Obesity in adult acute myeloid leukemia is not associated with inferior response or survival even when dose capping anthracyclines: An ECOG-ACRIN analysis.

BACKGROUND: Obesity (body mass index [BMI] ≥30 kg/m2 ) is an important epidemiological risk factor for developing acute myeloid leukemia (AML). Therefore, the authors studied the association of obesity with clinical and genetic phenotype and its impact on outcome in adults with AML. METHODS: The authors analyzed BMI in 1088 adults who were receiving intensive remission induction and consolidation therapy in two prospective, randomized therapeutic clinical trials of the Eastern Cooperative Oncology Group-American College of Radiology Imaging Network: E1900 (ClinicalTrials.gov identifier NCT00049517; patients younger than 60 years) and E3999 (ClinicalTrials.gov identifier NCT00046930; patients aged 60 years or older). RESULTS: Obesity was prevalent at diagnosis (33%) and, compared with nonobesity, was associated with intermediate-risk cytogenetics group (p = .008), poorer performance status (p = .01), and a trend toward older age (p = .06). Obesity was not associated with somatic mutations among a selected 18-gene panel that was tested in a subset of younger patients. Obesity was not associated with clinical outcome (including complete remission, early death, or overall survival), and the authors did not identify any patient subgroup that had inferior outcomes based on BMI. Obese patients were significantly more likely to receive <90% of the intended daunorubicin dose despite protocol specification, particularly in the E1900 high-dose (90 mg/m2 ) daunorubicin arm (p = .002); however, this did not correlate with inferior overall survival on multivariate analysis (hazard ratio, 1.39; 95% confidence interval, 0.90-2.13; p = .14). CONCLUSIONS: Obesity is associated with unique clinical and disease-related phenotypic features in AML and may influence physician treatment decisions regarding daunorubicin dosing. However, the current study demonstrates that obesity is not a factor in survival, and strict adherence to body surface area-based dosing is not necessary because dose adjustments do not affect outcomes.

Prognostic effect of gender on outcome of treatment for adults with acute myeloid leukaemia.

There are conflicting reports in the literature suggesting that one gender or the other has a better survival with acute myeloid leukaemia (AML). The present study was done in an attempt to resolve the issue. The effect of gender was examined on 3546 newly diagnosed patients with AML, including 548 patients with acute promyelocytic leukaemia (APL) enrolled in 10 multi-institutional treatment studies from March 1984 to November 2008. Kaplan-Meier estimates were used to estimate event-time distributions for survival and multivariate models were used to examine the gender effect after adjusting for multiple risk factors. P values were based on two-sided tests. Non-APL female patients had a significantly better overall (OS) but not disease-free survival (DFS) than males, irrespective of age, initial white blood cell count, or dose of daunorubicin. No differences were observed for obese or FMS-like tyrosine kinase 3-internal tandem duplication (FLT3-ITD)-positive patients. Female patients with APL had a significantly better OS and DFS than male patients with APL, and differences in survival were greater for patients with t(15;17) + other cytogenetic abnormalities compared with those with t(15;17) only. Gender is an independent prognostic variable in patients with AML. Whether these survival differences are due to hormonal, genetic or pharmacokinetic differences between the sexes or differential toxin exposure such as smoking is unknown. However, the former seems less likely as patient age did not influence the survival advantage for female patients.

Very poor long-term survival in past and more recent studies for relapsed AML patients: The ECOG-ACRIN experience.

This study examines the long-term OS of relapsed AML patients who were enrolled to 9 successive ECOG-ACRIN trials for newly diagnosed AML, during 1984-2008. The objectives were to examine whether there is a trend of improvement in the survival of relapsed AML patients in the more recent studies and to search for prognostic factors that are associated with long-term OS after relapse. A total of 3012 patients were enrolled, 1779 (59.1%) achieved CR1 and of these, 58.9% relapsed. The median follow-up was 9.7 years. The median OS from relapse was 0.5 years and the 5-year OS was 10 (±1)%. These results were similar even for the most recent studies. A multivariate model showed that age, cytogenetics at diagnosis, duration of CR1 and undergoing allogeneic transplantation were significantly associated with OS from relapse. Even among patients who relapsed with better prognostic factors; age < 40 and CR1 > 12 months, there was no significant OS difference between the studies. In conclusion, this large cohort appears to confirm that the survival of AML patients postrelapse continues to be dismal and has not improved during the past quarter of a century.

Predicting symptoms of anxiety and depression in patients living with advanced cancer: the differential roles of hope and optimism.

PURPOSE: Psychological distress is related to poorer functioning and reduced quality of life in patients with advanced cancer and may have untoward influences on treatment decisions. Current research on factors associated with this distress is limited, making targeted interventions to reduce it suboptimal. We examined the relationships between two goal-related expectancies and two of the most common symptoms of psychological distress in patients living with advanced cancer: anxiety and depressive symptoms. METHODS: Patients with advanced gastrointestinal cancer, colorectal cancer, lung cancer, or melanoma (N = 84) completed measures of anxiety, depressive symptoms, optimism, hope, and prediction for 12-month survival. Oncologists provided prediction for patient 12-month survival and patient performance status. RESULTS: Hope, but not optimism, was associated with less severe depressive symptoms (ß = - 0.42). Conversely, optimism, but not hope, was associated with less severe anxiety symptoms (ß = - 0.36). CONCLUSIONS: Hope and optimism appear to be associated with different aspects of psychological distress in patients living with advanced cancer. This may be explained by different appraisals of the uncertainty and distress that are associated with living with advanced-stage cancer. Hope- or optimism-focused interventions can be tailored to help alleviate specific aspects of psychological distress among these patients.

Life and treatment goals of patients with advanced, incurable cancer.

PURPOSE: Goals of care conversations have been suggested as a strategy for helping patients with advanced cancer manage the uncertainty and distress associated with end-of-life care. However, knowledge deficits about patient goals limit the utility of such conversations. We described the life and treatment goals of patients with incurable cancers, including goal values and expectancies. We examined the associations between paramount goals and patient prognosis, performance status, and psychological adjustment. METHODS: Patients with advanced lung cancer, gastrointestinal cancer, or melanoma (N = 84) completed measures of prognosis for 12-month survival, hope, optimism, depression, and anxiety. Oncologists provided patient performance status and prognosis for 12-month survival. We conducted interviews with a subset of patients (N = 63), eliciting life and treatment goals, values, and expectancies. RESULTS: Patient life goals resembled goals among healthy populations; whereas, treatment goals were perceived as separate and more important. Cure and fight cancer emerged as the most important goals. Patients who valued cure the most had worse performance status (M = 1.46 vs. 0.78) and more depressive symptoms (M = 6.30 vs. 3.50). Patients who valued fight cancer the most had worse self-prognosis (M = 69.23 % vs. 86.11 %), fewer treatment goals (M = 2.08 vs. 3.16), and lower optimism (M = 15.00 vs. 18.32). CONCLUSIONS: Patients with advanced cancer perceive treatment goals as separate from and more important than life goals. They hold optimistic expectancies for achieving their goals and for survival. Valuing cure highly may put patients at risk for experiencing psychological maladjustment.

REVEAL-1, a phase 2 dose regimen optimization study of vosaroxin in older poor-risk patients with previously untreated acute myeloid leukaemia.

This phase 2 study (N = 116) evaluated single-agent vosaroxin, a first-in-class anticancer quinolone derivative, in patients ≥60 years of age with previously untreated unfavourable prognosis acute myeloid leukaemia. Dose regimen optimization was explored in sequential cohorts (A: 72 mg/m(2)  d 1, 8, 15; B: 72 mg/m(2)  d 1, 8; C: 72 mg/m(2) or 90 mg/m(2)  d 1, 4). The primary endpoint was combined complete remission rate (complete remission [CR] plus CR with incomplete platelet recovery [CRp]). Common (>20%) grade ≥3 adverse events were thrombocytopenia, febrile neutropenia, anaemia, neutropenia, sepsis, pneumonia, stomatitis and hypokalaemia. Overall CR and CR/CRp rates were 29% and 32%; median overall survival (OS) was 7·0 months; 1-year OS was 34%. Schedule C (72 mg/m(2) ) had the most favourable safety and efficacy profile, with faster haematological recovery (median 27 d) and lowest incidence of aggregate sepsis (24%) and 30-d (7%) and 60-d (17%) all-cause mortality; at this dose and schedule, CR and CR/CRp rates were 31% and 35%, median OS was 7·7 months and 1-year OS was 38%. Overall, vosaroxin resulted in low early mortality and an encouraging response rate; vosaroxin 72 mg/m(2)  d 1, 4 is recommended for further study in this population. Registered at www.clinicaltrials.gov: #NCT00607997.

A phase 1b/2 study of vosaroxin in combination with cytarabine in patients with relapsed or refractory acute myeloid leukemia.

Vosaroxin is a first-in-class anticancer quinolone derivative that intercalates DNA and inhibits topoisomerase II. This study assessed the safety and tolerability of vosaroxin plus cytarabine in patients with relapsed/refractory acute myeloid leukemia. Escalating vosaroxin doses (10-minute infusion; 10-90 mg/m(2); days 1, 4) were given in combination with cytarabine on one of two schedules: schedule A (24-hour continuous intravenous infusion, 400 mg/m(2)/day, days 1-5) or schedule B (2-hour intravenous infusion, 1 g/m(2)/day, days 1-5). Following dose escalation, enrollment was expanded at the maximum tolerated dose. Of 110 patients enrolled, 108 received treatment. The maximum tolerated dose of vosaroxin was 80 mg/m(2) for schedule A (dose-limiting toxicities: grade 3 bowel obstruction and stomatitis) and was not reached for schedule B (recommended phase 2 dose: 90 mg/m(2)). In the efficacy population (all patients in first relapse or with primary refractory disease treated with vosaroxin 80-90 mg/m(2); n=69), the complete remission rate was 25% and the complete remission/complete remission with incomplete blood count recovery rate was 28%. The 30-day all-cause mortality rate was 2.5% among all patients treated at a dose of 80-90 mg/m(2). Based upon these results, a phase 3 trial of vosaroxin plus cytarabine was initiated in patients with relapsed/refractory acute myeloid leukemia. (Clinicaltrials.gov identifier: NCT00541866).

Cyclophosphamide/fludarabine nonmyeloablative allotransplant for acute myeloid leukemia.

We compared survival outcomes following myeloablative allotransplant (MAT) or cyclophosphamide/fludarabine (Cy/Flu) nonmyeloablative allotransplant (NMAT) for 165 patients with acute myelogenous leukemia (AML) in remission or without frank relapse. Patients who received NMAT were more likely to be older and have secondary AML and lower performance status. At a median follow-up of 61 months, median event-free survival and overall survival survival were not different between NMAT and MAT in univariate as well as multivariate analyses. Cy/Flu NMAT may provide similar disease control and survival when compared with MAT in patients with AML in remission or without frank relapse.

Results from a randomized trial of salvage chemotherapy followed by lestaurtinib for patients with FLT3 mutant AML in first relapse.

In a randomized trial of therapy for FMS-like tyrosine kinase-3 (FLT3) mutant acute myeloid leukemia in first relapse, 224 patients received chemotherapy alone or followed by 80 mg of the FLT3 inhibitor lestaurtinib twice daily. Endpoints included complete remission or complete remission with incomplete platelet recovery (CR/CRp), overall survival, safety, and tolerability. Correlative studies included pharmacokinetics and analysis of in vivo FLT3 inhibition. There were 29 patients with CR/CRp in the lestaurtinib arm and 23 in the control arm (26% vs 21%; P = .35), and no difference in overall survival between the 2 arms. There was evidence of toxicity in the lestaurtinib-treated patients, particularly those with plasma levels in excess of 20 µM. In the lestaurtinib arm, FLT3 inhibition was highly correlated with remission rate, but target inhibition on day 15 was achieved in only 58% of patients receiving lestaurtinib. Given that such a small proportion of patients on this trial achieved sustained FLT3 inhibition in vivo, any conclusions regarding the efficacy of combining FLT3 inhibition with chemotherapy are limited. Overall, lestaurtinib treatment after chemotherapy did not increase response rates or prolong survival of patients with FLT3 mutant acute myeloid leukemia in first relapse. This study is registered at www.clinicaltrials.gov as #NCT00079482.

We were in the fight together: The expectations of bereaved caregivers of patients with acute myeloid leukemia from diagnosis to death.

PURPOSE: Patients with hematologic malignancies are more optimistic than their oncologists and their expectations may be a barrier to timely hospice care. Patient expectations toward the end of life (EOL), however, have not been characterized. In this study, we analyzed interviews of bereaved caregivers to understand the expectations of patients diagnosed with acute myeloid leukemia and the factors that influenced those expectations, from diagnosis until death. METHODS: Bereaved caregivers (n = 19) participated in an in-depth interview that included open-ended and semi-structured prompts, within 18 months following patient death. Interviews were analyzed using a modified grounded theory qualitative approach and constant comparative methods. RESULTS: We identified three themes relevant to expectations: Taking Stock, Being Stuck, and Disruption. Caregivers described clear and optimistic early expectations that AML is treatable. It was understood that treatment was required to survive. Later, when treatment options were limited, patients and caregivers became stuck in a belief that the patient could continue to live indefinitely on supportive care or at least until new more effective treatments were available. Caregivers often realized that the patient was at the end of life only when faced with a disruption, an event or conversation that changed their expectations for indefinite patient survival. CONCLUSIONS: Caregivers described continued expectations for patient survival until presented with irrefutable evidence to the contrary. The study suggests patients and caregivers may make better EOL care decisions if their early optimism is deliberately moderated by ongoing conversations with clinicians that highlight the sentinel events that signal treatment failure and explain how expectations and goals are changing from living a longer life to dying a more comfortable death.

Lenalidomide and prednisone for myelofibrosis: Eastern Cooperative Oncology Group (ECOG) phase 2 trial E4903.

A multicenter Eastern Cooperative Group (ECOG) phase 2 trial assessed whether adding prednisone to lenalidomide would improve previously reported responses in persons with myelofibrosis (MF). Forty-eight subjects with anemia (42 evaluable) received lenalidomide, 10 mg/d, with a 3-month low-dose prednisone taper. Ten subjects received 3 months, and 25 received 6 months of therapy. Myelosuppression was the main toxicity with 88% with ≥ grade 3 hematologic toxicity and 45% ≥ grade 3 nonhematologic toxicity. There were responses in 10 subjects (23%) using the International Working Group for Myelofibrosis Research and Treatment (IWG-MRT)-defined clinical improvement of anemia in 8 (19%) and/or decreased spleen size in 4 (10%). Serial bone marrow analysis showed no resolution of disease-related fibrosis or angiogenesis. With a median follow-up of 2.3 years, 23 subjects are alive. Lenali-domide and prednisone for myelofibro-sis evaluated through a multicentered-cooperative group mechanism is only modestly active and myelosuppre-sive. This study was registered at http://clinicaltrials.gov as NCT00227591.

Zosuquidar, a novel modulator of P-glycoprotein, does not improve the outcome of older patients with newly diagnosed acute myeloid leukemia: a randomized, placebo-controlled trial of the Eastern Cooperative Oncology Group 3999.

Zosuquidar, which modulates P-glycoprotein (P-gp) with minimal delay of anthracycline clearance, may reverse P-gp-mediated resistance in acute myeloid leukemia without increased toxicity. A total of 449 adults older than 60 years with acute myeloid leukemia or high-risk myelodysplastic syndrome enrolled in a randomized placebo-controlled double-blind trial (Eastern Cooperative Oncology Group 3999). Overall survival was compared between patients receiving conventional-dose cytarabine and daunorubicin and either zosuquidar (550 mg; 212 patients) or placebo (221 patients). Median and 2-year overall survival values were 7.2 months and 20% on zosuquidar and 9.4 months and 23% on placebo, respectively (P = .281). Remission rate was 51.9% on zosuquidar and 48.9% on placebo. All cause mortality to day 42 was not different (zosuquidar 22.2% vs placebo 16.3%; P = .158). In vitro modulation of P-gp activity by zosuquidar and expression of P-gp, multidrug resistance-related protein 1, lung resistance protein, and breast cancer resistance protein, were comparable in the 2 arms. Poor-risk cytogenetics were more common in P-gp(+) patients. P-gp expression and cytogenetics were correlated, though independent prognostic factors. We conclude that zosuquidar did not improve outcome in older acute myeloid leukemia, in part, because of the presence P-gp independent mechanisms of resistance. This trial is registered at www.clinicaltrials.gov as #NCT00046930.

Inhibition of Syk with fostamatinib disodium has significant clinical activity in non-Hodgkin lymphoma and chronic lymphocytic leukemia.

Certain malignant B cells rely on B-cell receptor (BCR)-mediated survival signals. Spleen tyrosine kinase (Syk) initiates and amplifies the BCR signal. In in vivo analyses of B-cell lymphoma cell lines and primary tumors, Syk inhibition induces apoptosis. These data prompted a phase 1/2 clinical trial of fostamatinib disodium, the first clinically available oral Syk inhibitor, in patients with recurrent B-cell non-Hodgkin lymphoma (B-NHL). Dose-limiting toxicity in the phase 1 portion was neutropenia, diarrhea, and thrombocytopenia, and 200 mg twice daily was chosen for phase 2 testing. Sixty-eight patients with recurrent B-NHL were then enrolled in 3 cohorts: (1) diffuse large B-cell lymphoma (DLBCL), (2) follicular lymphoma (FL), and (3) other NHL, including mantle cell lymphoma (MCL), marginal zone lymphoma (MZL), mucosa-associated lymphoid tissue lymphoma, lymphoplasmacytic lymphomas, and small lymphocytic leukemia/chronic lymphocytic leukemia (SLL/CLL). Common toxicities included diarrhea, fatigue, cytopenias, hypertension, and nausea. Objective response rates were 22% (5 of 23) for DLBCL, 10% (2 of 21) for FL, 55% (6 of 11) for SLL/CLL, and 11% (1/9) for MCL. Median progression-free survival was 4.2 months. Disrupting BCR-induced signaling by inhibiting Syk represents a novel and active therapeutic approach for NHL and SLL/CLL. This trial was registered at www.clinicaltrials.gov as #NCT00446095.

Illness appraisal, religious coping, and psychological responses in men with advanced cancer.

PURPOSE: Patients experience diverse psychological responses to cancer. Appraisals and coping have been shown to predict psychological responses to stressors. For men with advanced cancer, appraisal of cancer's impact on their lives (illness appraisal) and religious coping may be particularly important predictors of psychological responses. We examined the relationships among illness appraisal, religious coping, and positive and negative psychological responses while controlling for disease and patient characteristics. METHOD: Eighty-six men with advanced cancer completed measures, including constructed Meaning of Illness Scale, Brief Religious Coping Scale, Hospital Anxiety and Depression Scale, mini-Mental Adjustment to Cancer Scale, and Posttraumatic Growth Inventory. Treating oncologists completed questions about disease status and estimated the chances of the patient surviving 6 months. RESULTS: Psychological distress was predicted by prognosis (ß = -0.20), illness appraisal (ß = -0.48), and negative religious coping (ß = 0.24). Negative mental adjustment was predicted by prognosis (ß = -0.23) and illness appraisal (ß = -0.57). Positive mental adjustment was predicted by illness appraisal (ß = 0.46) and positive religious coping (ß = 0.29). Posttraumatic growth was predicted by positive religious coping (ß = 0.49). CONCLUSIONS: Illness appraisal was more consistently associated with psychological responses to advanced cancer than patient or disease characteristics. Consequently, helping patients with their illness appraisals may be effective for improving patient psychological well-being.

Goals of care communication and higher-value care for patients with advanced-stage cancer: A systematic review of the evidence.

CONTEXT: Goals-of-care communication (GOCC) is recommended to increase the value of cancer care near the end of life (EOL). OBJECTIVES: Conduct a systematic review of the evidence that GOCC is associated with higher-value care. METHODS: We searched PubMed, Scopus, Ovid MEDLINE, EMBASE, EMB Reviews, CINAHL, and PsycInfo from inception to July 2019. We analyzed the population,design, and results and the authors' definitions of GOCC. Risk of bias was assessed. RESULTS: Thirty-two articles were selected. Ten articles reported results from 8 interventions; 17 characterized participants' perspectives; and 5 were retrospective The topics, behaviors, timing, and anticipated outcomes of GOCC varied significantly and were indistinguishable from practices such as advance care planning. GOCC typically focused on treatment outcomes rather than patients' goals. Four of 5 interventions increased evidence of GOCC after clinician training. Only one reported improved patient outcomes. CONCLUSION: No consensus exists about what GOCC entails. There is limited evidence that GOCC increases the value of EOL care. PRACTICE IMPLICATIONS: Future studies should focus on how to engage patients in conversations about their personal goals and integrate their goals into care planning. Clinicians can encourage GOCC by explaining how patients' goals influence decisions especially as treatment options become limited.

Bereaved Informal Caregivers Rarely Recall a Relationship Between Transfusions and Hospice in Acute Myeloid Leukemia.

AIMS: The inability to prescribe blood transfusions is a potential barrier to timely hospice enrollment for patients with blood cancers. The benefits and harms of transfusions near the end of life (EOL), however, are poorly characterized and patients' preferences are unknown. We sought to characterize the recollections of bereaved caregivers about the relationships between transfusions and hospice enrollment decisions. METHODS: We recruited 18 bereaved caregivers of 15 decedents who died within 6-18 months of the interview. Interviews focused on caregivers' recollections of transfusion and hospice enrollment decisions. Transcripts were analyzed for themes. RESULTS: We identified 2 themes. First, caregivers described that transfusions were necessary and the decisions to receive transfusions or not were deferred to the clinicians. Second, only 1 caregiver recalled transfusions as relevant to hospice decisions. In that instance there was a delay. Caregivers identified difficulties recognizing death was imminent, hope for miracles, and the necessity of accepting life was ending as more relevant barriers. CONCLUSIONS: The results indicate clinicians' beliefs in transfusion at EOL may be a more relevant barrier to hospice enrollment than patients' preferences. Strategies to evaluate accurately and discuss the actual benefits and harms of transfusions at the EOL are necessary to advise patients and integrate their preferences into decisions.

CNS involvement in AML at diagnosis is rare and does not affect response or survival: data from 11 ECOG-ACRIN trials.

Central nervous system (CNS) involvement in patients with newly diagnosed acute myeloid leukemia (AML) is rare, and systematic data regarding outcome are scarce. This retrospective study summarized data from 11 consecutive Eastern Cooperative Oncology Group-American College of Radiology Imaging Network (ECOG-ACRIN) clinical trials for patients with newly diagnosed AML. In all, 3240 patients with AML were analyzed, and 36 (1.11%) were found to have CNS involvement at diagnosis. The incidence of CNS disease among the 5 studies with per protocol mandatory lumbar puncture (LP) was similar to the incidence among studies in which LP was performed at the discretion of the investigator (0.86% vs 1.41%; P = .18). There was no significant difference in the rate of complete remission (CR) among patients with CNS involvement and those with other extramedullary disease (EMD) sites or those with no EMD (52.8% vs 59.3%-60%). The median overall survival (OS) for patients who were CNS positive, who had other EMD, or who had no EMD was 11.4, 11.3, and 12.7 months, respectively. There was no difference in OS among patients with CNS involvement, those with other EMD (hazard ratio [HR], 0.96; adjusted P = .84), and those with no EMD (HR, 1.19; adjusted P = .44). In conclusion, the reported incidence of CNS involvement in patients with newly diagnosed AML is low (1.1%), irrespective of whether an LP is mandatory or not. The presence of CNS disease at diagnosis in and of itself does not seem to portend a poor prognosis for achieving an initial CR or for OS.

Failure of three novel regimens to improve outcome for patients with relapsed or refractory acute myeloid leukaemia: a report from the Eastern Cooperative Oncology Group.

The treatment of relapsed acute myeloid leukaemia (AML) remains unsatisfactory. We conducted a phase II randomized trial where patients received intermediate-dose cytarabine for 4 d followed by gemtuzumab ozogamicin on day 5 (Arm A), or combined with liposomal daunorubicin for 3 d (Arm B), or cytarabine given for 5 d combined with cyclophosphamide for 3 d and topotecan by continuous infusion for 5 d (Arm C). Eligible patients had primary refractory AML, a first relapse after a remission of <1 year, or a second or greater relapse. The primary objective of this trial was attainment of a conventional complete remission (CR) or a CR without platelet recovery (CRp) in at least 40% of patients. The CR/CRp rates for the 82 eligible patients were 3/26 (12%) in Arm A, 2/29 (7%) in Arm B, and 1/27 (4%) in Arm C. No patients who had relapsed within 6 months of initial CR or who had suffered multiple relapses responded. More than 95% of patients subsequently died of AML. No unexpected toxicities were encountered. We conclude that none of these three regimens were effective enough in the treatment of high-risk relapsed or refractory AML to warrant further study. This trial was registered at http://www.clinicaltrials.gov as #NCT00005962.

Targeted detection and quantitation of histone modifications from 1,000 cells.

Histone post-translational modifications (PTMs) create a powerful regulatory mechanism for maintaining chromosomal integrity in cells. Histone acetylation and methylation, the most widely studied histone PTMs, act in concert with chromatin-associated proteins to control access to genetic information during transcription. Alterations in cellular histone PTMs have been linked to disease states and have crucial biomarker and therapeutic potential. Traditional bottom-up mass spectrometry of histones requires large numbers of cells, typically one million or more. However, for some cell subtype-specific studies, it is difficult or impossible to obtain such large numbers of cells and quantification of rare histone PTMs is often unachievable. An established targeted LC-MS/MS method was used to quantify the abundance of histone PTMs from cell lines and primary human specimens. Sample preparation was modified by omitting nuclear isolation and reducing the rounds of histone derivatization to improve detection of histone peptides down to 1,000 cells. In the current study, we developed and validated a quantitative LC-MS/MS approach tailored for a targeted histone assay of 75 histone peptides with as few as 10,000 cells. Furthermore, we were able to detect and quantify 61 histone peptides from just 1,000 primary human stem cells. Detection of 37 histone peptides was possible from 1,000 acute myeloid leukemia patient cells. We anticipate that this revised method can be used in many applications where achieving large cell numbers is challenging, including rare human cell populations.