Practical Application of Multivendor MRI-Based R2* Mapping for Liver Iron Quantification at 1.5 T and 3.0 T.

BACKGROUND: Recent multicenter, multivendor MRI-based R2* vs. liver iron concentration (LIC) calibrations (i.e., MCMV calibrations) may facilitate broad clinical dissemination of R2*-based LIC quantification. However, these calibrations are based on a centralized offline R2* reconstruction, and their applicability with vendor-provided R2* maps is unclear. PURPOSE: To determine R2* ranges of agreement between the centralized and three MRI vendors' R2* reconstructions. STUDY TYPE: Prospective. SUBJECTS: Two hundred and seven subjects (mean age 37.6 ± 19.6 years; 117 male) with known or suspected iron overload from four academic medical centers. FIELD STRENGTH/SEQUENCE: Standardized multiecho spoiled gradient echo sequence at 1.5 T and 3.0 T for R2* mapping and a multiple spin-echo sequence at 1.5 T for LIC quantification. MRI vendors: GE Healthcare, Philips Healthcare, and Siemens Healthineers. ASSESSMENT: R2* maps were generated using both the centralized and vendor reconstructions, and ranges of agreement were determined. R2*-LIC linear calibrations were determined for each site, field strength, and reconstruction and compared with the MCMV calibrations. STATISTICAL TESTS: Bland-Altman analysis to determine ranges of agreement. Linear regression, analysis of covariance F tests, and Tukey's multiple comparison testing to assess reproducibility of calibrations across sites and vendors. A P value <0.05 was considered significant. RESULTS: The upper limits of R2* ranges of agreement were approximately 500, 375, and 330 s-1 for GE, Philips, and Siemens reconstructions, respectively, at 1.5 T and approximately 700 and 800 s-1 for GE and Philips, respectively, at 3.0 T. Within the R2* ranges of agreement, vendor R2*-LIC calibrations demonstrated high reproducibility (no significant differences between slopes or intercepts; P ≥ 0.06) and agreed with the MCMV calibrations (overlapping 95% confidence intervals). DATA CONCLUSION: Based on the determined upper limits, R2* measurements obtained from vendor-provided R2* maps may be reliably and practically used to quantify LIC less than approximately 8-13 mg/g using the MCMV calibrations and similar acquisition parameters as this study. EVIDENCE LEVEL: 1 TECHNICAL EFFICACY: Stage 3.

Multicenter Reproducibility of Liver Iron Quantification with 1.5-T and 3.0-T MRI.

Background MRI is a standard of care tool to measure liver iron concentration (LIC). Compared with regulatory-approved R2 MRI, R2* MRI has superior speed and is available in most MRI scanners; however, the cross-vendor reproducibility of R2*-based LIC estimation remains unknown. Purpose To evaluate the reproducibility of LIC via single-breath-hold R2* MRI at both 1.5 T and 3.0 T with use of a multicenter, multivendor study. Materials and Methods Four academic medical centers using MRI scanners from three different vendors (three 1.5-T scanners, one 2.89-T scanner, and two 3.0-T scanners) participated in this prospective cross-sectional study. Participants with known or suspected liver iron overload were recruited to undergo multiecho gradient-echo MRI for R2* mapping at 1.5 T and 3.0 T (2.89 T or 3.0 T) on the same day. R2* maps were reconstructed from the multiecho images and analyzed at a single center. Reference LIC measurements were obtained with a commercial R2 MRI method performed using standardized 1.5-T spin-echo imaging. R2*-versus-LIC calibrations were generated across centers and field strengths using linear regression and compared using F tests. Receiver operating characteristic (ROC) curve analysis was used to determine the diagnostic performance of R2* MRI in the detection of clinically relevant LIC thresholds. Results A total of 207 participants (mean age, 38 years ± 20 [SD]; 117 male participants) were evaluated between March 2015 and September 2019. A linear relationship was confirmed between R2* and LIC. All calibrations within the same field strength were highly reproducible, showing no evidence of statistically significant center-specific differences (P > .43 across all comparisons). Calibrations for 1.5 T and 3.0 T were generated, as follows: for 1.5 T, LIC (in milligrams per gram [dry weight]) = -0.16 + 2.603 × 10-2 R2* (in seconds-1); for 2.89 T, LIC (in milligrams per gram) = -0.03 + 1.400 × 10-2 R2* (in seconds-1); for 3.0 T, LIC (in milligrams per gram) = -0.03 + 1.349 × 10-2 R2* (in seconds-1). Liver R2* had high diagnostic performance in the detection of clinically relevant LIC thresholds (area under the ROC curve, >0.98). Conclusion R2* MRI enabled accurate and reproducible quantification of liver iron overload over clinically relevant ranges of liver iron concentration (LIC). The data generated in this study provide the necessary calibrations for broad clinical dissemination of R2*-based LIC quantification. ClinicalTrials.gov registration no.: NCT02025543 © RSNA, 2022 Online supplemental material is available for this article.

Marrow-Derived Autologous Stromal Cells for the Restoration of Salivary Hypofunction (MARSH): A pilot, first-in-human study of interferon gamma-stimulated marrow mesenchymal stromal cells for treatment of radiation-induced xerostomia.

BACKGROUND AIMS: Xerostomia, or the feeling of dry mouth, is a significant side effect of radiation therapy for patients with head and neck cancer (HNC). Preliminary data suggest that mesenchymal stromal/stem cells (MSCs) can improve salivary function. We performed a first-in-human pilot study of interferon gamma (IFNγ)-stimulated autologous bone marrow-derived MSCs, or MSC(M), for the treatment of radiation-induced xerostomia (RIX). Here we present the primary safety and secondary efficacy endpoints. METHODS: A single-center pilot clinical trial was conducted investigating the safety and tolerability of autologous IFNγ-stimulated MSC(M). The study was conducted under an approved Food and Drug Administration Investigational New Drug application using an institutional review board-approved protocol (NCT04489732). Patients underwent iliac crest bone marrow aspirate and MSC(M) were isolated, cultured, stimulated with IFNγ and cryopreserved for later use. Banked cells were thawed and allowed to recover in culture before patients received a single injection of 10 × 106 MSC(M) into the right submandibular gland under ultrasound guidance. The primary objective was determination of safety and tolerability by evaluating dose-limiting toxicity (DLT). A DLT was defined as submandibular pain >5 on a standard 10-point pain scale or any serious adverse event (SAE) within 1 month after injection. Secondary objectives included analysis of efficacy as measured by salivary quantification and using three validated quality of life instruments. Quantitative results are reported as mean and standard deviation. RESULTS: Six patients with radiation-induced xerostomia who had completed radiation at least 2 years previously (average 7.8 years previously) were enrolled in the pilot study. The median age was 71 (61-74) years. Five (83%) patients were male. Five patients (83%) were treated with chemoradiation and one patient (17%) with radiation alone. Grade 1 pain was seen in 50% of patients after submandibular gland injection; all pain resolved within 4 days. No patients reported pain 1 month after injection, with no SAE or other DLTs reported 1 month after injection. The analysis of secondary endpoints demonstrated a trend of increased salivary production. Three patients (50%) had an increase in unstimulated saliva at 1 and 3 months after MSC(M) injection. Quality of life surveys also showed a trend toward improvement. CONCLUSIONS: Injection of autologous IFNγ-stimulated MSC(M) into a singular submandibular gland of patients with RIX is safe and well tolerated in this pilot study. A trend toward an improvement in secondary endpoints of salivary quantity and quality of life was observed. This first-in-human study provides support for further investigation into IFNγ-stimulated MSC(M) injected in both submandibular glands as an innovative approach to treat RIX and improve quality of life for patients with HNC.

Marrow-Derived Autologous Stromal Cells for the Restoration of Salivary Hypofunction (MARSH): Study protocol for a phase 1 dose-escalation trial of patients with xerostomia after radiation therapy for head and neck cancer: MARSH: Marrow-Derived Autologous Stromal Cells for the Restoration of Salivary Hypofunction.

BACKGROUND: Xerostomia, or dry mouth, is a common side effect of head and neck radiation. Current treatment options for radiation-induced xerostomia are generally supportive in nature. Adult stem cells are the ultimate source for replenishment of salivary gland tissue. Bone marrow-derived mesenchymal stromal cells (BM-MSCs) are a viable cell-based therapy for xerostomia. We have undertaken studies enabling U.S. Food and Drug Administration Investigational New Drug status, demonstrating the normal phenotype, intact functionality, and pro-growth secretome of interferon-γ (IFNγ)-stimulated BM-MSCs taken from patients with head and neck cancer who have undergone radiation ± chemotherapy. Here we present the protocol of MARSH, a first-in-human clinical trial of bone marrow-derived, IFNγ-activated BM-MSCs for the treatment of radiation-induced xerostomia. METHODS: This single-center phase 1 dose-escalation with expansion cohort, non-placebo-controlled study will assess the safety and tolerability of BM-MSCs for the treatment of radiation-induced xerostomia in patients who had head and neck cancer. The phase 1 dose-escalation study will be a 3 + 3 design with staggered enrollment. A total of 21 to 30 subjects (9 to 18 in phase 1 study, 12 in expansion cohort) will be enrolled. The primary endpoint is determining the recommended phase 2 dose (RP2D) of IFNγ-stimulated BM-MSCs to enable further studies on the efficacy of BM-MSCs. Patients' bone marrow will be aspirated, and BM-MSCs will be expanded, stimulated with IFNγ, and injected into the submandibular gland. The RP2D will be determined by dose-limiting toxicities occurring within 1 month of BM-MSC injection. Secondary outcomes of saliva amounts and composition, ultrasound of salivary glands, and quality of life surveys will be taken at 3-, 6-, 12-, and 24-month visits. DISCUSSION: Autotransplantation of IFNγ-stimulated BM-MSCs in salivary glands after radiation therapy or chemoradiation therapy may provide an innovative remedy to treat xerostomia and restore quality of life. This is the first therapy for radiation-induced xerostomia that may be curative. TRIAL REGISTRATION: World Health Organization International Clinical Trials Registry Platform: NCT04489732.

Sequencing of novel agents in relapsed/refractory B-cell acute lymphoblastic leukemia: Blinatumomab and inotuzumab ozogamicin may have comparable efficacy as first or second novel agent therapy in relapsed/refractory acute lymphoblastic leukemia.

BACKGROUND: The availability of novel agents (NAs), including blinatumomab and inotuzumab ozogamicin (InO), has improved the outcomes of patients with relapsed/refractory (RR) B-cell acute lymphoblastic leukemia (ALL). Because of the relative effectiveness, it is often a challenge for clinicians to determine how to best sequence these NAs with respect to efficacy and toxicity. METHODS: In this multicenter, retrospective study of patients with RR ALL treated with blinatumomab, InO, or both, their efficacy as a first or second NA was compared. RESULTS: Among 276 patients, 221 and 55 received blinatumomab and InO, respectively, as a first NA therapy. The complete remission (CR)/complete remission with incomplete count recovery (CRi) rate was 65% and 67% for the blinatumomab and InO groups, respectively (P = .73). The rate of treatment discontinuation due to adverse events was 4% and 7% in the blinatumomab and InO groups, respectively. Ninety-two patients (43%) in the blinatumomab group and 13 patients (29%) in the InO group proceeded with allogeneic hematopoietic stem cell transplantation. The median overall survival (OS) was 15 and 11.6 months in the blinatumomab and InO groups, respectively. A subset analysis was performed for 61 patients who received both NAs (blinatumomab and then InO [n = 40] or InO and then blinatumomab [n = 21]). The CR/CRi rate was 58% for patients who received InO as the second NA and 52% for patients who received blinatumomab as the second NA. The median OS was 10.5 for patients who received InO as the second NA and 5.9 months for patients who received blinatumomab as the second NA (P = .09). CONCLUSIONS: Although the limited power of this study to detect a significant difference between subgroups is acknowledged, the data suggest that blinatumomab and InO may have comparable efficacy as a first or second NA therapy in RR ALL.

Acute Lymphoblastic Leukemia, Version 2.2021, NCCN Clinical Practice Guidelines in Oncology.

The NCCN Guidelines for Acute Lymphoblastic Leukemia (ALL) focus on the classification of ALL subtypes based on immunophenotype and cytogenetic/molecular markers; risk assessment and stratification for risk-adapted therapy; treatment strategies for Philadelphia chromosome (Ph)-positive and Ph-negative ALL for both adolescent and young adult and adult patients; and supportive care considerations. Given the complexity of ALL treatment regimens and the required supportive care measures, the NCCN ALL Panel recommends that patients be treated at a specialized cancer center with expertise in the management of ALL This portion of the Guidelines focuses on the management of Ph-positive and Ph-negative ALL in adolescents and young adults, and management in relapsed settings.

Chromosomal instability upregulates interferon in acute myeloid leukemia.

Chromosome instability (CIN) generates genetic and karyotypic diversity that is common in hematological malignancies. Low to moderate levels of CIN are well tolerated and can promote cancer proliferation. However, high levels of CIN are lethal. Thus, CIN may serve both as a prognostic factor to predict clinical outcome and as a predictive biomarker. A retrospective study was performed to evaluate CIN in acute myeloid leukemia (AML). Chromosome mis-segregation frequency was correlated with clinical outcome in bone marrow core biopsy specimens from 17 AML cases. Additionally, we induced chromosome segregation errors in AML cell lines with AZ3146, an inhibitor of the Mps1 mitotic checkpoint kinase, to quantify the phenotypic effects of high CIN. We observed a broad distribution of chromosome mis-segregation frequency in AML bone marrow core specimens. High CIN correlated with complex karyotype in AML, as expected, although there was no clear survival effect. In addition to CIN, experimentally inducing chromosome segregation errors by Mps1 inhibition in AML cell lines causes DNA damage, micronuclei formation, and upregulation of interferon stimulated genes. High levels of CIN appear to be immunostimulatory, suggesting an opportunity to combine mitotic checkpoint inhibitors with immunotherapy in treatment of AML.

Guidelines Insights: Acute Lymphoblastic Leukemia, Version 1.2019.

Survival outcomes for older adults with acute lymphoblastic leukemia (ALL) are poor and optimal management is challenging due to higher-risk leukemia genetics, comorbidities, and lower tolerance to intensive therapy. A critical understanding of these factors guides the selection of frontline therapies and subsequent treatment strategies. In addition, there have been recent developments in minimal/measurable residual disease (MRD) testing and blinatumomab use in the context of MRD-positive disease after therapy. These NCCN Guidelines Insights discuss recent updates to the NCCN Guidelines for ALL regarding upfront therapy in older adults and MRD monitoring/testing in response to ALL treatment.

A closer look at blinatumomab.

On March 29, 2018, blinatumomab (Blincyto, Amgen) received an accelerated expanded approval for the treatment of adult and pediatric patients with B-cell precursor acute lymphoblastic leukemia (ALL) who are in first or second complete remission (CR) and have minimal residual disease (MRD). Blinatumomab was first approved for use in adult patients (in December 2014) and later in pediatric patients (in September 2016) with relapsed or refractory Philadelphia chromosome (Ph)-negative B-cell precursor ALL; the approval was expanded in July 2017 to include patients with Ph-positive disease. The agent is a bispecific CD19-directed CD3 T-cell engager.

NCCN Guidelines Insights: Acute Lymphoblastic Leukemia, Version 1.2017.

The prognosis for patients with newly diagnosed acute lymphoblastic leukemia (ALL) has improved with the use of more intensive chemotherapy regimens, tyrosine kinase inhibitors, targeted agents, and allogeneic hematopoietic cell transplantation. However, the management of relapsed or refractory (R/R) ALL remains challenging and prognosis is poor. The NCCN Guidelines for ALL provide recommendations on standard treatment approaches based on current evidence. These NCCN Guidelines Insights summarize treatment recommendations for R/R ALL and highlight important updates, and provide a summary of the panel's discussion and underlying data supporting the most recent recommendations for R/R ALL management.

A Survey of Baseline Tobacco Cessation Clinical Practices and Receptivity to Academic Detailing.

BACKGROUND: Thirty percent of all cancers are directly attributable to smoking, yet tobacco cessation treatment is not commonly provided at cancer clinics. OBJECTIVES: To assess current tobacco cessation practices among Wisconsin cancer clinics and to measure their receptivity to onsite training and technical assistance to increase their delivery of evidence-based tobacco cessation treatment. PROCESS: An online survey to assess current tobacco use identification and treatment clinical practice at 16 Wisconsin cancer clinics affiliated with the Wisconsin Oncology Network. OUTCOMES: Fifteen clinics responded to the survey and 11 agreed to onsite academic detailing. Most clinics reported that they identify tobacco users, but fewer advised smokers to quit or provided evidence-based tobacco cessation treatments. IMPLICATIONS: Less than half of Wisconsin cancer clinics consistently seize the oncology visit to address tobacco use, and the majority of cancer clinics are receptive to onsite academic detailing to increase the frequency and effectiveness of their tobacco cessation interventions.

New methods for assessing response in acute myeloid leukemia.

PURPOSE OF REVIEW: Patients with acute myeloid leukemia typically are monitored with bone marrow biopsy 7-10 days after completion of induction therapy. However, this test has relatively poor sensitivity and specificity for classifying patients likely to have long-term cure or even patients who will need additional therapy to achieve complete remission. Several new methods of assessing response are being studied and are summarized in this review. RECENT FINDINGS: Many new methods are being used to evaluate response assessment. Emerging data suggest that various types of clinical, chemical, and imaging biomarkers, as well as more sensitive techniques to measure minimal residual disease, can all help provide more accurate response assessment and prognostic information. SUMMARY: New techniques will improve the way we assess response to acute myeloid leukemia therapy. Larger confirmatory studies utilizing these novel markers of response to change treatment and to improve clinical outcomes are urgently needed.

A phase 2 study of weekly temsirolimus and bortezomib for relapsed or refractory B-cell non-Hodgkin lymphoma: A Wisconsin Oncology Network study.

BACKGROUND: Proteasome inhibitors and mammalian target of rapamycin inhibitors each have activity in various B-cell malignancies and affect distinct cellular pathways. Their combination has demonstrated synergy in vitro and in mouse models. METHODS: The authors conducted a single-arm, phase 2 trial of combined temsirolimus and bortezomib in patients with relapsed and refractory B-cell non-Hodgkin lymphoma (NHL) using a dosing scheme that was previously tested in multiple myeloma. The patients received bortezomib and temsirolimus weekly on days 1, 8, 15, and 22 of a 35-day cycle. RESULTS: Of 39 patients who received treatment, 3 achieved a complete response (7.7%; 95% confidence interval [CI], 1.6%-21%), and 9 had a partial response (PR) (23%; 95% CI, 11%-39%). Thus, the overall response rate (12 of 39 patients) was 31% (95% CI, 17%-48%), and the median progression-free survival was 4.7 months (95% CI, 2.1-7.8 months; 2 months for patients with diffuse large B-cell lymphoma [n = 18], 7.5 months for those with mantle cell lymphoma [n = 7], and 16.5 months for those with follicular lymphoma [n = 9]). Two extensively treated patients with diffuse large B-cell lymphoma achieved a complete response. There were no unexpected toxicities from the combination. CONCLUSIONS: The current results demonstrate that the combination of a mammalian target of rapamycin inhibitor and a proteasome inhibitor is safe and has activity in patients with heavily pretreated B-cell NHL. Further studies with this combination are warranted in specific subtypes of NHL.

A phase I and pharmacodynamic study of the histone deacetylase inhibitor belinostat plus azacitidine in advanced myeloid neoplasia.

Background We hypothesized that targeting two mechanisms of epigenetic silencing would be additive or synergistic with regard to expression of specific target genes. The primary objective of the study was to establish the maximum tolerated dose (MTD) of belinostat in combination with a fixed dose of azacitidine (AZA). Methods In Part A of the study, patients received a fixed dose of AZA, with escalating doses of belinostat given on the same days 1-5, in a 28 day cycle. Part B was designed to evaluate the relative contribution of belinostat to the combination based on analysis of pharmacodynamic markers, and incorporated a design in which patients were randomized during cycle 1 to AZA alone, or the combination, at the maximally tolerated dose of belinostat. Results 56 patients with myeloid neoplasia were enrolled. Dose escalation was feasible in part A, up to 1000 mg/m(2) dose level of belinostat. In Part B, 18 patients were assessable for quantitative analysis of specific target genes. At day 5 of therapy, MDR1 was significantly up-regulated in the belinostat/AZA arm compared with AZA alone arm (p = 0.0023). There were 18 responses among the 56 patients. Conclusions The combination of belinostat and AZA is feasible and associated with clinical activity. The recommended phase II dose is 1000 mg/m(2) of belinostat plus 75 mg/m(2) of AZA on days 1-5, every 28 days. Upregulation in MDR1 was observed in the combination arm at day 5 compared with the AZA alone arm, suggesting a relative biologic contribution of belinostat to the combination.

New strategies for the evaluation of the nadir bone marrow following induction in acute myeloid leukemia.

PURPOSE OF REVIEW: Patients with acute myeloid leukemia (AML) routinely undergo a bone marrow biopsy 7-10 days after induction chemotherapy to evaluate treatment effectiveness. Measuring blast count by morphology alone has been the standard hematopathologic technique. Although helpful to guide future treatment decisions, the early bone marrow does not predict well which patients will achieve complete remission, and ultimately be cured. New methods of assessing early treatment effectiveness are being developed. This review summarizes the current utility of early bone marrow evaluations and looks toward future developments. RECENT FINDINGS: More sensitive techniques than light microscopy are available to analyze the presence or absence of leukemia after treatment. These include flow-cytometry and polymerase chain reaction-based assays, and their use is playing a larger role in monitoring therapy effectiveness after induction and during consolidation. Importantly, novel techniques including enzymatic amplification staining (performed on bone marrow samples) and noninvasive molecular imaging have been studied and may play a role in future therapy asessment. SUMMARY: Identifying and implementing new tools to measure therapy effectiveness will be an important component of improving outcomes for patients with AML.

Safety and efficacy of fedratinib in patients with myelofibrosis previously treated with ruxolitinib: primary analysis of FREEDOM trial.

The phase 3b FREEDOM trial (ClinicalTrials.gov: NCT03755518) evaluates efficacy/safety of fedratinib in intermediate- or high-risk myelofibrosis patients with platelet count ≥50 × 109/L, previously treated with ruxolitinib. The trial design included protocol specified strategies to mitigate the risk for gastrointestinal (GI) adverse events (AEs), thiamine supplementation, and encephalopathy surveillance. Due to COVID-19, accrual was cut short with 38 patients enrolled. In the efficacy evaluable population (n = 35), nine (25.7%; 95% confidence interval 12.5-43.3) patients achieved primary endpoint of ≥35% spleen volume reduction (SVR) at end of cycle (EOC) 6; and 22 (62.9%) patients showed best overall response of ≥35% SVR up to end of treatment. Sixteen (44.4%) patients showed ≥50% reduction in total symptom score at EOC6 (n = 36). Compared to previously reported JAKARTA-2 trial, rates of GI AEs were lower, and no patient developed encephalopathy. Overall, FREEDOM study showed clinically relevant spleen and symptom responses with fedratinib, and effective mitigation of GI AEs.

Implementation of and Systems-Level Barriers to Guideline-Driven Germline Genetic Evaluation in the Care of Patients With Myelodysplastic Syndrome and Acute Myeloid Leukemia.

PURPOSE: Knowledge of an inherited predisposition to myelodysplastic syndrome (MDS) and AML has important clinical implications for treatment decisions, surveillance, and care of at-risk relatives. National Comprehensive Cancer Network (NCCN) guidelines recently incorporated recommendations for germline genetic evaluation of patients with MDS/AML on the basis of personal and family history features, but the practicality of implementing these recommendations has not been studied. METHODS: A hereditary hematology quality improvement (QI) committee was formed to implement these guidelines in a prospective cohort of patients diagnosed with MDS/AML. Referral for germline genetic testing was recommended for patients meeting NCCN guideline criteria. Referral patterns and genetic evaluation outcomes were compared with a historical cohort of patients with MDS/AML. Barriers to evaluation were identified. RESULTS: Of the 90 patients with MDS/AML evaluated by the QI committee, 59 (66%) met criteria for germline evaluation. Implementation of the QI committee led to more referrals for germline evaluation in accordance with NCCN guidelines (31% v 14%, P = .03). However, the majority of those meeting criteria were never referred due to high medical acuity or being deceased or in hospice at the time of QI committee recommendations. Despite this, two (17%) of the 12 patients undergoing genetic testing were diagnosed with a hereditary myeloid malignancy syndrome. CONCLUSION: Current NCCN guidelines resulted in two thirds of patients with MDS/AML meeting criteria for germline evaluation. A hereditary hematology-focused QI committee aided initial implementation and modestly improved NCCN guideline adherence. However, the high morbidity and mortality and prolonged inpatient stays associated with MDS/AML challenged traditional outpatient genetic counseling models. Further improvements in guideline adherence require innovating new models of genetic counseling and testing for this patient population.

Functionality of bone marrow mesenchymal stromal cells derived from head and neck cancer patients - A FDA-IND enabling study regarding MSC-based treatments for radiation-induced xerostomia.

PURPOSE: Salivary dysfunction is a significant side effect of radiation therapy for head and neck cancer (HNC). Preliminary data suggests that mesenchymal stromal cells (MSCs) can improve salivary function. Whether MSCs from HNC patients who have completed chemoradiation are functionally similar to those from healthy patients is unknown. We performed a pilot clinical study to determine whether bone marrow-derived MSCs [MSC(M)] from HNC patients could be used for the treatment of RT-induced salivary dysfunction. METHODS: An IRB-approved pilot clinical study was undertaken on HNC patients with xerostomia who had completed treatment two or more years prior. Patients underwent iliac crest bone marrow aspirate and MSC(M) were isolated and cultured. Culture-expanded MSC(M) were stimulated with IFNγ and cryopreserved prior to reanimation and profiling for functional markers by flow cytometry and ELISA. MSC(M) were additionally injected into mice with radiation-induced xerostomia and the changes in salivary gland histology and salivary production were examined. RESULTS: A total of six subjects were enrolled. MSC(M) from all subjects were culture expanded to > 20 million cells in a median of 15.5 days (range 8-20 days). Flow cytometry confirmed that cultured cells from HNC patients were MSC(M). Functional flow cytometry demonstrated that these IFNγ-stimulated MSC(M) acquired an immunosuppressive phenotype. IFNγ-stimulated MSC(M) from HNC patients were found to express GDNF, WNT1, and R-spondin 1 as well as pro-angiogenesis and immunomodulatory cytokines. In mice, IFNγ-stimulated MSC(M) injection after radiation decreased the loss of acinar cells, decreased the formation of fibrosis, and increased salivary production. CONCLUSIONS: MSC (M) from previously treated HNC patients can be expanded for auto-transplantation and are functionally active. Furthermore IFNγ-stimulated MSC(M) express proteins implicated in salivary gland regeneration. This study provides preliminary data supporting the feasibility of using autologous MSC(M) from HNC patients to treat RT-induced salivary dysfunction.

MLL fusion proteins preferentially regulate a subset of wild-type MLL target genes in the leukemic genome.

MLL encodes a histone methyltransferase that is critical in maintaining gene expression during embryonic development and hematopoiesis. 11q23 translocations result in the formation of chimeric MLL fusion proteins that act as potent drivers of acute leukemia. However, it remains unclear what portion of the leukemic genome is under the direct control of MLL fusions. By comparing patient-derived leukemic cell lines, we find that MLL fusion-bound genes are a small subset of that recognized by wild-type MLL. In an inducible MLL-ENL model, MLL fusion protein binding and changes in H3K79 methylation are limited to a specific portion of the genome, whereas wild-type MLL distributes to a much larger set of gene loci. Surprisingly, among 223 MLL-ENL-bound genes, only 12 demonstrate a significant increase in mRNA expression on induction of the fusion protein. In addition to Hoxa9 and Meis1, this includes Eya1 and Six1, which comprise a heterodimeric transcription factor important in several developmental pathways. We show that Eya1 has the capacity to immortalize hematopoietic progenitor cells in vitro and collaborates with Six1 in hematopoietic transformation assays. Altogether, our data suggest that MLL fusions contribute to the development of acute leukemia through direct activation of a small set of target genes.