltration levels in paired samples.
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
Independent samples t-test or Mann–Whitney U tests (for non-normal distributions) compared continuous variables.
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
Graphs were generated using GraphPad Prism v9.3.1 (RRID:SCR_002798; GraphPad Software, Boston, Massachusetts, USA).
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
One hundred eight (108) children with high-risk neuroblastoma, with a median age of 36 months at diagnosis (range 3–274 months) were included in this study (Table 1).
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
Five hundred nine (509) bone marrow samples were collected (Fig. 1A & B), shipped and analyzed in specialized laboratories for AIPF and RT-qPCR.
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
The current standard-of-care diagnostic tests, i.e. CM or histology, were performed locally.
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
To investigate the feasibility of performing multi-modal bone marrow disease analysis on the same sample, we first evaluated how often each technique was successfully performed in our cohort (Table 2).
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
Due to low cellularity in 96 samples (19%), no cytospins could be made and thus AIPF was performed on 413 samples.
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
Twelve (3%) were not evaluable by AIPF due to high autofluorescence or low cell counts.
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
Sequential iFISH analysis visualizing tumor-typical cytogenetic aberrations was performed in forty ambiguously positive samples.
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
In 25/40 (63%), iFISH confirmed the same number of positive cells as with automated immunofluorescence alone.
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
In 15/40 (38%), the number of positive cells detected by AIPF differed from that detected by automated immunofluorescence.
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
However, only in 7/15 (47%), iFISH-result classified samples as negative or led to inconclusive results.
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
Interestingly, 5 of these 7 (71%) were RT-qPCR positive.
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
Of the 509 samples collected, neuroblastoma mRNA detection failed in nine (2%) because of low cDNA concentration.
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
However, in eight of these cases, the paired bone marrow sample collected from the contralateral side yielded sufficient cDNA and could be included in the analyses (yielding 508).
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
Standard-of-care diagnostics (CM or histology) was performed in 505 samples of which 1/505 (0.2%) was not evaluable by either, CM or histology (118 CM only, 2 histology only, 384 CM and histology) (Fig. 1B and Table 2).
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
Fig. 1Study design, cohort and benchmarking against standard of care bone marrow assessment.
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
A Outline of study cohort and analytical workflows for automated immunofluorescence plus fluorescence in situ hybridization (AIPF), RT-qPCR and cytomorphology/histology.
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
B Consort diagram depicting sample inclusion and exclusion.
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
C Contribution of AIPF, RT-qPCR (adrenergic (ADRN)-mRNA markers) and cytomorphology (CM)/histology.
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
Venn diagram shows samples positive for at least one technology.
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
Each circle represents positive results of one technique.
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
N = 395 samples analyzed by all three techniques.
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
N = 236 samples positive by ≥ 1 technique.
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
D Representative microscopy image for GD2, CD56/NCAM and DAPI for a bone marrow specimen that was identified as positive only by AIPF, and negative by RT-qPCR and CM/histology.
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
Scale bar represents 20 µm.
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
E Level of tumor cell infiltration according to AIPF (y-axis; give n as % DTCs detected by AIPF) in specimens with single or combined positivity for AIPF, RT-qPCR and CM/histology (x-axis; + positive,—negative).
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
Box plots represent 10–90 percentiles, line shows median. **
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
= 0.0023; *** = 0.0003.
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
F Level of tumor cell infiltration according to RT-qPCR-ADRN (y-axis; given as % relative to neuroblastoma cell line IMR32) in specimen with single or combined positivity for AIPF, RT-qPCR-ADRN and CM/histology (x-axis; + positive,—negative).
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
Box plots represent 10–90 percentiles, line shows median. *
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
= 0.0135; ** = 0.0007; *** < 0.0001 Study design, cohort and benchmarking against standard of care bone marrow assessment.
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
A Outline of study cohort and analytical workflows for automated immunofluorescence plus fluorescence in situ hybridization (AIPF), RT-qPCR and cytomorphology/histology.
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
B Consort diagram depicting sample inclusion and exclusion.
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
C Contribution of AIPF, RT-qPCR (adrenergic (ADRN)-mRNA markers) and cytomorphology (CM)/histology.
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
Venn diagram shows samples positive for at least one technology.
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
Each circle represents positive results of one technique.
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
N = 395 samples analyzed by all three techniques.
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
N = 236 samples positive by ≥ 1 technique.
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
D Representative microscopy image for GD2, CD56/NCAM and DAPI for a bone marrow specimen that was identified as positive only by AIPF, and negative by RT-qPCR and CM/histology.
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
Scale bar represents 20 µm.
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
E Level of tumor cell infiltration according to AIPF (y-axis; give n as % DTCs detected by AIPF) in specimens with single or combined positivity for AIPF, RT-qPCR and CM/histology (x-axis; + positive,—negative).
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
Box plots represent 10–90 percentiles, line shows median. **
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
= 0.0023; *** = 0.0003.
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
F Level of tumor cell infiltration according to RT-qPCR-ADRN (y-axis; given as % relative to neuroblastoma cell line IMR32) in specimen with single or combined positivity for AIPF, RT-qPCR-ADRN and CM/histology (x-axis; + positive,—negative).
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
Box plots represent 10–90 percentiles, line shows median. *
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
= 0.0135; ** = 0.0007; *** < 0.0001 Table 1Patient characteristicsNumber of patients108Country Austria39 Netherlands69Stage (INSS) 32 4105 Unknown1Age at diagnosis (months) < 1825 ≥ 1883 Median36 Range3–274Sex Male65 Female43MYCN amplification status Amplified38 Non-amplified69 Unknown1INSS International Neuroblastoma Staging System Patient characteristics INSS International Neuroblastoma Staging System Table 2Technique performance on bone marrow liquid biopsy samples from patients with high-risk neuroblastomaSamples analyzed[number]Analysis successful[number]Analysis failed [number (%)]Samples not analyzed [number (%)]AIPF*41340112 (3%)96 (19%)Cell numbersiFISHperformed<1 million3229 131-2 million104104130≥2 million264264250Unknown134 19RT-qPCR*5095081 (0.2%)GUS Ct >25Not applicableOne side only: 8Both sides: 1CM*503435Suspicious: 268 (13.5%)Not representative: 36Inconclusive: 63Dubious: 2Histology*387333Suspicious: 1254 (14%)Not representative: 5122Inconclusive: 49 Total number of samples collected n 509 Technique performance on bone marrow liquid biopsy samples from patients with high-risk neuroblastoma iFISH performed Total number of samples collected n 509 Of the 413 samples exchanged, 184 (45%) were from Austrian and 229 (55%) from Dutch patients (Supplemental Fig. 1A).
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
For > 95% of these, it was possible to perform AIPF and RT-qPCR, as well as cytomorphological examination of bone marrow smears and/or histological examination of bone trephines (Supplemental Fig. 1B).
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
In total 395 samples were analyzed by AIPF, RT-qPCR and CM/histology (Fig. 1B).
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
Sample preparation time (i.e. time from sampling to cytospin preparation), was shorter for Austrian bone marrow aspirates (Supplemental Fig. 1C).
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
Mean cell counts were 3.80 million (range 130,000–7.97 million) for Austrian and 1.95 million (237,000–5.00 million) for Dutch samples (Supplemental Fig. 1D).
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
The median turnaround time (sample collection to clinical report) for AIPF was 6 days (range 1 to 29 days), for the Austrian samples, where the results are used clinically.
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
Two hundred thirty-six (236) bone marrows (60%) were positive for one or more techniques (Fig. 1B).
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
We conclude that performing all three analyses on the same bone marrow specimen is feasible in an international multi-center setting.
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
In the cohort of 395 multi-modal bone marrow analyses, we next determined the contribution of each technique to MRD detection and the link of DTC infiltration to uni- versus multi-modal assessment.
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
In the 395 samples analyzed by all three techniques—AIPF, RT-qPCR-ADRN and CM/histology—64 (16%) were positive by all techniques and 159 (40%) negative.
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
Among the 236 bone marrow specimens (60%) that showed positivity for at least one of the techniques, RT-qPCR-ADRN detected bone marrow disease more frequently than AIPF or CM/histology (216 RT-qPCR-ADRN vs. 108 AIPF vs. 112 CM/histology).
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
Additionally, RT-qPCR-ADRN showed exclusive positivity in eighty, AIPF in four and CM/histology in sixteen cases (Fig. 1C & D & Supplemental Table 2).
PMC12317575
Sensitive detection of minimal residual disease and immunotherapy targets by multi-modal bone marrow analysis in high-risk neuroblastoma – a multi-center study
Interestingly, in CM/histology samples (n = 283), MRD-detection by AIPF was positive in 16% (n = 44) and RT-qPCR-ADRN was positive in 42% (n = 120); two of these cases were taken at diagnosis: both were RT-qPCR and one AIPF.