Patient perspectives of 'Watch and Wait' for chronic haematological cancers: Findings from a qualitative study.

PURPOSE: Chronic blood cancers are incurable, and characterised by unpredictable, remitting-relapsing pathways. Management often involves periods of observation prior to treatment (if required), and post-treatment, in an approach known as 'Watch and Wait'. This study aimed to explore patient experiences of 'Watch and Wait'. METHODS: In-depth interviews with 35 patients (10 accompanied by relatives) with chronic lymphocytic leukaemia, follicular lymphoma, marginal zone lymphoma or myeloma. Data were analysed using descriptive qualitative techniques. RESULTS: Patient views of Watch and Wait ranged along a continuum, from immediate acceptance, to concern about treatment deferral. Significant ongoing anxiety and distress were described by some, due to the uncertain pathways associated with Watch and Wait. Infrequent contact with clinical staff was said to exacerbate this, as there was limited opportunity to ask questions and seek reassurance. Patients indicated that the impact of their malignancy could be underestimated by clinicians; possibly due to them comparing chronic and acute subtypes. Most patients lacked knowledge of blood cancers. Support from clinicians was considered greater among treated patients, possibly due to increased contact, and many drew on relatives for aid. Most patients were satisfied with their time-allocation with haematology staff, although experiences could be improved by greater access to clinical nurse specialists, counselling services, and community-based facilities. CONCLUSION: Experiences varied. Anxiety about unpredictable futures could be more distressing than any physical symptoms and have a greater impact on quality of life. Ongoing assessment could facilitate identification of difficulties, and is particularly important among individuals without supportive networks.

Genomic and microenvironmental landscape of stage I follicular lymphoma, compared with stage III/IV.

Although the genomic and immune microenvironmental landscape of follicular lymphoma (FL) has been extensively investigated, little is known about the potential biological differences between stage I and stage III/IV disease. Using next-generation sequencing and immunohistochemistry, 82 FL nodal stage I cases were analyzed and compared with 139 FL stage III/IV nodal cases. Many similarities in mutations, chromosomal copy number aberrations, and microenvironmental cell populations were detected. However, there were also significant differences in microenvironmental and genomic features. CD8+ T cells (P = .02) and STAT6 mutations (false discovery rate [FDR] <0.001) were more frequent in stage I FL. In contrast, programmed cell death protein 1-positive T cells, CD68+/CD163+ macrophages (P < .001), BCL2 translocation (BCL2trl+) (P < .0001), and KMT2D (FDR = 0.003) and CREBBP (FDR = 0.04) mutations were found more frequently in stage III/IV FL. Using clustering, we identified 3 clusters within stage I, and 2 clusters within stage III/IV. The BLC2trl+ stage I cluster was comparable to the BCL2trl+ cluster in stage III/IV. The two BCL2trl- stage I clusters were unique for stage I. One was enriched for CREBBP (95%) and STAT6 (64%) mutations, without BLC6 translocation (BCL6trl), whereas the BCL2trl- stage III/IV cluster contained BCL6trl (64%) with fewer CREBBP (45%) and STAT6 (9%) mutations. The other BCL2trl- stage I cluster was relatively heterogeneous with more copy number aberrations and linker histone mutations. This exploratory study shows that stage I FL is genetically heterogeneous with different underlying oncogenic pathways. Stage I FL BCL2trl- is likely STAT6 driven, whereas BCL2trl- stage III/IV appears to be more BCL6trl driven.

Incurable but treatable: Understanding, uncertainty and impact in chronic blood cancers-A qualitative study from the UK's Haematological Malignancy Research Network.

OBJECTIVE: Most blood cancers are incurable and typically follow unpredictable remitting-relapsing pathways associated with varying need for treatment, which may be distressing for patients. Our objective was to conduct a qualitative study to explore understanding among patients with such malignancies, including the explanations given by HCPs and the impact of uncertain trajectories, to generate evidence that could guide improvements in clinical practice. METHODS: The study is set within a population-based patient cohort (the Haematological Malignancy Research Network), in which care is delivered across 14 hospitals according to national guidelines. In-depth interviews were conducted with 35 patients with chronic lymphocytic leukaemia, follicular lymphoma, marginal zone lymphoma or myeloma; and 10 accompanying relatives. Purposive sampling ensured selection of information-rich participants and the data were interrogated using reflective thematic analysis. RESULTS: Rich data were collected and four themes (11 sub-themes) were identified: 1) Knowledge and understanding of chronic haematological malignancies; 2) Incurable but treatable; 3) Uncertainty about the future; and 4) Treatable (but still incurable): Impact on patients. Patients had rarely heard of blood cancer and many expressed difficulty understanding how an incurable malignancy that could not be removed, was treatable, often for long periods. While some were reassured that their cancer did not pose an immediate survival threat, others were particularly traumatised by the uncertain future it entailed, suffering ongoing emotional distress as a result, which could be more burdensome than any physical symptoms. Nonetheless, most interviewees understood that uncertain pathways were caused by the unpredictability of their disease trajectory, and not information being withheld. CONCLUSIONS: Many participants lacked knowledge about chronic haematological malignancies. HCPs acted to reassure patients about their diagnosis, and while this was appropriate and effective for some, it was less so for others, as the cancer-impact involved struggling to cope with ongoing uncertainty, distress and a shortened life-span.

BNIP3-dependent mitophagy promotes cytosolic localization of LC3B and metabolic homeostasis in the liver.

Mitophagy formed the basis of the original description of autophagy by Christian de Duve when he demonstrated that GCG (glucagon) induced macroautophagic/autophagic turnover of mitochondria in the liver. However, the molecular basis of liver-specific activation of mitophagy by GCG, or its significance for metabolic stress responses in the liver is not understood. Here we show that BNIP3 is required for GCG-induced mitophagy in the liver through interaction with processed LC3B; an interaction that is also necessary to localize LC3B out of the nucleus to cytosolic mitophagosomes in response to nutrient deprivation. Loss of BNIP3-dependent mitophagy caused excess mitochondria to accumulate in the liver, disrupting metabolic zonation within the liver parenchyma, with expansion of zone 1 metabolism at the expense of zone 3 metabolism. These results identify BNIP3 as a regulator of metabolic homeostasis in the liver through its effect on mitophagy and mitochondrial mass distribution.Abbreviations: ASS1, arginosuccinate synthetase; BNIP3, BCL2/adenovirus E1B interacting protein 3; CV, central vein; GCG - glucagon; GLUL, glutamate- ammonia ligase (glutamine synthetase); HCQ, hydroxychloroquine; LIR, LC3-interacting region; MAP1LC3B/LC3B, microtubule-associated protein 1 light chain 3 beta; mtDNA:nucDNA, ratio of mitochondrial DNA to nuclear DNA; PV, periportal vein; TOMM20, translocase of outer mitochondrial membrane protein 20.

Implications of TP53 allelic state for genome stability, clinical presentation and outcomes in myelodysplastic syndromes.

Tumor protein p53 (TP53) is the most frequently mutated gene in cancer1,2. In patients with myelodysplastic syndromes (MDS), TP53 mutations are associated with high-risk disease3,4, rapid transformation to acute myeloid leukemia (AML)5, resistance to conventional therapies6-8 and dismal outcomes9. Consistent with the tumor-suppressive role of TP53, patients harbor both mono- and biallelic mutations10. However, the biological and clinical implications of TP53 allelic state have not been fully investigated in MDS or any other cancer type. We analyzed 3,324 patients with MDS for TP53 mutations and allelic imbalances and delineated two subsets of patients with distinct phenotypes and outcomes. One-third of TP53-mutated patients had monoallelic mutations whereas two-thirds had multiple hits (multi-hit) consistent with biallelic targeting. Established associations with complex karyotype, few co-occurring mutations, high-risk presentation and poor outcomes were specific to multi-hit patients only. TP53 multi-hit state predicted risk of death and leukemic transformation independently of the Revised International Prognostic Scoring System (IPSS-R)11. Surprisingly, monoallelic patients did not differ from TP53 wild-type patients in outcomes and response to therapy. This study shows that consideration of TP53 allelic state is critical for diagnostic and prognostic precision in MDS as well as in future correlative studies of treatment response.

Targeted sequencing in DLBCL, molecular subtypes, and outcomes: a Haematological Malignancy Research Network report.

Based on the profile of genetic alterations occurring in tumor samples from selected diffuse large B-cell lymphoma (DLBCL) patients, 2 recent whole-exome sequencing studies proposed partially overlapping classification systems. Using clustering techniques applied to targeted sequencing data derived from a large unselected population-based patient cohort with full clinical follow-up (n = 928), we investigated whether molecular subtypes can be robustly identified using methods potentially applicable in routine clinical practice. DNA extracted from DLBCL tumors diagnosed in patients residing in a catchment population of ∼4 million (14 centers) were sequenced with a targeted 293-gene hematological-malignancy panel. Bernoulli mixture-model clustering was applied and the resulting subtypes analyzed in relation to their clinical characteristics and outcomes. Five molecular subtypes were resolved, termed MYD88, BCL2, SOCS1/SGK1, TET2/SGK1, and NOTCH2, along with an unclassified group. The subtypes characterized by genetic alterations of BCL2, NOTCH2, and MYD88 recapitulated recent studies showing good, intermediate, and poor prognosis, respectively. The SOCS1/SGK1 subtype showed biological overlap with primary mediastinal B-cell lymphoma and conferred excellent prognosis. Although not identified as a distinct cluster, NOTCH1 mutation was associated with poor prognosis. The impact of TP53 mutation varied with genomic subtypes, conferring no effect in the NOTCH2 subtype and poor prognosis in the MYD88 subtype. Our findings confirm the existence of molecular subtypes of DLBCL, providing evidence that genomic tests have prognostic significance in non-selected DLBCL patients. The identification of both good and poor risk subtypes in patients treated with R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone) clearly show the clinical value of the approach, confirming the need for a consensus classification.

Hodgkin lymphoma detection and survival: findings from the Haematological Malignancy Research Network.

BACKGROUND: Hodgkin lymphoma is usually detected in primary care with early signs and symptoms, and is highly treatable with standardised chemotherapy. However, late presentation is associated with poorer outcomes. AIM: To investigate the relationship between markers of advanced disease, emergency admission, and survival following a diagnosis of classical Hodgkin lymphoma (CHL). DESIGN & SETTING: The study was set within a sociodemographically representative UK population-based patient cohort of ~4 million, within which all patients were tracked through their care pathways, and linked to national data obtained from Hospital Episode Statistics (HES) and deaths. METHOD: All 971 patients with CHL newly diagnosed between 1 September 2004-31 August 2015 were followed until 18th December 2018. RESULTS: The median diagnostic age was 41.5 years (range 0-96 years), 55.2% of the patients were male, 31.2% had stage IV disease, 43.0% had a moderate-high or high risk prognostic score, and 18.7% were admitted via the emergency route prior to diagnosis. The relationship between age and emergency admission was U-shaped: more likely in patients aged <25 years and ≥70 years. Compared to patients admitted via other routes, those presenting as an emergency had more advanced disease and poorer 3-year survival (relative survival 68.4% [95% confidence interval {CI} = 60.3 to 75.2] versus 89.8% [95% CI = 87.0 to 92.0], respectively [P<0.01]). However, after adjusting for clinically important prognostic factors, no difference in survival remained. CONCLUSION: These findings suggest that CHL survival as a whole could be increased by around 4% if the cancer in patients who presented as an emergency had been detected at the same point as in other patients.

Blood transfusion history and risk of non-Hodgkin lymphoma: an InterLymph pooled analysis.

PURPOSE: To conduct a pooled analysis assessing the association of blood transfusion with risk of non-Hodgkin lymphoma (NHL). METHODS: We used harmonized data from 13 case-control studies (10,805 cases, 14,026 controls) in the InterLymph Consortium. Odds ratios (OR) and 95% confidence intervals (CI) were calculated using unconditional logistic regression, adjusted for study design variables. RESULTS: Among non-Hispanic whites (NHW), history of any transfusion was inversely associated with NHL risk for men (OR 0.74; 95% CI 0.65-0.83) but not women (OR 0.92; 95% CI 0.83-1.03), pheterogeneity = 0.014. Transfusion history was not associated with risk in other racial/ethnic groups. There was no trend with the number of transfusions, time since first transfusion, age at first transfusion, or decade of first transfusion, and further adjustment for socioeconomic status, body mass index, smoking, alcohol use, and HCV seropositivity did not alter the results. Associations for NHW men were stronger in hospital-based (OR 0.56; 95% CI 0.45-0.70) but still apparent in population-based (OR 0.84; 95% CI 0.72-0.98) studies. CONCLUSIONS: In the setting of a literature reporting mainly null and some positive associations, and the lack of a clear methodologic explanation for our inverse association restricted to NHW men, the current body of evidence suggests that there is no association of blood transfusion with risk of NHL.

Haematology nurses' perspectives of their patients' places of care and death: A UK qualitative interview study.

PURPOSE: Patients with haematological malignancies are more likely to die in hospital, and less likely to access palliative care than people with other cancers, though the reasons for this are not well understood. The purpose of our study was to explore haematology nurses' perspectives of their patients' places of care and death. METHOD: Qualitative description, based on thematic content analysis. Eight haematology nurses working in secondary and tertiary hospital settings were purposively selected and interviewed. Transcriptions were coded and analysed for themes using a mainly inductive, cross-comparative approach. RESULTS: Five inter-related factors were identified as contributing to the likelihood of patients' receiving end of life care/dying in hospital: the complex nature of haematological diseases and their treatment; close clinician-patient bonds; delays to end of life discussions; lack of integration between haematology and palliative care services; and barriers to death at home. CONCLUSIONS: Hospital death is often determined by the characteristics of the cancer and type of treatment. Prognostication is complex across subtypes and hospital death perceived as unavoidable, and sometimes the preferred option. Earlier, frank conversations that focus on realistic outcomes, closer integration of palliative care and haematology services, better communication across the secondary/primary care interface, and an increase in out-of-hours nursing support could improve end of life care and facilitate death at home or in hospice, when preferred.

Perspectives of bereaved relatives of patients with haematological malignancies concerning preferred place of care and death: A qualitative study.

BACKGROUND: People with haematological malignancies have different end-of-life care patterns from those with other cancers and are more likely to die in hospital. Little is known about patient and relative preferences at this time and whether these are achieved. AIM: To explore the experiences and reflections of bereaved relatives of patients with leukaemia, lymphoma or myeloma, and examine (1) preferred place of care and death; (2) perceptions of factors influencing attainment of preferences; and (3) changes that could promote achievement of preferences. DESIGN: Qualitative interview study incorporating 'Framework' analysis. SETTING/PARTICIPANTS: A total of 10 in-depth interviews with bereaved relatives. RESULTS: Although most people expressed a preference for home death, not all attained this. The influencing factors include disease characteristics (potential for sudden deterioration and death), the occurrence and timing of discussions (treatment cessation, prognosis, place of care/death), family networks (willingness/ability of relatives to provide care, knowledge about services, confidence to advocate) and resource availability (clinical care, hospice beds/policies). Preferences were described as changing over time and some family members retrospectively came to consider hospital as the 'right' place for the patient to have died. Others shared strong preferences with patients for home death and acted to ensure this was achieved. No patients died in a hospice, and relatives identified barriers to death in this setting. CONCLUSION: Preferences were not always achieved due to a series of complex, interrelated factors, some amenable to change and others less so. Death in hospital may be preferred and appropriate, or considered the best option in hindsight.

Disease-related factors affecting timely lymphoma diagnosis: a qualitative study exploring patient experiences.

BACKGROUND: Expediting cancer diagnosis is widely perceived as one way to improve patient outcomes. Evidence indicates that lymphoma diagnosis is often delayed, yet understanding of issues influencing this is incomplete. AIM: To explore patients' and their relatives' perceptions of disease-related factors affecting time to diagnosis of Hodgkin and non-Hodgkin lymphoma. DESIGN AND SETTING: Qualitative UK study involving patients with indolent and aggressive lymphomas, and their relatives, from an established population-based cohort in the north of England. METHOD: Semi-structured interviews with 35 patients and 15 of their relatives. Interviews were audiorecorded and transcribed, and qualitative descriptive analysis was undertaken. RESULTS: Participant accounts suggest that certain features of lymphoma can impact on patients' and healthcare providers' (HCPs) responses to disease onset. Three characteristics stand out: disease occurrence (rare), manifestation (varied), and investigative options (often inconclusive). Interviewees described how they, and some HCPs, lacked familiarity with lymphoma, seldom considering it a likely explanation for their symptoms. Symptoms reported were highly variable, frequently non-specific, and often initially thought to be associated with various benign, self-limiting causes. Blood tests and other investigations, while frequently able to detect abnormalities, did not reliably indicate malignancy. Interviewees reported the potential for improvements among HCPs in information gathering, communication of uncertainty, and re-presentation advice for non-resolving/progressive health changes. CONCLUSION: This study demonstrates the complex characteristics of lymphoma, perceived by patients as prolonging time to diagnosis, often despite significant effort by themselves, their relatives, and HCPs to expedite this process. The findings also illustrate why simple solutions to delayed diagnosis of lymphoma are lacking.

Autophagy, cancer stem cells and drug resistance.

Autophagy is a cellular survival mechanism that is induced by cancer therapy, among other stresses, and frequently contributes to cancer cell survival during long periods of dormancy and the eventual outgrowth of metastatic disease. Autophagy degrades large cellular structures that, once broken down, contribute to cellular survival through the recycling of their constituent metabolites. However, the extent to which this fuel function of autophagy is key to its role in promoting stemness, dormancy and drug resistance remains to be determined. Other roles for autophagy in determining cell fate more directly through targeted degradation of key transcription factors, such as p53 and FoxO3A, or by enforcing a reversible quiescent growth arrest, are discussed in this review. This review also highlights the need to parse out the roles of different forms of selective autophagy in stemness, CD44 expression and dormancy that, for example, are increasingly being attributed explicitly to mitophagy. The clinical relevance of this work and how an increased understanding of functions of autophagy in stemness, dormancy and drug resistance could be manipulated for increased therapeutic benefit, including eliminating minimal residual disease and preventing metastasis, are discussed. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Myeloma: Patient accounts of their pathways to diagnosis.

BACKGROUND: Pathways to myeloma diagnosis can be prolonged, and are often preceded by multiple GP consultations and emergency presentation. This is the first qualitative study to examine events leading to diagnosis by asking patients about their experiences during this time. METHODS: Set within a UK population-based cohort, semi-structured interviews were conducted with 20 myeloma patients with varying characteristics and pathways, 12 of whom invited their relatives to take part. Interviews were audio-recorded and qualitative analysis undertaken. RESULTS: Pre-diagnostic awareness of myeloma was minimal. Disease onset was typically described as gradual, and health changes vague but progressive, with increasing loss of function. A wide range of symptoms was reported, with the similarity of these to self-limiting conditions failing to raise suspicion of myeloma among patients and GPs. Patients tended to normalise symptoms at first, although all eventually sought GP advice. GPs often initially suggested benign diagnoses, which were sometimes only revised after multiple consultations with persistent/worsening symptoms. Referrals were made to various hospital specialities, and haematology if associated with abnormal blood tests suggestive of myeloma. Once in secondary care, progress towards diagnosis was generally rapid. CONCLUSIONS: Accounts confirmed that pathways to diagnosis could be difficult, largely due to the way myeloma presents, and how symptoms are interpreted and managed by patients and GPs. Recognition of 'normal' health and consultation patterns for the individual could promote appropriate help-seeking and timely referral when changes occur, and may be more effective than raising awareness about the myriad of potential symptoms associated with this disease.

Palliative care specialists' perceptions concerning referral of haematology patients to their services: findings from a qualitative study.

BACKGROUND: Haematological malignancies (leukaemias, lymphomas and myeloma) are complex cancers that are relatively common, affect all ages and have divergent outcomes. Although the symptom burden of these diseases is comparable to other cancers, patients do not access specialist palliative care (SPC) services as often as those with other cancers. To determine the reasons for this, we asked SPC practitioners about their perspectives regarding the barriers and facilitators influencing haematology patient referrals. METHODS: We conducted a qualitative study, set within the United Kingdom's (UK's) Haematological Malignancy Research Network (HMRN: www.hmrn.org ), a population-based cohort in the North of England. In-depth, semi-structured interviews were conducted with 20 SPC doctors and nurses working in hospital, community and hospice settings between 2012 and 2014. Interviews were digitally audio-recorded, transcribed and analysed for thematic content using the 'Framework' method. RESULTS: Study participants identified a range of barriers and facilitators influencing the referral of patients with haematological malignancies to SPC services. Barriers included: the characteristics and pathways of haematological malignancies; the close patient/haematology team relationship; lack of role clarity; late end of life discussions and SPC referrals; policy issues; and organisational issues. The main facilitators identified were: establishment of inter-disciplinary working patterns (co-working) and enhanced understanding of roles; timely discussions with patients and early SPC referral; access to information platforms able to support information sharing; and use of indicators to 'flag' patients' needs for SPC. Collaboration between haematology and SPC was perceived as beneficial and desirable, and was said to be increasing over time. CONCLUSIONS: This is the first UK study to explore SPC practitioners' perceptions concerning haematology patient referrals. Numerous factors were found to influence the likelihood of referral, some of which related to the organisation and delivery of SPC services, so were amenable to change, and others relating to the complex and unique characteristics and pathways of haematological cancers. Further research is needed to assess the extent to which palliative care is provided by haematology doctors and nurses and other generalists and ways in which clinical uncertainty could be used as a trigger, rather than a barrier, to referral.

Determinants of hospital death in haematological cancers: findings from a qualitative study.

OBJECTIVES: Current UK health policy promotes enabling people to die in a place they choose, which for most is home. Despite this, patients with haematological malignancies (leukaemias, lymphomas and myeloma) are more likely to die in hospital than those with other cancers, and this is often considered a reflection of poor quality end-of-life care. This study aimed to explore the experiences of clinicians and relatives to determine why hospital deaths predominate in these diseases. METHODS: The study was set within the Haematological Malignancy Research Network (HMRN-www.hmrn.org), an ongoing population-based cohort that provides infrastructure for evidence-based research. Qualitative interviews were conducted with clinical staff in haematology, palliative care and general practice (n=45) and relatives of deceased HMRN patients (n=10). Data were analysed for thematic content and coding and classification was inductive. Interpretation involved seeking meaning, salience and connections within the data. RESULTS: Five themes were identified relating to: the characteristics and trajectory of haematological cancers, a mismatch between the expectations and reality of home death, preference for hospital death, barriers to home/hospice death and suggested changes to practice to support non-hospital death, when preferred. CONCLUSIONS: Hospital deaths were largely determined by the characteristics of haematological malignancies, which included uncertain trajectories, indistinct transitions and difficulties predicting prognosis and identifying if or when to withdraw treatment. Advance planning (where possible) and better communication between primary and secondary care may facilitate non-hospital death.

Risk factors and time to symptomatic presentation in leukaemia, lymphoma and myeloma.

BACKGROUND: UK policy aims to improve cancer outcomes by promoting early diagnosis, which for many haematological malignancies is particularly challenging as the pathways leading to diagnosis can be difficult and prolonged. METHODS: A survey about symptoms was sent to patients in England with acute leukaemia, chronic lymphocytic leukaemia (CLL), chronic myeloid leukaemia (CML), myeloma and non-Hodgkin lymphoma (NHL). Symptoms and barriers to first help seeking were examined for each subtype, along with the relative risk of waiting >3 months' time from symptom onset to first presentation to a doctor, controlling for age, sex and deprivation. RESULTS: Of the 785 respondents, 654 (83.3%) reported symptoms; most commonly for NHL (95%) and least commonly for CLL (67.9%). Some symptoms were frequent across diseases while others were more disease-specific. Overall, 16% of patients (n=114) waited >3 months before presentation; most often in CML (24%) and least in acute leukaemia (9%). Significant risk factors for >3 months to presentation were: night sweats (particularly CLL and NHL), thirst, abdominal pain/discomfort, looking pale (particularly acute leukaemias), and extreme fatigue/tiredness (particularly CML and NHL); and not realising symptom(s) were serious. CONCLUSIONS: These findings demonstrate important differences by subtype, which should be considered in strategies promoting early presentation. Not realising the seriousness of some symptoms indicates a worrying lack of public awareness.

Multiplexed metagenome mining using short DNA sequence tags facilitates targeted discovery of epoxyketone proteasome inhibitors.

In molecular evolutionary analyses, short DNA sequences are used to infer phylogenetic relationships among species. Here we apply this principle to the study of bacterial biosynthesis, enabling the targeted isolation of previously unidentified natural products directly from complex metagenomes. Our approach uses short natural product sequence tags derived from conserved biosynthetic motifs to profile biosynthetic diversity in the environment and then guide the recovery of gene clusters from metagenomic libraries. The methodology is conceptually simple, requires only a small investment in sequencing, and is not computationally demanding. To demonstrate the power of this approach to natural product discovery we conducted a computational search for epoxyketone proteasome inhibitors within 185 globally distributed soil metagenomes. This led to the identification of 99 unique epoxyketone sequence tags, falling into 6 phylogenetically distinct clades. Complete gene clusters associated with nine unique tags were recovered from four saturating soil metagenomic libraries. Using heterologous expression methodologies, seven potent epoxyketone proteasome inhibitors (clarepoxcins A-E and landepoxcins A and B) were produced from these pathways, including compounds with different warhead structures and a naturally occurring halohydrin prodrug. This study provides a template for the targeted expansion of bacterially derived natural products using the global metagenome.