Circulating tumor plasma cells and peripheral blood measurable residual disease assessment in multiple myeloma patients not planned for upfront transplant

Circulating tumor plasma cells (CTPCs) provide a noninvasive alternative for measuring tumor burden in newly diagnosed multiple myeloma (NDMM). Moreover, measurable residual disease (MRD) assessment in peripheral blood (PBMRD) can provide an ideal alternative to bone marrow MRD, which is limited by its painful nature and technical challenges. However, the clinical significance of PBMRD in NDMM still remains uncertain. Additionally, data on CTPC in NDMM patients not treated with transplant are scarce. We prospectively studied CTPC and PBMRD in 141 NDMM patients using highly sensitive multicolor flow cytometry (HS-MFC). PBMRD was monitored at the end of three cycles (PBMRD1) and six cycles (PBMRD2) of chemotherapy in patients with detectable baseline CTPC. Patients received bortezomib-based triplet therapy and were not planned for an upfront transplant. Among baseline risk factors, CTPC ≥ 0.01% was independently associated with poor progression-free survival (PFS) (hazard ratio [HR] = 2.77; p = 0.0047) and overall survival (OS) (HR = 2.9; p = 0.023) on multivariate analysis. In patients with detectable baseline CTPC, undetectable PBMRD at both subsequent time points was associated with longer PFS (HR = 0.46; p = 0.0037), whereas detectable PBMRD at any time point was associated with short OS (HR = 3.25; p = 0.004). Undetectable combined PBMRD (PBMRD1 and PBMRD2) outperformed the serum-immunofixation-based response. On multivariate analysis, detectable PBMRD at any time point was independently associated with poor PFS (HR = 2.0; p = 0.025) and OS (HR = 3.97; p = 0.013). Thus, our findings showed that CTPC and PBMRD assessment using HS-MFC provides a robust, noninvasive biomarker for NDMM patients not planned for an upfront transplant. Sequential PBMRD monitoring has great potential to improve the impact of the existing risk stratification and response assessment models.

15-color highly sensitive flow cytometry assay for post anti-CD19 targeted therapy (anti-CD19-CAR-T and blinatumomab) measurable residual disease assessment in B-lymphoblastic leukemia/lymphoma: Real-world applicability and challenges

OBJECTIVES

Measurable residual disease (MRD) is the most relevant predictor of disease-free survival in B-cell acute lymphoblastic leukemia (B-ALL). We aimed to establish a highly sensitive flow cytometry (MFC)-based B-ALL-MRD (BMRD) assay for patients receiving anti-CD19 immunotherapy with an alternate gating approach and to document the prevalence and immunophenotype of recurrently occurring low-level mimics and confounding populations.

METHODS

We standardized a 15-color highly-sensitive BMRD assay with an alternate CD19-free gating approach. The study included 137 MRD samples from 43 relapsed/refractory B-ALL patients considered for anti-CD19 immunotherapy.

RESULTS

The 15-color BMRD assay with CD22/CD24/CD81/CD33-based gating approach was routinely applicable in 137 BM samples and could achieve a sensitivity of 0.0005%. MRD was detected in 29.9% (41/137) samples with 31.7% (13/41) of them showing <.01% MRD. Recurrently occurring low-level cells that showed immunophenotypic overlap with leukemic B-blasts included: (a) CD19+CD10+CD34+CD22+CD24+CD81+CD123+CD304+ plasmacytoid dendritic cells, (b) CD73bright/CD304bright/CD81bright mesenchymal stromal/stem cells (CD10+) and endothelial cells (CD34+CD24+), (c) CD22dim/CD34+/CD38dim/CD81dim/CD19-/CD10-/CD24- early lymphoid progenitor/precursor type-1 cells (ELP-1) and (d) CD22+/CD34+/CD10heterogeneous/CD38moderate/CD81moderate/CD19-/CD24- stage-0 B-cell precursors or ELP-2 cells.

CONCLUSIONS

We standardized a highly sensitive 15-color BMRD assay with a non-CD19-based gating strategy for patients receiving anti-CD19 immunotherapy. We also described the immunophenotypes of recurrently occurring low-level populations that can be misinterpreted as MRD in real-world practice.

Long-Term Cryopreservation of Peripheral Blood Stem Cell Harvest Using Low Concentration (4.35%) Dimethyl Sulfoxide with Methyl Cellulose and Uncontrolled Rate Freezing at -80 °C: An Effective Option in Resource-Limited Settings

Long-term cryopreservation of peripheral blood stem cells (PBSCs) is highly useful in the setting of tandem/multiple transplantations or treatment of relapse in the autologous hematopoietic stem cell transplantation (HSCT) setting. Even in allogeneic HSCT, donor lymphocyte infusions may be stored for months to years if excess stem cells are collected from donors. Cryopreservation is a delicate, complex, and costly procedure, and higher concentrations of dimethyl sulfoxide (DMSO), a commonly used cryoprotectant, can be toxic to cells and cause adverse effects in the recipient during infusions. In this study, we examined the effect of long-term cryopreservation using 4.35% DMSO (as final concentration) with methyl cellulose and uncontrolled rate freezing in a mechanical freezer (-80 °C) on the viability and colony-forming ability of CD34+ human PBSCs. For patients undergoing autologous HSCT, PBSCs were cryopreserved using DMSO (final concentration of 4.35%) with methyl cellulose. The post-thaw viability of PBSCs was determined using Trypan blue exclusion and flow cytometry-based 7-amino-actinomycin-D (FC-7AAD) methods. Concentrations of CD34+ stem cells and immune cell subsets in post-thaw PBSC harvest samples were assessed using multicolor flow cytometry, and the clonogenic potential of post-thaw stem cells was studied using a colony-forming unit (CFU) assay. CD34+ stem cell levels were correlated with the prestorage CD34 levels using the Pearson correlation test. The viability results in the Trypan blue dye exclusion method and the flow cytometry-based method were compared using Bland-Altman plots. We studied 26 PBSC harvest samples with a median cryopreservation duration of 6.6 years (range, 3.8 to 11.5 years). The median viability of post-thaw PBSCs was >80% using both methods, with a weak agreement between them (r = .03; P = .5). The median CD34+ stem cell count in the post-thaw samples was 9.13 × 106/kg (range, .44 to 26.27 × 106/kg). The CFU assay yielded a good proliferation and differentiation potential in post-thaw PBSCs, with a weak correlation between granulocyte macrophage CFU and CD34+ stem cell levels (r = .4; P = .05). Two samples that had been cryopreserved for >8 years showed low viability. Cryopreservation of PBSCs using 4.35% DMSO with methyl cellulose and uncontrolled freezing in a mechanical freezer at -80 °C allows the maintenance of long-term viability of PBSC for up to 8 years.

Activatable Nanoreporters for Real-Time Tracking of Macrophage Phenotypic States Associated with Disease Progression

Diagnosis of inflammatory diseases is characterized by identifying symptoms, biomarkers, and imaging. However, conventional techniques lack the sensitivities and specificities to detect disease early. Here, it is demonstrated that the detection of macrophage phenotypes, from inflammatory M1 to alternatively activated M2 macrophages, corresponding to the disease state can be used to predict the prognosis of various diseases. Activatable nanoreporters that can longitudinally detect the presence of the enzyme Arginase 1, a hallmark of M2 macrophages, and nitric oxide, a hallmark of M1 macrophages are engineered, in real-time. Specifically, an M2 nanoreporter enables the early imaging of the progression of breast cancer as predicted by selectively detecting M2 macrophages in tumors. The M1 nanoreporter enables real-time imaging of the subcutaneous inflammatory response that rises from a local lipopolysccharide (LPS) administration. Finally, the M1-M2 dual nanoreporter is evaluated in a muscle injury model, where an initial inflammatory response is monitored by imaging M1 macrophages at the site of inflammation, followed by a resolution phase monitored by the imaging of infiltrated M2 macrophages involved in matrix regeneration and wound healing. It is anticipated that this set of macrophage nanoreporters may be utilized for early diagnosis and longitudinal monitoring of inflammatory responses in various disease models.

Abstract 2879: Cell-autonomous Cxcl1 sustains tolerogenic circuitries and stromal inflammation via neutrophil-derived TNF in pancreatic cancer

Objective: We have shown that KRAS-TP53 genomic co-alteration is associated with immune-excluded microenvironments, chemoresistance, and poor survival in pancreatic ductal adenocarcinoma (PDAC) patients. By treating KRAS-TP53 cooperativity as a model for high-risk biology, we sought to define how cancer cell-autonomous transcriptional programs orchestrate tolerogenic circuitries and stromal inflammation to mediate chemoresistance.

Methods: Spatial neighborhood analysis via Imaging Mass Cytometry (IMC) was performed in human PDAC sections. Immune profiling and RNA-seq in whole tumors, bulk-RNA-seq in intratumoral neutrophilic(PMN)-MDSCs in orthotopic KPC tumors with/without CRISPR/Cas9 editing of Cxcl1 was performed. Effect of TNFR2 inhibition via etanercept on ex vivo co-cultures of intratumoral PMN-MDSC with KPC tumor cells/CAFs and T-cells, as well as in orthotopic KPC models in vivo with/without gemcitabine+paclitaxel was examined.

Results: Interrogation of cancer cell transcriptomes and IMC architecture in human tumors reveals enrichment of Cxcl1 in KRAS-TP53 co-altered PDAC. IMC-enabled spatial neighborhood analysis in KRAS-TP53 co-altered human tumors demonstrate spatial contiguity between PanCK+CXCL1+ tumor islands and cognate CD15+CXCR2+ PMN-MDSCs, with exclusion of CD8+ T-cells from tumor cell:MDSC communities. In murine orthotopic models, silencing of cancer cell-intrinsic Cxcl1 reprograms trafficking and functional dynamics of CXCR2+ PMN-MDSCs to overcomes T-cell exclusion, and controls tumor growth in a CD8+ T-cell dependent manner. Transcriptomes from KPC-Cxcl1KO tumors reveal enrichment in pathways encoding for T-cell effector activity, and attenuation in pathways related to innate immunoregulatory function. Mechanistically, neutrophil-derived TNF emerges as a central regulator of this immunologic rewiring, with transcriptomes from intratumoral KPC-Cxcl1KO PMN-MDSCs revealing a novel MAPK-reliant Cxcr2-Ikk-Map3k8-Tnf axis. Neutrophil-derived TNF instigates feed-forward Cxcl1 overproduction from tumor cells and CAFs, T-cell dysfunction, and inflammatory CAF polarization via transmembraneTNF-TNFR2 interactions. Systemic TNFR2 inhibition via etanercept augments T-cell activation, and mitigates tumor-wide Cxcl1 production, stromal inflammation, and CAF:tumor cell IL6-STAT3 signaling to improve sensitivity to chemotherapy in vivo.

Conclusion: By decoding the link between high-risk cancer cell genotypes, cell-autonomous inflammatory programs, and myeloid-enriched and T-cell-excluded contexts, we identify a previously unrecognized role of neutrophil-derived TNF in sustaining tolerogenic circuitries and stromal inflammation in the PDAC TME. Our data suggest that targeting context-dependent TNF signaling may overcome hallmarks of therapeutic resistance in PDAC.

Citation Format: Anna Bianchi, Iago De Castro Silva, Nilesh Deshpande, Samara Singh, Siddharth Mehra, Vanessa Garrido, Ifeanyichukwu Ogobuiro, Haleh Amirian, Christine Rafie, Zhiqun Zhou, Nagaraj Nagathihalli, Alejandro Villarino, Nipun Merchant, Jashodeep Datta. Cell-autonomous Cxcl1 sustains tolerogenic circuitries and stromal inflammation via neutrophil-derived TNF in pancreatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2879.

Abstract C031: Targeting granulocytic MDSC-derived inflammasome activation to overcome stromal inflammation in pancreatic cancer

Objective: The major drivers of therapeutic resistance in pancreatic ductal adenocarcinoma (PDAC) are myeloid cell-derived signaling that sustains immune tolerance/exclusion, and interleukin-1 (IL-1)-mediated inflammatory polarization of cancer-associated fibroblasts (iCAF) which promotes stromal inflammation by elaborating soluble factors (i.e., CXCL1, IL-6) that further accelerate myeloid chemotaxis. Moreover, we have recently shown that enrichment of pathways related to inflammasome activation-which involves recruitment of ASC complexes culminating in IL-1β generation—is a major contributor to chemoresistance in advanced PDAC patients. However, how these disparate pathways converge to mediate stromal inflammation in PDAC is incompletely understood. Methods: Single-cell RNA sequencing (scRNAseq) and caspase-1 luminescence assays in human and genetically engineered mouse (GEM) PDAC models were interrogated to identify cellular source of inflammasome-derived IL-1β. Gene set enrichment analysis in bulk RNA-sequencing data and signal transduction studies examined novel pathways associated with inflammasome activation in granulocytic myeloid-derived suppressor cells (gMDSC). scRNAseq and ASC-speck formation via confocal microscopy in intratumoral gMDSCs was performed in PKT mice treated with a novel anti-ASC antibody. Results: scRNAseq in human and GEM PDAC models revealed gMDSCs as the dominant source of inflammasome activation-derived IL1B expression. Functionally, caspase-1 activation and ASC-speck formation was strongest in intratumoral gMDSCs, compared with tumor-cell, CAF, macrophage, T-cell, and dendritic cell, compartments. Investigating developmental trajectories of single-cell transcriptomes in intratumoral gMDSCs from Panc02 tumors revealed an activated Cd14+ gMDSC state with strong co-expression of Cxcr2 and Il1b. As such, treatment of PKT GEM and orthotopically injected KPC tumor-bearing mice with CXCR2 inhibitor AZD5069 significantly abrogated inflammasome activation in intratumoral and splenic gMDSCs. In vitro signal transduction and RNA-seq studies revealed cooperativity between Tlr4-Myd88 and Cxcr2-Tpl2-p38 signaling in activating gMDSC-restricted inflammasome signaling. Co-culture of intratumoral gMDSCs and KPC CAFs ex vivo revealed strong induction of CAF-intrinsic Il6/Cxcl1 expression, which was dependent in part on CAF-Il1r1 expression and inflammasome activation in gMDSCs. We next used antibody to target ASC-a common downstream adaptor complex inducing inflammasomes-in vivo. Treatment of PKT mice with this anti-ASC antibody significantly attenuated ASC-speck formation in intratumoral gMDSCs as well as CAF-specific Il6/Cxcl1 expression via scRNAseq. Conclusions: These data uncover granulocytic MDSCs as the dominant source of inflammasome activation derived-IL1β in the PDAC TME, which promotes stromal inflammation via iCAF polarization. Therapeutic approaches-such as anti-ASC treatment-targeting gMDSC-intrinsic inflammasome activation may mitigate stromal inflammation and overcome therapeutic resistance in PDAC.

Citation Format: Nilesh Deshpande, Anna Bianchi, Iago De Castro Silva, Vanessa Garrido, Siddharth Mehra, Samara Singh, Ifeanyichukwu Ogobuiro, Nagaraj Nagathihalli, Nipun B. Merchant, Jashodeep Datta. Targeting granulocytic MDSC-derived inflammasome activation to overcome stromal inflammation in pancreatic cancer [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer; 2022 Sep 13-16; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2022;82(22 Suppl):Abstract nr C031.

Abstract C020: Neutrophil-mediated stromal-tumor IL-6/STAT-3 signaling underlies the association between neutrophil-to-lymphocyte ratio dynamics and chemotherapy response in localized pancreatic cancer: A hybrid clinical-preclinical study

Background: Partial/complete pathologic response following neoadjuvant chemotherapy (NAC) in pancreatic cancer (PDAC) patients undergoing pancreatectomy is associated with improved survival. We sought to determine whether neutrophil-to-lymphocyte ratio (NLR) dynamics predict pathologic response following chemotherapy in PDAC, and if manipulating NLR impacts chemosensitivity in preclinical models and uncovers potential mechanistic underpinnings underlying these effects. Methods: Pathologic response in PDAC patients (n=94) undergoing NAC and pancreatectomy (7/2015-12/2019) was dichotomized as partial/complete or poor/absent (case-cohort design). Bootstrap-validated multivariable models assessed associations between pre-chemotherapy NLR (%neutrophils÷%lymphocytes) or NLR dynamics during chemotherapy (ΔNLR=pre-surgery—pre-chemotherapy NLR) and pathologic response, disease-free survival (DFS), and overall survival (OS). To preclinically model effects of NLR attenuation on chemosensitivity, C57BL/6 mice (n=8-10/arm) were orthotopically injected with KrasG12D/+;Trp53fl/+;PdxCre(KPC) cells and randomized to vehicle, NLR-attenuating anti-Ly6G, gemcitabine/paclitaxel, or gemcitabine/paclitaxel+anti-Ly6G treatments. Results: In 94 PDAC patients undergoing NAC (median:4 months), pre-chemotherapy NLR (P&lt;0.001) and ΔNLR attenuation during NAC (P=0.002) were independently associated with partial/complete pathologic response. An NLR score=pre-chemotherapy NLR+ΔNLR correlated with DFS (P=0.006) and OS (P=0.002). Upon preclinical modeling, combining NLR-attenuating anti-Ly6G treatment with gemcitabine/paclitaxel—compared with gemcitabine/paclitaxel or anti-Ly6G alone—not only significantly reduced tumor burden and metastatic outgrowth, but also augmented tumor-infiltrating CD107a+-degranulating CD8+ T-cells (P&lt;0.01) while dampening inflammatory cancer-associated fibroblast (CAF) polarization (P=0.006) and chemoresistant IL-6/STAT-3 signaling in vivo. Neutrophil-derived IL-1β emerged as a novel mediator of stromal inflammation, inducing inflammatory CAF polarization and CAF-tumor cell IL-6/STAT-3 signaling in ex vivo co-cultures. Conclusions: Therapeutic strategies to mitigate neutrophil-CAF-tumor cell IL-1β/IL-6/STAT-3 signaling during NAC may improve pathologic responses and/or survival in PDAC.

Citation Format: Iago De Castro Silva, Anna Bianchi, Nilesh Deshpande, Prateek Sharma, Siddharth Mehra, Peter Hosein, Deukwoo Kwon, Nipun Merchant, Jashodeep Datta. Neutrophil-mediated stromal-tumor IL-6/STAT-3 signaling underlies the association between neutrophil-to-lymphocyte ratio dynamics and chemotherapy response in localized pancreatic cancer: A hybrid clinical-preclinical study [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer; 2022 Sep 13-16; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2022;82(22 Suppl):Abstract nr C020.

Expression levels and patterns of B-cell maturation antigen in newly diagnosed and relapsed multiple myeloma patients from Indian subcontinent

BACKGROUND

Many novel therapies are being evaluated for the treatment of Multiple myeloma (MM). The cell-surface protein B-cell maturation antigen (BCMA, CD269) has recently emerged as a promising target for CAR-T cell and monoclonal-antibody therapies in MM. However, the knowledge of the BCMA expression-pattern in myeloma patients from the Indian subcontinent is still not available. We present an in-depth study of BCMA expression-pattern on abnormal plasma cells (aPC) in Indian MM patients.

METHODS

We studied BM samples from 217 MM patients (211-new and 6-relapsed) with a median age of 56 years (range, 30-78 years & M:F-2.29) and 20 control samples. Expression levels/patterns of CD269 (clone-19f2) were evaluated in aPCs from MM patients and in normal PCs (nPC) from uninvolved staging bone marrow samples (controls) using multicolor flow cytometry (MFC). Expression-level of CD269 was determined as a ratio of mean fluorescent intensity (MFI-R) of CD269 in PCs to that of non-B-lymphocytes and expression-pattern (homogenous/heterogeneous) as coefficient-of-variation of immunofluorescence (CVIF).

RESULTS

Median (range) percentage of CD269-positive abnormal-PCs in total PCs was 71.6% (0.49-99.29%). The MFI-R (median, range) of CD269 was significantly higher in aPCs (4.13, 1.12-26.88) than nPCs (3.33, 1.23-12.87), p < .0001. Median (range) MFI of CD269 at diagnosis and relapse were 2.39 (0.77-9.57) and 2.66 (2.15-3.23) respectively. CD269 levels were similar at diagnosis and relapse, p = .5529.

CONCLUSIONS

We demonstrated that BCMA/CD269 is highly expressed in aPCs from a majority of MM patients, both at diagnosis and relapse. Thus, BCMA is a valuable target for therapy for Indian MM patients.

Abstract 1328: Deciphering the role of CREB1 in shaping the tumor immune landscape of pancreatic ductal adenocarcinoma

Background: Pancreatic ductal adenocarcinoma (PDAC) remains a major therapeutic challenge with hallmarks including oncogenic mutations, desmoplastic architecture, and an immunosuppressive tumor microenvironment (TME). Previously, we have identified Cyclic AMP Response Element Binding protein 1 (CREB) as an oncogenic transcriptional factor downstream of KRAS that promotes disease aggressiveness, poor survival, and immune exclusion. Based on these, we sought to determine the impact of tumor intrinsic CREB deletion in shaping the tumor immune microenvironment.

Methods: We have generated a novel genetically engineered mouse model (GEMM) of pancreas-specific CREB deletion (CREBfl/fl) in LSL-KrasG12D/+; Trp53 R172H/+; Pdx1Cre/+ (KPC) mice that phenocopy human PDAC disease. CRISPR/CAS9-based genomic editing was utilized to ablate CREB (CREBKO) in KPC tumor cells. RNA-sequencing analysis was performed in KPC CREB wild type (CREBEV) vs. CREBKO tumor cells to identify CREB-mediated transcriptomic changes. Syngeneic orthotopic tumor implantation of these cells was performed into the pancreata of mice. High dimensional immunophenotyping was accomplished to assess changes in the immune subsets with CREB deletion in murine tumors. Additionally, these tissues were processed for immunohistochemical and qPCR-based analysis to assess changes in fibroinflammatory and immune mediators.

Results: Pancreas-specific CREB deletion in the KPC GEMM led to a significant reduction in the primary tumor burden, liver metastases and improved overall survival compared to wild-type KPC. Additionally, CREB deletion significantly remodeled the tumor stroma, as evidenced by the reduction in the expression of fibroinflammatory and immunosuppressive markers. In assessing the immune repercussions of CREB deletion in pancreatic tumors, we observed a decreased infiltration of CD11b+ myeloid-derived suppressor cells (MDSCs) and granulocytic-PMN MDSCs (CD11b+ Ly6Ghigh Ly6Clow F4/80-), with a concomitant increase in the antigen-presenting M1-like macrophages (F4/80+ MHC-II high CD86 high). Also, CREB ablation in these tumors further facilitated increased infiltration of activated effector CD8+ T cells resulted in enhanced anti-tumor immune response within the PDAC TME. Mechanistically, RNA transcriptomic and secretome analysis in CREBKO Vs. the wild type KPC tumor cells identified several differentially expressed immunomodulatory soluble mediators responsible for shaping CREB dependent immunogenic landscape in PDAC.

Conclusion: Overall, depleting CREB reshapes the tumor immune landscape to reduce innate immunosuppressive myeloid infiltration and reinvigorate the antitumor T cell immune responses to improve overall survival in PDAC.

Citation Format: Siddharth Mehra, Vanessa Garrido, Samara Singh, Iago D Silva, Luis Alberto Nivelo, Anna Bianchi, Shrey Modi, Zhiqun Zhou, Austin Dosch, Nilesh Deshpande, Supriya Srinivasan, Christine Rafie, Ifeanyichukwu Ogobuiro, Xi Chen, Alejandro Villarino, Jashodeep Datta, Nipun Merchant, Nagaraj Nagathihalli. Deciphering the role of CREB1 in shaping the tumor immune landscape of pancreatic ductal adenocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1328.

Abstract 1565: Targeting stromal-specific p38 MAPK signaling to stifle inflammatory reprogramming of cancer-associated fibroblasts in pancreatic cancer

Introduction: Major contributors to therapeutic resistance in pancreatic ductal adenocarcinoma (PDAC) are the desmoplastic stroma that acts as a barrier to drug delivery and effector immune cell infiltration. In our efforts to identify mediators of therapeutic resistance, we identified the pro-inflammatory cytokine interleukin-1α (IL-1) to be critical in the activation and reprogramming of neighboring cancer-associated fibroblasts (CAFs) within the stroma to a pro-inflammatory phenotype to promote myeloid cell chemotaxis. Our mechanistic studies have identified the p38 MAPK pathway as a novel mediator of IL-1-induced CAF activation from quiescent stellate cells into the inflammatory fibroblast. Our central hypothesis is that disruption of the IL-1/p38 MAPK signaling cascade in pancreatic stellate cells (PSCs) and CAFs can improve therapeutic resistance by remodeling the fibrotic stromal landscape and the overall immune microenvironment in PDAC tumors.

Methods: Inhibition of phosphorylated p38 MAPK was achieved pharmacologically with Pexmetinib and genetically with an shRNA lentiviral system in CAF and PSC cell lines. Inflammatory PSC/CAF activation was determined by qPCR, immunofluorescence, and vitamin A assay. Ptf1acre/+;LSL-KrasG12D/+; Tgfbr2flox/flox (PKT) mice were treated with the p38 inhibitor, pexmetinib (30mg/kg, daily PO), or vehicle control for 2.5 weeks prior to sacrifice. For survival studies, PKT mice were treated with vehicle, gemcitabine (20 μg/twice weekly), pexmetinib, or combination until moribund.

Results: Inhibition of p38 MAPK in PSCs prevented activation into an inflammatory fibroblast in vitro when stimulated with IL-1 or tumor cell cocultures. p38 MAPK inhibition in vivo resulted in signification reduction of PDGFR+ CAFs in a PDAC GEMM. Additionally, p38 MAPK inhibition resulted in a significant reduction of circulating myeloid cells (CD11b+) and intratumoral monocytic MDSCs (Ly6C+). p38 inhibition, in combination with chemotherapy, significantly improves overall survival in a PDAC GEMM.

Conclusions: These findings provide important mechanistic data to explore p38 MAPK inhibition to target the fibrotic stroma and reduce immunosuppressive myeloid levels in tumors and provide compelling preclinical evidence to combine pexmetinib with chemotherapy to improve overall survival in PDAC.

Citation Format: Samara Singh, Austin R. Dosch, Siddharth Mehra, Iago de Castro Silva, Anna Bianchi, Vanessa Tonin Garrido, Nilesh Deshpande, Zhiqun Zhou, Jashodeep Datta, Nagaraj Nagathihalli, Nipun Merchant. Targeting stromal-specific p38 MAPK signaling to stifle inflammatory reprogramming of cancer-associated fibroblasts in pancreatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1565.

Detecting hypodiploidy with endoreduplication and masked hypodiploidy in B-cell acute lymphoblastic leukemia using multicolor flow cytometry

BACKGROUND

Multicolor flow cytometry-based DNA-ploidy (MFC-ploidy) analysis is a simple, sensitive, and popular method for ploidy analysis in B-cell acute lymphoblastic leukemia (B-ALL). However, the utility of MFC-ploidy in the detection of B-ALL with endoreduplication or masked hypodiploidy has not been reported. Herein, we studied the patterns of MFC-ploidy assessment and its utility to detect B-ALL with hypodiploidy and endoreduplication.

METHODS

MFC-ploidy analysis was performed using FxCycle Violet-dye-based method, and cytogenetic ploidy was evaluated using chromosomal-counting and FISH analysis. A total of 20 B-ALL cases with endoreduplication were studied for the patterns of MFC-ploidy analysis and compared with 250 patients with hyperdiploidy and 11 cases with pure hypodiploidy.

RESULTS

All B-ALL with endoreduplication revealed two distinct peaks (populations) on MFC-ploidy analysis: the first (hypodiploid) peak (median-DNA-index [DI], 0.82; range, 0.6-0.95) and the second (hyperdiploid) peak with almost twice DI (median-DI, 1.53; range, 1.14-1.75). Cytogenetic findings were available in 19 cases and confirmed hypodiploidy with endoreduplication in 13/19 (68.4%) and only hypodiploidy in 3/19 cases. The remaining three cases showed hyperdiploid blasts in cytogenetic studies. Of these three, two cases had <10% blasts population with hypodiploidy. Thus, masked-hypodiploidy could be diagnosed correctly in 3/19 cases on MFC-ploidy analysis.

CONCLUSION

MFC-ploidy analysis shows a characteristic pattern of DNA-ploidy in samples with endoreduplication. It allows the distinction between samples with masked hypodiploidy from true hyperdiploidy. An integrated approach involving cytogenetic and MFC-ploidy detection is very helpful in the risk stratification of B-ALL in routine clinical practice.

Critical Role of Flow Cytometric Immunophenotyping in the Diagnosis, Subtyping, and Staging of T-Cell/NK-Cell Non-Hodgkin's Lymphoma in Real-World Practice: A Study of 232 Cases From a Tertiary Cancer Center in India

Background

T-cell/NK-cell non-Hodgkin’s lymphoma (T/NK-NHL) is an uncommon heterogeneous group of diseases. The current classification of T/NK-NHL is mainly based on histopathology and immunohistochemistry. In practice, however, the lack of unique histopathological patterns, overlapping cytomorphology, immunophenotypic complexity, inadequate panels, and diverse clinical presentations pose a great challenge. Flow cytometric immunophenotyping (FCI) is a gold standard for the diagnosis, subtyping, and monitoring of many hematological neoplasms. However, studies emphasizing the role of FCI in the diagnosis and staging of T/NK-NHL in real-world practice are scarce.

Methods

We included T-cell non-Hodgkin’s lymphoma (T-NHL) patients evaluated for the diagnosis and/or staging of T/NK-NHL using FCI between 2014 and 2020. We studied the utility of FCI in the diagnosis and subtyping of T/NK-NHL and correlated the FCI findings with the results of histopathology/immunohistochemistry. For correlation purposes, patients were categorized under definitive diagnosis and subtyping, inadequate subtyping, inadequate diagnosis, and misdiagnosis based on the findings of each technique.

Results

A total of 232 patients were diagnosed with T/NK-NHL. FCI findings provided definitive diagnoses in 198 patients and subtyping in 187/198 (95.45%) patients. The correlation between FCI and histopathological/immunohistochemistry results (n = 150) demonstrated an agreement on the diagnosis and subtyping in 69/150 (46%) patients. Of the remaining cases, the diagnosis and subtyping were inadequate in 64/150 (42.7%), and 14/150 (9.33%) were misdiagnosed on histopathology/immunohistochemistry results. FCI provided definitive diagnosis and subtyping in 51/64 (79.7%) patients. Among these, 13 patients diagnosed with peripheral T-cell lymphoma not-otherwise-specified were reclassified (angioimmunoblastic T-cell lymphoma (AITL)-11 and prolymphocytic leukemia-2) on FCI. It corrected the diagnosis in 14 patients that were misdiagnosed (6 B-cell NHL (B-NHL), 3 Hodgkin’s lymphoma, 1 acute leukemia, and 1 subcutaneous panniculitis-like T-cell lymphoma) and misclassified (3 T-NHL) on histopathological results. AITL was the commonest T-NHL misclassified on histopathological results. FCI also confirmed the definite involvement in 7/83 (8.4%) and 27/83 (32.5%) bone marrow (BM) samples reported as suspicious and uninvolved, respectively, on histopathological evaluation.

Conclusion

AITL was the most frequently diagnosed T/NK-NHL in this study. FCI provided a distinct advantage in detecting BM involvement by T/NK-NHL, especially in patients with low-level involvement. Overall, our study concluded that FCI plays a critical role in the diagnosis, subtyping, and staging of T/NK-NHL in real-world practice.

Improved protocol for plasma microRNA extraction and comparison of commercial kits

Introduction

MicroRNAs are small, non-coding RNA molecules that are becoming popular biomarkers in several diseases. However, their low abundance in serum/plasma poses a challenge in exploiting their potential in clinics. Several commercial kits are available for rapid isolation of microRNA from plasma. However, reports guiding the selection of appropriate kits to study downstream assays are scarce. Hence, we compared four commercial kits to evaluate microRNA-extraction from plasma and provided a modified protocol that further improved the superior kit's performance.

Materials and methods

We compared four kits (miRNeasy Serum/Plasma, miRNeasy Mini Kit from Qiagen; RNA-isolation, and Absolutely-RNA MicroRNA Kit from Agilent technologies) for quality and quantity of microRNA isolated, extraction efficiency, and cost-effectiveness. Bioanalyzer-based Agilent Small RNA kit was used to evaluate quality and quantity of microRNA. Extraction efficiency was evaluated by detection of four endogenous control microRNA using real-time-PCR. Further, we modified the manufacturer's protocol for miRNeasy Serum/Plasma kit to improve yield.

Results

miRNeasy Serum/Plasma kit outperformed the other three kits in microRNA-quality (P < 0.005) and yielded maximum microRNA-quantity. Recovery of endogenous control microRNA i.e. hsa-miR-24-3p, hsa-miR-191-5p, hsa-miR-423-5p and hsa-miR-484 was higher as well. Modification with the inclusion of a double elution step enhanced yield of microRNA extracted with miRNeasy Serum/Plasma kit significantly (P < 0.001).

Conclusion

We demonstrated that miRNeasy Serum/Plasma kit outperforms other kits and can be reliably used with a limited plasma quantity. We have provided a modified microRNA-extraction protocol with improved microRNA output for downstream analyses.

Comprehensive immune cell profiling depicts an early immune response associated with severe coronavirus disease 2019 in cancer patients

Recent studies have highlighted multiple immune perturbations related to severe acute respiratory syndrome coronavirus 2 infection-associated respiratory disease [coronavirus disease 2019 (COVID-19)]. Some of them were associated with immunopathogenesis of severe COVID-19. However, reports on immunological indicators of severe COVID-19 in the early phase of infection in patients with comorbidities such as cancer are scarce. We prospectively studied about 200 immune response parameters, including a comprehensive immune-cell profile, inflammatory cytokines and other parameters, in 95 patients with COVID-19 (37 cancer patients without active disease and intensive chemo/immunotherapy, 58 patients without cancer) and 21 healthy donors. Of 95 patients, 41 had severe disease, and the remaining 54 were categorized as having a nonsevere disease. We evaluated the association of immune response parameters with severe COVID-19. By principal component analysis, three immune signatures defining characteristic immune responses in COVID-19 patients were found. Immune cell perturbations, in particular, decreased levels of circulating dendritic cells (DCs) along with reduced levels of CD4 T-cell subsets such as regulatory T cells (T_regs ), type 1 T helper (Th1) and Th9; additionally, relative expansion of effector natural killer (NK) cells were significantly associated with severe COVID-19. Compared with patients without cancer, the levels of terminal effector CD4 T cells, T_regs , Th9, effector NK cells, B cells, intermediate-type monocytes and myeloid DCs were significantly lower in cancer patients with mild and severe COVID-19. We concluded that severely depleted circulating myeloid DCs and helper T subsets in the initial phase of infection were strongly associated with severe COVID-19 independent of age, type of comorbidity and other parameters. Thus, our study describes the early immune response associated with severe COVID-19 in cancer patients without intensive chemo/immunotherapy.

Mimics and artefacts of measurable residual disease in a highly sensitive multicolour flow cytometry assay for B-lymphoblastic leukaemia/lymphoma: critical consideration for analysis of measurable residual disease

High-sensitivity multicolour flow cytometry (MFC)-based B-lymphoblastic leukaemia (B-ALL) measurable residual disease (BMRD) assay is increasingly being used in clinical practice. Herein, we describe six consistently present low-level populations immunophenotypically mimicking abnormal B-ALL blasts in 441 BMRD samples from 301 children. These included CD19⁺ CD123⁺ plasmacytoid dendritic cells differentiating from lymphoid precursors, CD10⁺ transitional B cells with CD10⁺ /CD38dim-to-negative/CD20bright/CD45bright phenotype, CD19⁺ natural killer (NK) cells, CD73bright/CD10⁺ mesenchymal stromal/stem cells, CD73bright/CD34⁺ endothelial cells, and a CD34⁺ CD38dim-to-negative/CD10^- /CD20bright/CD45bright subset of mature B cells. We provide the proportions, comprehensive immunophenotype, and practical clues for proper identification of these low-level populations. Knowledge regarding the presence and immunophenotype of these mimics is essential for accurate interpretation in high-sensitivity MFC-BMRD analysis.

Mast cell differentiation of leukemic blasts in diverse myeloid neoplasms: A potential pre-myelomastocytic leukemia condition

INTRODUCTION

Myeloid neoplasm with blasts showing mast cell (MC)-differentiation and MC-component less than 10% of all nucleated cells but not fulfilling the criteria for systemic mastocytosis with associated hematological neoplasm (SM-AHN) or myelomastocytic leukemia (MML) has not been described in the literature. Herein, we report a study of diverse myeloid malignancies with blasts showing MC-differentiation but not meeting the criteria for SM-AHN or MML. We also evaluated the utility of flow-cytometric immunophenotyping (FCI) in the characterization of immature-MCs (iMCs).

METHODS

We identified nine patients of myeloid neoplasms and studied their morphological, FCI, immunohistochemistry, cytogenetic and molecular characteristics. We also compared the immunophenotypic features of MCs from patient samples with control samples.

RESULTS

The study included patients with newly-diagnosed acute myeloid leukemia (n = 4), chronic myelomonocytic leukemia (n = 1), and chronic myeloid leukemia on follow-up (n = 4) showing MC differentiation in leukemic-blasts. These patients had mildly increased MCs (range, 0.5%-3%) in bone-marrow morphology, including immature-forms and did not meet the criteria for either SM-AHN or MML. On FCI, iMCs were positive for bright-CD117, heterogeneous-CD34, dim-to-negative-HLADR, and moderate-CD203c expression. Expression-levels of CD123 and CD38 were higher (p < 0.001) but CD33 and CD45 were lower in iMCs compared to mature-MC from control samples (p = 0.019 and p = 0.0037).

CONCLUSION

We reported a rare finding of MC differentiation of leukemic blasts in diverse myeloid neoplasms and proposed it as a potential pre-myelomastocytic leukemia condition. We described the distinct immunophenotypic signature of immature-MCs using commonly used markers and highlighted the utility of FCI for the diagnosis of this entity.

Flow cytometric evaluation of CD38 expression levels in the newly diagnosed T-cell acute lymphoblastic leukemia and the effect of chemotherapy on its expression in measurable residual disease, refractory disease and relapsed disease: an implication for anti-CD38 immunotherapy

Background

Recently, anti-CD38 monoclonal antibody (Mab) therapy has become a focus of attention as an additional/alternative option for many hematological neoplasms including T-cell acute lymphoblastic leukemia (T-ALL). It has been shown that antitumor efficacy of anti-CD38-Mab depends on the level of CD38 expression on tumor cells. Reports on CD38 expression in T-ALL are scarce, and data on the effect of cytotoxic chemotherapy on CD38 expression are limited to very few samples. Moreover, it lacks entirely in refractory disease and in adult T-ALL. We report the flow cytometric evaluation of CD38 expression in T-ALL blasts at diagnosis and the effect of cytotoxic chemotherapy on its expression in measurable residual disease (MRD), refractory disease (MRD≥5%), and relapsed disease in a large cohort of T-ALL.

Methods

The study included 347 samples (188 diagnostic, 100 MRD, 24 refractory and 35 relapse samples) from 196 (children: 85; adolescents/adults: 111) patients with T-ALL. CD38-positive blasts percentages (CD38-PBPs) and expression-intensity (mean fluorescent intensity, CD38-MFI) were studied using multicolor flow cytometry (MFC). MFC-based MRD was performed at the end-of-induction (EOI-MRD, day 30–35) and end-of-consolidation (EOC-MRD, day 78–85) subsequent follow-up (SFU-MRD) points.

Results

Patients were classified into early thymic precursor subtype of T-ALL (ETPALL, 54/188, 28.7%), and non-ETPALL (134/188, 71.3%). Of 188, EOI-MRD assessment was available in 152, EOC-MRD was available in 96 and SFU-MRD was available in 14 patients. CD38 was found positive in 97.9% (184/188) of diagnostic, 88.7% (110/124) MRD (including 24-refractory) and 82.9% (29/35) relapsed samples. Median (95% CI) of CD38-PBPs/MFI in diagnostic, MRD, refractory, and relapsed T-ALL samples were, respectively, 85.9% (82.10%–89.91%)/4.2 (3.88–4.47), 74.0% (58.87%–83.88%)/4.6 (3.67–6.81), 79.6% (65.25%–96.11%)/4.6 (3.33–8.47) and 85.2% (74.48%–93.01%)/5.6 (4.14–8.99). No significant difference was noted in CD38 expression between pediatric versus adult and patients with ETPALL versus non-ETPALL. No change was observed in CD38-MFI between diagnostic versus MRD and diagnostic versus relapsed paired samples. However, we noticed a mild drop in the CD38-PBPs in MRD samples compared with the diagnostic samples (p=0.016).

Conclusion

We report an in-depth analysis of CD38 expression in a large cohort of T-ALL at diagnosis, during chemotherapy, and at relapse. Our data demonstrated that CD38 is robustly expressed in T-ALL blasts with a little effect of cytotoxic chemotherapy making it a potentially effective target for antiCD38-Mab therapy.

Engineered Multifunctional Nano- and Biological Materials for Cancer Immunotherapy

Cancer immunotherapy is set to emerge as the future of cancer therapy. However, recent immunotherapy trials in different cancers have yielded sub-optimal results, with durable responses seen in only a small fraction of patients. Engineered multifunctional nanomaterials and biological materials are versatile platforms that can elicit strong immune responses and improve anti-cancer efficacy when applied to cancer immunotherapy. While there are traditional systems such as polymer- and lipid-based nanoparticles, there is a wide variety of other materials with inherent and additive properties that can allow for more potent activation of the immune system. By synthesizing and applying multifunctional strategies, it allows for a more extensive and more effective repertoire of tools to use in the wide variety of situations that cancer presents itself. Here, several types of nanoscale and biological material strategies and platforms that provide their inherent benefits for targeting and activating multiple aspects of the immune system are discussed. Overall, this review aims to provide a comprehensive understanding of recent advances in the field of multifunctional cancer immunotherapy and trends that pave the way for more diverse and tactical regression of tumors through soliciting responses by either the adaptive or innate immune system, and even both simultaneously.

Expression of CD304/neuropilin-1 in adult b-cell lymphoblastic leukemia/lymphoma and its utility for the measurable residual disease assessment

INTRODUCTION

Many new markers are being evaluated to increase the sensitivity and applicability of multicolor flow cytometry (MFC)-based measurable residual disease (MRD) monitoring. However, most of the studies are limited to childhood B-cell lymphoblastic leukemia/lymphoma (B-ALL), and reports in adult B-ALL are extremely scarce and limited to small cohorts. We studied the expression of CD304/neuropilin-1 in a large cohort of adult B-ALL patients and evaluated its practical utility in MFC-based MRD analysis.

METHODS

CD304 was studied in blasts from adult B-ALL patients and normal precursor B cells (NPBC) from non-B-ALL bone marrow samples using MFC. CD304 expression intensity and pattern were studied with normalized-mean fluorescent intensity (nMFI) and coefficient of variation of immunofluorescence (CVIF), respectively. MFC-based MRD was performed at end of induction (EOI; day-35), end of consolidation (EOC; day 78-80), and subsequent follow-up (SFU) time points.

RESULTS

CD304 was positive in 120/214(56.07%) and was significantly associated with BCR-ABL1 fusion (P = .001). EOI-MRD and EOC-MRD were positive in 129/214(60.3%) and 50/81(61.72%), respectively. CD304 was positive in a significant percentage of EOI (48%, 62/129) and EOC (52%, 26/50) MRD-positive B-ALL samples. Its expression was retained, lost, and gained in 73.7%, 26.3%, and 11.3% of EOI-MRD and 85.7%, 14.3%, and none of EOC-MRD samples, respectively. Low-level MRD (<0.01%) was detectable in 34 of all (EOI + EOC + SFU = 189) MRD-positive samples, and CD304 was found useful in 50% of these samples.

CONCLUSION

CD304 is commonly expressed in adult B-ALL and clearly distinguish B-ALL blasts from normal precursor B cells. It is a stable MRD marker and distinctly useful in the detection of MFC-based MRD monitoring, especially in high-sensitivity MRD assay.

Clinical impact of panel-based error-corrected next generation sequencing versus flow cytometry to detect measurable residual disease (MRD) in acute myeloid leukemia (AML)

We accrued 201 patients of adult AML treated with conventional therapy, in morphological remission, and evaluated MRD using sensitive error-corrected next generation sequencing (NGS-MRD) and multiparameter flow cytometry (FCM-MRD) at the end of induction (PI) and consolidation (PC). Nearly 71% of patients were PI NGS-MRD⁺ and 40.9% PC NGS-MRD⁺ (median VAF 0.76%). NGS-MRD⁺ patients had a significantly higher cumulative incidence of relapse (p = 0.003), inferior overall survival (p = 0.001) and relapse free survival (p < 0.001) as compared to NGS-MRD^- patients. NGS-MRD was predictive of inferior outcome in intermediate cytogenetic risk and demonstrated potential in favorable cytogenetic risk AML. PI NGS-MRD^- patients had a significantly improved survival as compared to patients who became NGS-MRD^- subsequently indicating that kinetics of NGS-MRD clearance was of paramount importance. NGS-MRD identified over 80% of cases identified by flow cytometry at PI time point whereas FCM identified 49.3% identified by NGS. Only a fraction of cases were NGS-MRD^- but FCM-MRD⁺. NGS-MRD provided additional information of the risk of relapse when compared to FCM-MRD. We demonstrate a widely applicable, scalable NGS-MRD approach that is clinically informative and synergistic to FCM-MRD in AML treated with conventional therapies. Maximum clinical utility may be leveraged by combining FCM and NGS-MRD modalities.

Immunophenotypic shift in the B-cell precursors from regenerating bone marrow samples: A critical consideration for measurable residual disease assessment in B-lymphoblastic leukemia

Accurate knowledge of expression patterns/levels of commonly used MRD markers in regenerative normal-B-cell-precursors (BCP) is highly desirable to distinguish leukemic-blasts from regenerative-BCP for multicolor flow cytometry (MFC)-based measurable residual disease (MRD) assessment in B-lymphoblastic leukemia (B-ALL). However, the data highlighting therapy-related immunophenotypic-shift in regenerative-BCPs is scarce and limited to small cohort. Herein, we report the in-depth evaluation of immunophenotypic shift in regenerative-BCPs from a large cohort of BALL-MRD samples. Ten-color MFC-MRD analysis was performed in pediatric-BALL at the end-of-induction (EOI), end-of-consolidation (EOC), and subsequent-follow-up (SFU) time-points. We studied normalized-mean fluorescent intensity (nMFI) and coefficient-of-variation of immunofluorescence (CVIF) of CD10, CD19, CD20, CD34, CD38, and CD45 expression in regenerative-BCP (early, BCP1 and late, BCP2) from 200 BALL-MRD samples, and compared them with BCP from 15 regenerating control (RC) TALL-MRD samples and 20 treatment-naïve bone-marrow control (TNSC) samples. Regenerative-BCP1 showed downregulation in CD10 and CD34 expression with increased CVIF and reduced nMFI (p < 0.001), upregulation of CD20 with increased nMFI (p = 0.014) and heterogeneous CD45 expression with increased CVIF (p < 0.001). Immunophenotypic shift was less pronounced in the BCP2 compared to BCP1 compartment with increased CVIF in all but CD45 (p < 0.05) and reduced nMFI only in CD45 expression (p = 0.005). Downregulation of CD10/CD34 and upregulation of CD20 was higher at EOI than EOC and SFU time-points (p < 0.001). Regenerative-BCPs are characterized by the significant immunophenotypic shift in commonly used B-ALL-MRD markers, especially CD10 and CD34 expression, as compared to treatment-naïve BCPs. Therefore, the templates/database for BMRD analysis must be developed using regenerative-BCP.

Utility of CD36 as a novel addition to the immunophenotypic signature of RAM-phenotype acute myeloid leukemia and study of its clinicopathological characteristics

INTRODUCTION

In 2016, Children Oncology Group (COG) described a new high-risk subtype of acute myeloid leukemia (AML) with a distinct immunophenotypic-signature, RAM-phenotype (RAM-AML). Data on clinical and laboratory features of RAM-AML are still limited to COG report only. Herein, we report the clinicopathological characteristics and detailed immunophenotypic features of RAM-AML patients. In COG report, 38% of RAM-AML belonged to acute megakaryoblastic leukemia (AMKL)-subtype. Hence, we further compared the immunophenotypic features RAM-AML with non-RAM-AMKL diagnosed during the same study period.

METHODS

We included RAM-AML and non-RAM AMKL patients diagnosed between January 2017 and December 2019. We studied their morphological, cytochemical, immunophenotyping, cytogenetic, and molecular characteristics. Mean fluorescent intensity (MFI) and expression-pattern of immunophenotypic markers of RAM-AML were compared with non-RAM AMKLs patients.

RESULTS

We identified 11 RAM-AML (1%) and 21 non-RAM AMKL (1.9%) patients in 1102 pediatric-AML patients. Seven of 11 (63.64%) patients belonged to FAB-M7-subtype. CD56, CD117, and CD33 demonstrated overexpression, whereas CD45 and CD38 showed under-expression in RAM-AML patients. CD36 was consistently negative in RAM-AML, whereas moderate-bright positive in non-RAM AMKLs patients (p < 0.0001). On principle component analysis, addition of CD36 enhanced the visual-separation between RAM-AML and non-RAM AMKL clusters. Cytogenetic and molecular studies did not show any recurrent abnormality; however, RNA-sequencing study revealed CBFA2T3-GLIS2-fusion in three of seven (42.8%) RAM-AML patients.

CONCLUSION

We report the clinicopathological characteristics and the detailed immunophenotypic profile in the world's second series of RAM-AML patients. We further report a novel finding of CD36-negative expression as an additional parameter to the multidimensional immunophenotypic signature of this entity.

Supramolecular Polysaccharide Nanotheranostics that Inhibit Cancer Cells Growth and Monitor Targeted Therapy Response

Targeted anticancer therapies directed against specific molecular drivers of tumors are emerging as effective treatment strategies, however, monitoring their response is still challenging. Current clinical imaging techniques that measure either morphological or metabolic changes in the tumor are not always indicative of clinical outcome due to delayed or variable responses. Here, dual-stage polysaccharide-based supramolecular nanotheranostics (SPN) were designed that enable co-delivery of kinase inhibitor and an activatable imaging probe.

Methods: The SPNs were prepared by supramolecular assembly of two components, polysaccharide construct conjugated with kinase inhibitor-function activatable probe and kinase inhibitor- β-cyclodextrin conjugate. Physiochemical characterization of SPNs including size, stability, zeta potential and pH-responsiveness of the assembly was performed. The efficacy of SPNs in inducing cancer cell death by inhibition of kinase signaling and imaging the response was evaluated in murine BRAFV^600E melanoma (D4M) and triple-negative breast cancer (4T1) cell lines. Finally, the in vivo efficacy was investigated in D4M melanoma tumor model.

Results: The polysaccharide-constructs along with kinase inhibitor- β-cyclodextrin conjugates self-assemble to produce SPNs of around 200 nm in diameter and were stable for over a week under physiologically relevant conditions. The SPNs exhibited enhanced cytotoxic effect and significant inhibition of kinase signaling as compared to the free inhibitor. In vitro imaging studies confirmed their enzyme-activatable therapy response tracking abilities both in cancer cells and tumor spheroids. Furthermore, SPN treated mice exhibited better tumor growth inhibition as compared to the control groups and therapy response could be imaged at both early (24-48h) and later time points.

Conclusion: These findings demonstrate that the supramolecular polysaccharide nanotheranostics can not only inhibit kinase signaling pathway in aggressive tumor, but also monitor targeted therapy response early.

Post-induction Measurable Residual Disease Using Multicolor Flow Cytometry Is Strongly Predictive of Inferior Clinical Outcome in the Real-Life Management of Childhood T-Cell Acute Lymphoblastic Leukemia: A Study of 256 Patients

Background: Measurable/minimal residual disease (MRD) status is suggested as a powerful indicator of clinical-outcome in T-cell lymphoblastic leukemia/lymphoma (T-ALL). Contrary to B-cell ALL, reports on T-ALL MRD are limited and mostly based on molecular methods, mainly from developed countries. Multicolor flow cytometry (MFC)-based T-ALL studies are very few. Clinically relevant cut-off levels and ideal time-point for MRD assessment are still inconclusive. In view of lack of T-ALL MRD data from the developing world, we evaluated the prognostic value of MFC-based post-induction (PI)-MRD assessment in T-ALL in the context of standard practice. Methods: We included 256 childhood-T-ALL patients (age < 15 years) treated with a modified-MCP841 protocol, which uses high-dose cytarabine during consolidation, as a part of standard hospital practice. MRD was studied using 10-color 11-antibody MFC with any level of detectable disease being considered positive. Post-induction (PI)-MRD was available in all patients, and post-consolidation (PC) MRD was available mostly in PI-MRD-positive patients (n = 88). Results: Three years cumulative-incidence-of-relapse (3years-CIR) in PI-MRD-positive patients was inferior to negative patients (46.3% vs. 18.4%). The median relapse-free-survival (RFS), event-free-survival (EFS) and overall-survival (OS) with hazard ratio (HR) of PI-MRD-positive patients were 21.4 months vs not reached (p < 0.0001, HR-4.7), 21.6 months vs. not-reached (p = 0.0003, HR-2.01) and 37.3 months vs. not reached (p = 0.026, HR-1.64) respectively. RFS, EFS and OS of patients with PI-MRD<0.01% (n = 17) were as inferior as PI-MRD ≥ 0.01% in comparison with MRD-negative patients with HR of 4.7 (p < 0.0001), 2.45 (p = 0.0003), and 2.5 (p = 0.029), respectively. Three-years-CIR of patients with hyperleukocytosis (≥100 × 109/L) was also higher (50.5 vs. 27.6%) with inferior RFS, EFS, and OS. Among PI-MRD-positive patients, 3years-CIR, RFS, EFS, and OS of PC-MRD-positive were also inferior to that of negative patients. On multivariate analysis any-level detectable PI-MRD and hyperleukocytosis remained independently associated with inferior RFS, EFS, and OS. A combination of PI-MRD-positive status and hyperleukocytosis identified the patients with the worst clinical outcomes. Conclusion: Detectable PI-MRD using MFC was found to be the strong predictive factor of inferior clinical outcome in T-ALL patients. The combination of PI-MRD status and hyperleukocytosis provides the most influential tool for the management of T-ALL in resource constrained settings from developing world.

Utility of Immunophenotypic Measurable Residual Disease in Adult Acute Myeloid Leukemia-Real-World Context

Introduction: One of the mainstays of chemotherapy in acute myeloid leukemia (AML) is induction with a goal to achieve morphological complete remission (CR). However, not all patients by this remission criterion achieve long-term remission and a subset relapse. This relapse is explained by the presence of measurable residual disease (MRD).

Methods: We accrued 451 consecutive patients of adult AML (from March 2012 to December 2017) after informed consent. All patients received standard chemotherapy. MRD testing was done at post-induction and, if feasible, post-consolidation using 8- and later 10-color FCM. Analysis of MRD was done using a combination of difference from normal and leukemia-associated immunophenotype approaches. Conventional karyotyping and FISH were done as per standard recommendations, and patients were classified into favorable, intermediate, and poor cytogenetic risk groups. The presence of FLT3-ITD, NPM1, and CEBPA mutations was detected by a fragment length analysis-based assay.

Results: As compared to Western data, our cohort of patients was younger with a median age of 35 years. There were 62 induction deaths in this cohort (13.7%), and 77 patients (17.1%) were not in morphological remission. The median follow-up was 26.0 months. Poor-risk cytogenetics and the presence of FLT3-ITD were significantly associated with inferior outcome. The presence of post-induction MRD assessment was significantly associated with adverse outcome with respect to OS (p = 0.01) as well as RFS (p = 0.004). Among established genetic subgroups, detection of MRD in intermediate cytogenetic and NPM1 mutated groups was also highly predictive of inferior outcome. On multivariate analysis, immunophenotypic MRD at the end of induction and FLT3-ITD emerged as independent prognostic factors predictive for outcome.

Conclusion: This is the first data from a resource-constrained real-world setting demonstrating the utility of AML MRD as well as long-term outcome of AML. Our data is in agreement with other studies that determination of MRD is extremely important in predicting outcome. AML MRD is a very useful guide for guiding post-remission strategies in AML and should be incorporated into routine treatment algorithms.

Some Aspects of Pituitary Function after Neuroadenolysis in Patients with Metastatic Cancer

The effects of neuroadenolysis on plasma titres of β-endorphin, β-lipotropin, ACTH, TSH and prolactin have been investigated in five patients with metastatic cancer who responded to the treatment and have been in remission for more than four years and in five others who were undergoing the treatment for the first time for pain due to cancer metastases. β-endorphin, β-lipotropin and ACTH titres were within the normal ranges of values in both categories of patients but post-neuroadenolysis titres of these peptides were higher than those before the treatment. The ability to secrete TSH and prolactin and to respond to thyroid stimulating hormone releasing hormone (TRH) remains intact following the treatment. However, whereas basal TSH titres and response to TRH was lower in the majority of patients, no such effect was observed on prolactin secretion. Plasma titres of prolactin and TSH were below the sensitivity of the method in the five patients who are in remission for more than four years. These preliminary findings suggest that neuroadenolysis probably affects some mechanism(s) associated with the control of β-endorphin, β-lipotropin and ACTH synthesis.

Hormone Synthesis by Primary Breast Carcinomas and Prognosis in Human Breast Cancer

The ability of human breast carcinomas to convert pregnenolone to progesterone and dehydroepiandrosterone to Δ4-androstene-3,17-dione (Δ4) was investigated as a potential aid for prognosis, and the following observations were recorded. 1. Neither the amounts of progesterone or Δ4 synthesized nor Δ4/progesterone ratios correlated with tumour size or lymph node involvement. 2. Δ4 synthesis was lower in carcinomas from patients who had recurrences within 2 years of mastectomy than in carcinomas from those who remained free of metastases. 3. Life table analysis of the results indicated that these parameters appeared unlikely to be useful aids for prognosis.

Effects of Opiates and Naloxone on Certain Enzymes of Carbohydrate Metabolism in Human Breast Carcinomas

The effects of administration of opiates and naloxone on the activities of PFK, 6PGDH and α-GPDH and α-GPDH/6PGDH ratios in human breast carcinomas were investigated in patients awaiting mastectomy. Injection of naloxone or fentanyl into an antecubital vein resulted in a statistically significant reduction in the activity of α-GPDH. Fentanyl was also effective in reducing the activity of 6PGDH. Injection of morphine into a branch of the internal mammary artery during mastectomy failed to induce changes in the activities of any of the enzymes but injection of naloxone resulted in a significant rise in the activity of 6PGDH. It is postulated that these alterations in the activities might not be associated with the binding of these drugs to opiate receptor proteins in the carcinoma. Furthermore opiate agonists or antagonists might not produce the required changes in the activities of any of the enzymes.

Evaluation of new markers for minimal residual disease monitoring in B-cell precursor acute lymphoblastic leukemia: CD73 and CD86 are the most relevant new markers to increase the efficacy of MRD 2016; 00B: 000-000

BACKGROUND

Multiparametric flow cytometry (MFC) is a popular technique for minimal residual disease (MRD) analysis. However, its applicability is still limited to 90% of B-cell precursor acute lymphoblastic leukemia (BCPALL) due to two major issues, i.e. a proportion of cases do not express adequate leukemia associated immunophenotype (LAIPs) with currently used markers and drug-induced antigen modulation. Hence, the incorporation of additional reliable markers is required for the further improvement of MFC-based MRD evaluation. We studied the utility of new markers in improvising MFC-based MRD detection in BCPALL.

METHODS

Expression-patterns of six new markers, i.e. CD24, CD44, CD72, CD73, CD86, and CD200 were studied in leukemic-blasts from ninety childhood BCPALL patients and in hematogones from 20 uninvolved staging bone marrow (BM) and ten postinduction non-BCPALL BM samples using eight-color MFC. The utility of these new markers in the day 35 postinduction MRD evaluation was determined.

RESULTS

Frequencies of LAIPs of CD73, CD86, CD72, CD44, CD200, and CD24 in diagnostic samples were 76.7, 56.7, 55.6, 50, 28.9, and 20%, respectively. Differential expression of all new markers was highly significant (P < 0.01) between early (CD10+ CD19+ CD34+) hematogones, late (CD10+ CD19+ CD34-) hematogones and BCPALL blasts except between early hematogones and BCPALL blasts for CD200 (P = 0.1). In MRD-positive samples, CD73 showed the maximum (83%) frequency of LAIP and CD86 showed the highest (100%) stability of aberrant expression. Inclusion of CD73 and CD86 increased the applicability of MFC-MRD assay to 98.9% MRD samples.

CONCLUSION

CD73 and CD86 are the most relevant markers to incorporate in the routine MRD evaluation of BCPALL. © 2016 International Clinical Cytometry Society.

Molecular ultrasound imaging: current status and future directions

Targeted contrast-enhanced ultrasound (molecular ultrasound) is an emerging imaging strategy that combines ultrasound technology with novel molecularly-targeted ultrasound contrast agents for assessing biological processes at the molecular level. Molecular ultrasound contrast agents are nano- or micro-sized particles that are targeted to specific molecular markers by adding high-affinity binding ligands onto the surface of the particles. Following intravenous administration, these targeted ultrasound contrast agents accumulate at tissue sites overexpressing specific molecular markers, thereby enhancing the ultrasound imaging signal. High spatial and temporal resolution, real-time imaging, non-invasiveness, relatively low costs, lack of ionising irradiation and wide availability of ultrasound systems are advantages compared to other molecular imaging modalities. In this article we review current concepts and future directions of molecular ultrasound imaging, including different classes of molecular ultrasound contrast agents, ongoing technical developments of pre-clinical and clinical ultrasound systems, the potential of molecular ultrasound for imaging different diseases at the molecular level, and the translation of molecular ultrasound into the clinic.

Variability in platelet response to a single daily dose of 150 mg enteric coated aspirin in a high risk population

PURPOSE

Previous studies have reported inadequate anti-platelet effect in 0.4-35% of patients taking aspirin. Such studies have arbitrarily defined the terms "semi-responders", "non-responders" or "resistant" to variable doses of aspirin on the basis of absolute values derived from different ex-vivo platelet aggregation (PA) methods. Our objective was to define response to 150-mg dose of aspirin in terms of normally distributed values using an ex-vivo measure of PA in a population at high risk for vascular events.

METHODS

We prospectively studied high risk patients with either established coronary artery disease (CAD) or stroke or transient ischemic attack (TIA) or peripheral vascular disease or with multiple atherothrombotic risk factors like diabetes plus one of the following-- hypertension, increased total cholesterol, cigarette smoking, micro-albuminuria, low-high density lipoprotein (HDL), family history of CAD and receiving single 150 mg dose of aspirin daily. PA was assessed by chronolog lumi-aggregometer (490-2D) using arachidonic acid (AA) reagent.

RESULTS

130 patients were studied. The response of subjects to aspirin followed a normal, bell shaped distribution curve with a mean and standard deviation (S.D.) of 13.1 +/- 4.4%. 3.1% patients had PA values more than 2 S.D. of the mean, hence termed as hypo-responders to aspirin while another 3.1% patients had PA values less than 2 S.D. of the mean, hence termed as hyper-responders to aspirin.

CONCLUSION

There is minimal inter-individual variability in the response to aspirin when tested with AA as the reagent. The response to aspirin follows a normal Gaussian distribution. The prevalence of hypo-responders to aspirin in high risk population is only 3.1%. This is the first study to document "hypo" and "hyper-responders" to single daily dose of 150 mg aspirin. The clinical relevance of these findings remains to be determined.

Dynamics of FSH-induced follicular growth in subfertile women: relationship with age, insulin resistance, oocyte yield and anti-Mullerian hormone

BACKGROUND

During excess FSH treatment, different categories of follicles can be discerned: those responding and appearing to grow immediately (FolsS8) and those appearing subsequently during the follicular phase (Fols/d). These follicular categories were explored in cycles of assisted reproduction in the context of follicular biology, including primordial follicle pool (PFP) depletion, age, insulin resistance and potential markers.

METHODS

Follicular cohorts were examined in 365 conventional ART cycles and related to patient insulin sensitivity, plasma FSH and anti-Mullerian hormone (AMH).

RESULTS

Age had no influence upon the FolsS8 category but was associated with a significant (P < 0.005) decline in the Fols/d. In contrast, insulin-resistant polycystic ovary syndrome (IR-PCOS) showed a significant (P = 0.005) increase in FolsS8. Circulating AMH correlated strongly with oocyte yield and Fols/d.

CONCLUSION

Age showed little impact on the initial follicular cohort, but a significant impact upon the secondary cohort, while insulin resistance appeared to promote the former category alone. The disturbance to follicular dynamics and AMH in IR-PCOS reflected a larger stockpile of FSH-sensitive follicles. Circulating AMH appears to represent all categories of antral follicles observed.