Secondary malignancies after allogeneic stem-cell transplantation in the era of reduced-intensity conditioning; the incidence is not reduced

[Secondary cancers following allogeneic hematopoietic stem cell transplantation: Guidelines from the Francophone Society of Bone Marrow Transplantation and Cellular Therapy (SFGM-TC)]

The Francophone Society of Bone Marrow Transplantation and Cellular Therapy (SFGM-TC) held the 13th edition of the Clinical Practices Harmonization Workshops. Our workgroup reviewed the current data on the incidence, screening methods and international guidelines for the prevention of secondary solid cancers following allogeneic hematopoietic stem cell transplantation. The purpose of this workshop was to provide recommendations for the screening and prevention of secondary malignancies to Francophone transplantation centers.

Oral microbial changes and oral disease management before and after the treatment of hematological malignancies: a narrative review

OBJECTIVES

Patients with hematological malignancies have dynamic changes in oral microbial communities before and after treatment. This narrative review describes the changes in oral microbial composition and diversity, and discusses an oral microbe-oriented strategy for oral disease management.

MATERIALS AND METHODS

A literature search was performed in PubMed/Medline, Web of Science, and Embase for articles published between 1980 and 2022. Any articles on the changes in oral microbial communities in patients with hematological malignancies and their effects on disease progression and prognosis were included.

RESULTS

Oral sample detection and oral microbial sequencing analysis of patients with hematological malignancies showed a correlation between changes in oral microbial composition and diversity and disease progression and prognosis. The possible pathogenic mechanism of oral microbial disorders is the impairment of mucosal barrier function and microbial translocation. Probiotic strategies, antibiotic strategies, and professional oral care strategies targeting the oral microbiota can effectively reduce the risk of oral complications and the grade of severity in patients with hematological malignancies.

CLINICAL RELEVANCE

This review provides dentists and hematologists with a comprehensive understanding of the host-microbe associated with hematologic malignancies and oral disease management advice.

Molecular disparity of HLA-DPB1 is associated with the development of subsequent solid cancer after allogeneic hematopoietic stem cell transplantation

BACKGROUND

An increased incidence of subsequent solid cancers (SSCs) has been reported in long-term survivors of allogeneic hematopoietic stem cell transplantation (allo-HSCT), and SSC is associated with inferior mortality and morbidity. Previous studies showed that the incidence of SSC is significantly higher in those who underwent allo-HSCT from HLA-mismatched donors, suggesting that persistent alloimmunity may predispose patients to SSCs. It was recently reported that, in a cohort of patients who received allo-HSCT from an unrelated donor matched at HLA-A, -B, -C, -DRB1/3/4/5, and -DQB1 loci, HLA-DPB1 alloimmunity determined by high mismatched eplets (MEs) and Predicted Indirectly Recognizable HLA Epitopes (PIRCHE) score (PS), was associated with relapse protection and increased risk of acute graft-versus-host disease (GVHD).

METHODS

In the present study, the impact of HLA-DPB1 alloimmunity assessed by molecular mismatch algorithms on the development of SSCs in a cohort of 1514 patients who underwent allo-HSCT for hematologic malignancies was further investigated. ME load at the HLA-DPB1 locus was measured using the HLAMatchmaker module incorporated in HLA Fusion software, and the PS for mismatched HLA-DPB1 was calculated using the HSCT module from the PIRCHE online matching service.

RESULTS

In multivariable analysis after adjusting for baseline risk factors, higher ME, PS-I, and PS-II in the GVH direction, but not in the HVG direction, were associated with an increased risk of SSCs (ME: subdistribution hazard ratio [SHR] 1.58, p = .01; PS-I: SHR 1.59, p = .009; PS-II: SHR 1.71, p = .003). In contrast, nonpermissive HLA-DPB1 mismatches defined by the conventional T-cell epitope algorithm were not predictive of the risk of SSCs. Moreover, posttransplant cyclophosphamide-based GVHD prophylaxis was associated with a reduced risk of subsequent solid cancer (SHR 0.34, p = .021).

CONCLUSIONS

These results indicate for the first time that increased GVH alloreactivity could contribute to the development of SSCs in allo-HSCT survivors.

Prolonged gut microbial alterations in post-transplant survivors of allogeneic haematopoietic stem cell transplantation

Dysbiosis of the gut microbiota has been reported to increase early complications after allogeneic haematopoietic stem cell transplantation (allo-HSCT). However, it remains unclear whether gut microbial alterations persist during late complications, such as chronic graft-versus-host disease (cGVHD) or secondary cancers. Here, we analysed the gut microbiota of 59 patients who survived for 1-21.7 years (median, 6.4 years) after allo-HSCT. Long-term survivors showed lower gut microbial diversity than the age- and sex-matched healthy controls. This decreased diversity was reflected in the reduced abundance of the butyrate-producing bacteria. Patients with a history of grade 3 acute graft-versus-host disease (aGVHD) exhibited higher Veillonella abundance than patients with a history of grade 1-2 or non-aGVHD cases. The abundance of Faecalibacterium showed no decrease only in limited cGVHD cases. Additionally, the microbial structure in the secondary cancer group was significantly different (p < 0.05) from that in the non-secondary cancer group. This study is the first to show that microbial dysbiosis is present over a 10-year lifetime after discharge following allo-HSCT. Our results suggest that these prolonged gut microbial alterations may be associated with the development and exacerbation of late complications in post-transplant survivors.

Risk of Secondary Non-hematologic Malignancies after Allogeneic Stem Cell Transplantation: A Nationwide Case-Control Cohort Study

This study investigated the incidence of secondary non-hematologic malignancies in patients undergoing allogeneic hematopoietic stem cell transplantation (allo-SCT) and explored its risk compared with the general population. A population-based case cohorts with adult patients who received allo-SCT between January 2002 and December 2018 and a control cohort with matched general population were extracted from the Korean National Health Insurance Service database. Each case and control cohort included 5177 patients. With a median follow-up of 2374 days for the case cohort and 2269 days for the control cohort, the 10-year cumulative incidence rate of non-hematologic malignancy was significantly higher in the case cohort compared with the control cohort (4.23% vs. 2.3%, hazard ratio (HR) 1.73, 95% confidence interval (CI) 1.32-2.25, p<0.001). The sub-class analysis according to cancer-site revealed significantly higher risks of 10-year cumulative incidence for cancers of head, neck, and esophagus (HR 3.19, 95% CI 1.34-7.59, p=0.003); cancers involving upper gastrointestinal tract (HR 3.74, 95% CI 1.58-8.85, p<0.001), colorectal cancer (HR 2.02, 95% CI 1.04-3.91, p=0.029), thyroid cancer (HR 2.09, 95% CI 1.1-3.97, p=0.012), gynecological cancer (HR 2.69, 95% CI 1.04-6.96, p=0.048) in the case cohort compared with the control cohort. No significant differences were detected for cancers involving lung, mediastinum, and heart, breast cancer in female, cancers of the hepatobiliary and pancreatic system, and cancers associated with urological system. These findings suggest the need for enhanced screening for non-hematologic malignancies in allo-SCT recipients compared with the general population. This article is protected by copyright. All rights reserved.

Male-specific late effects in adult hematopoietic cell transplantation recipients: a systematic review from the Late Effects and Quality of Life Working Committee of the Center for International Blood and Marrow Transplant Research and Transplant Complications Working Party of the European Society of Blood and Marrow Transplantation

Male-specific late effects after hematopoietic cell transplantation (HCT) include genital chronic graft-versus-host disease (GvHD), hypogonadism, sexual dysfunction, infertility, and subsequent malignancies. They may be closely intertwined and cause prolonged morbidity and decreased quality of life after HCT. We provide a systematic review of male-specific late effects in a collaboration between transplant physicians, endocrinologists, urologists, dermatologists, and sexual health professionals through the Late Effects and Quality of Life Working Committee of the Center for International Blood and Marrow Transplant Research, and the Transplant Complications Working Party of the European Society of Blood and Marrow Transplantation. The systematic review summarizes incidence, risk factors, screening, prevention and treatment of these complications and provides consensus evidence-based recommendations for clinical practice and future research.

Twenty years of experience of a tertiary cancer center in total body irradiation with focus on oncological outcome and secondary malignancies

Purpose

Total body irradiation (TBI) is a common part of the myelo- and immuno-ablative conditioning regimen prior to an allogeneic hematopoietic stem cell transplantation (allo-HSCT). Due to concerns regarding acute and long-term complications, there is currently a decline in otherwise successfully established TBI-based conditioning regimens. Here we present an analysis of patient and treatment data with focus on survival and long-term toxicity.

Methods

Patients with hematologic diseases who received TBI as part of their conditioning regimen prior to allo-HSCT at Frankfurt University Hospital between 1997 and 2015 were identified and retrospectively analyzed.

Results

In all, 285 patients with a median age of 45 years were identified. Median radiotherapy dose applied was 10.5 Gy. Overall survival at 1, 2, 5, and 10 years was 72.6, 64.6, 54.4, and 51.6%, respectively. Median follow-up of patients alive was 102 months. The cumulative incidence of secondary malignancies was 12.3% (n = 35), with hematologic malignancies and skin cancer predominating. A TBI dose ≥ 8 Gy resulted in significantly improved event-free (p = 0.030) and overall survival (p = 0.025), whereas a total dose ≤ 8 Gy and acute myeloid leukemia (AML) diagnosis were associated with significantly increased rates of secondary malignancies (p = 0.003, p = 0.048) in univariate analysis. No significant correlation was observed between impaired renal or pulmonary function and TBI dose.

Conclusion

TBI remains an effective and well-established treatment, associated with distinct late-toxicity. However, in the present study we cannot confirm a dose–response relationship in intermediate dose ranges. Survival, occurrence of secondary malignancies, and late toxicities appear to be subject to substantial confounding in this context.

Supplementary Information

The online version of this article (10.1007/s00066-022-01914-5) contains supplementary material, which is available to authorized users.

Long-term outcomes of lentiviral gene therapy for the β-hemoglobinopathies: the HGB-205 trial

Sickle cell disease (SCD) and transfusion-dependent β-thalassemia (TDT) are the most prevalent monogenic disorders worldwide. Trial HGB-205 ( NCT02151526 ) aimed at evaluating gene therapy by autologous CD34⁺ cells transduced ex vivo with lentiviral vector BB305 that encodes the anti-sickling β^A-T87Q-globin expressed in the erythroid lineage. HGB-205 is a phase 1/2, open-label, single-arm, non-randomized interventional study of 2-year duration at a single center, followed by observation in long-term follow-up studies LTF-303 ( NCT02633943 ) and LTF-307 ( NCT04628585 ) for TDT and SCD, respectively. Inclusion and exclusion criteria were similar to those for allogeneic transplantation but restricted to patients lacking geno-identical, histocompatible donors. Four patients with TDT and three patients with SCD, ages 13-21 years, were treated after busulfan myeloablation 4.6-7.9 years ago, with a median follow-up of 4.5 years. Key primary endpoints included mortality, engraftment, replication-competent lentivirus and clonal dominance. No adverse events related to the drug product were observed. Clinical remission and remediation of biological hallmarks of the disease have been sustained in two of the three patients with SCD, and frequency of transfusions was reduced in the third. The patients with TDT are all transfusion free with improvement of dyserythropoiesis and iron overload.

Case Report: Mevalonic Aciduria Complicated by Acute Myeloid Leukemia After Hematopoietic Stem Cell Transplantation

Mevalonic aciduria (MA) is the most severe clinical subtype of mevalonate kinase deficiency (MKD) caused by an inherited defect in the mevalonate pathway. The treatment of MKD focuses on the suppression of recurrent hyperinflammatory attacks using anti-inflammatory drugs. Recently, allogeneic hematopoietic stem cell transplantation (HCT) was shown to successfully ameliorate autoinflammatory attacks in patients with MKD. Here, we report a case of an infant who showed severe recurrent systemic inflammation and was diagnosed with MA. Although she responded to steroids, her symptoms relapsed after the dose was tapered, and organ deterioration occurred. Therefore, at the age of 11 months, HCT from a matched, unrelated donor was performed for curative treatment. However, at 50 days after transplantation, acute myeloid leukemia was diagnosed, which was chemo-refractory. A second HCT from her haploidentical father was performed to treat the acute myeloid leukemia, but the patient died of sepsis on day 4 after transplantation. This is the first report of malignancy following HCT for MA. Our findings suggest that normalizing the mevalonate pathway after HCT in patients with MKD impacts patients differently depending on the clinical spectrum and severity of disease.

Subsequent Cancers in Patients Affected with Moderate or Severe Chronic Graft-versus-Host Disease

Subsequent cancer (SC) is a significant cause of morbidity and mortality in long-term survivors after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Chronic graft-versus-host disease (cGVHD) and treatment-related immunosuppression have been recognized as risk factors for SC. This study sought to investigate the incidence and risk factors for SC in patients with established cGVHD, assessed separately for onset of basal cell carcinoma (BCC) and squamous cell carcinoma (SCC)-categorized into nonmelanoma skin cancer (NMSC)-and all cancers other than NMSC. Two hundred and four patients were enrolled in the prospective cross-sectional cGVHD Natural History Study and underwent comprehensive clinical evaluation. Patients were followed-up with an annual survey. The cumulative incidences of NMSC and cancers other than NMSC with competing risks were estimated separately, and transplantation- and cGVHD-related factors were assessed for association with outcomes using Gray's test and multivariable Cox models. The time period for all analyses began at 2 years postevaluation to restrict analyses to patients presumed to not have had SC present at evaluation. Nineteen patients were diagnosed with NMSC and 19 were diagnosed with cancers other than NMSC, with 10-year cumulative incidences of 15.5% (95% confidence interval, 9.0% to 27.6%) and 13.8% (95% CI, 8.2% to 20.8%), respectively. Age at transplantation (hazard ratio [HR], 1.94; 95% CI, 1.23 to 3.06) and higher C-reactive protein level at evaluation (HR, 9.49; 95% CI, 1.26 to 71.58) were jointly associated with NMSC, and gastrointestinal cGVHD at evaluation (HR, 0.26; 95% CI, 0.09 to 0.78) was associated with reduced risk of NMSC. T cell depletion at transplantation (HR, 3.09; 95% CI, 1.17 to 8.20), lymphoma as an indication for transplantation (HR, 3.96; 95% CI, 1.56 to 10.05), and oral cGVHD severity at evaluation (HR, 4.36; 95% CI, 1.52 to 12.46) were jointly associated with cancers other than NMSC. This study estimates the incidence of SC in a population of allo-HSCT recipients with severe cGVHD and identifies correlations with the subsequent development of SC. These factors seem to differ between NMSC and cancers other than NMSC. Further longitudinal investigations accounting for dynamic and cumulative processes are needed to improve our understanding and management of SC.

Male-specific late effects in adult hematopoietic cell transplantation recipients: a systematic review from the Late Effects and Quality of Life Working Committee of the Center for International Blood and Marrow Transplant Research and Transplant Complications Working Party of the European Society of Blood and Marrow Transplantation

BACKGROUND

Male-specific late effects after hematopoietic cell transplantation (HCT) include genital chronic graft-versus-host disease (GvHD), hypogonadism, sexual dysfunction, infertility, and subsequent malignancies, such as prostate, penile, and testicular cancer. They may be closely intertwined and cause prolonged morbidity and decreased quality of life after HCT.

OBJECTIVE

Here, we provide a systematic review of male-specific late effects in a collaboration between transplant physicians, endocrinologists, urologists, dermatologists, and sexual health professionals through the Late Effects and Quality of Life Working Committee of the Center for International Blood and Marrow Transplant Research, and the Transplant Complications Working Party of the European Society of Blood and Marrow Transplantation.

STUDY DESIGN

We utilized systematic review methodology to summarize incidence, risk factors, screening, prevention and treatment of these complications and provide consensus evidence-based recommendations for clinical practice and future research.

RESULTS

Most of the evidence regarding male GvHD is still based on limited data, precluding strong therapeutic recommendations. We therefore recommend to systematically screen for male genital GvHD regularly and report it to large registries to allow for a better understanding. Future research should also address treatment since little published evidence is available to date. Male-specific endocrine consequences of HCT include hypogonadism which may also affect bone health. Since the evidence is scarce, current recommendations for hormone substitution and/or bone health treatment are based on similar principles as for the general population. Following HCT, sexual health decreases and this topic should be addressed at regular intervals. Future studies should focus on interventional strategies to address sexual dysfunction. Infertility remains prevalent in patients having undergone myeloablative conditioning, which warrants offering sperm preservation in all HCT candidates. Most studies on fertility rely on descriptive registry analysis and surveys, hence the importance of reporting post-HCT conception data to large registries. Although the quality of evidence is low, the development of cancer in male genital organs does not seem more prevalent than in the general population; however, subsequent malignancies in general seem to be more prevalent in males than females, and special attention should be given to skin and oral mucosa.

CONCLUSION

Male-specific late effects, probably more under-reported than female-specific complications, should be systematically considered during the regular follow-up visits of male survivors who have undergone HCT. Care of patients with male-specific late effects warrants close collaboration between transplant physicians and specialists from other involved disciplines. Future research should be directed towards better data collection on male-specific late effects and on studies about the interrelationship between these late effects, to allow the development of evidence based effective management practices.

Application of Photodynamic Therapy with 5-Aminolevulinic Acid to Extracorporeal Photopheresis in the Treatment of Patients with Chronic Graft-versus-Host Disease: A First-in-Human Study

Extracorporeal photopheresis (ECP), an immunomodulatory therapy for the treatment of chronic graft-versus-host disease (cGvHD), exposes isolated white blood cells to photoactivatable 8-methoxypsoralen (8-MOP) and UVA light to induce the apoptosis of T-cells and, hence, to modulate immune responses. However, 8-MOP-ECP kills diseased and healthy cells with no selectivity and has limited efficacy in many cases. The use of 5-aminolevulinic acid (ALA) and light (ALA-based photodynamic therapy) may be an alternative, as ex vivo investigations show that ALA-ECP kills T-cells from cGvHD patients more selectively and efficiently than those treated with 8-MOP-ECP. The purpose of this phase I-(II) study was to evaluate the safety and tolerability of ALA-ECP in cGvHD patients. The study included 82 treatments in five patients. One patient was discharged due to the progression of the haematological disease. No significant persistent changes in vital signs or laboratory values were detected. In total, 62 adverse events were reported. Two events were severe, 17 were moderate, and 43 were mild symptoms. None of the adverse events evaluated by the internal safety review committee were considered to be likely related to the study medication. The results indicate that ALA-ECP is safe and is mainly tolerated well by cGvHD patients.

Two Lip Carcinomas following Allogeneic Hematopoietic Stem Cell Transplantation: A Case Report and Literature Review

Background

Secondary solid cancers are severe complications in patients who have undergone allogeneic hematopoietic stem cell transplantation (AHSCT) for malignant and nonmalignant lymphohematopoietic diseases.

Objective

The aim of this work was to report a case of two lip carcinomas following AHSCT and to warn doctors about the importance of regular check-ups of patients who have received HSCT. Observation. A 57-year-old man was referred by the dermatology department for the management of exophytic budding lesions on the lower lip evolving since 5 months. The patient was in complete remission following allogeneic bone marrow transplantation for acute myeloid leukemia since five years. Clinical and histological findings confirmed the diagnosis of a squamous cell carcinoma of the two lesions.

Conclusion

It is of paramount importance to seek an oral squamous cell carcinoma in the presence of persistent lesions in HSCT recipients.

Primary mesenchymal stromal cells in co-culture with leukaemic HL-60 cells are sensitised to cytarabine-induced genotoxicity, whilst leukaemic cells are protected

Tumour microenvironments are hallmarked in many cancer types. In haematological malignancies, bone marrow (BM) mesenchymal stromal cells (MSC) protect malignant cells from drug-induced cytotoxicity. However, less is known about malignant impact on supportive stroma. Notably, it is unknown whether these interactions alter long-term genotoxic damage in either direction. The nucleoside analogue cytarabine (ara-C), common in haematological therapies, remains the most effective agent for acute myeloid leukaemia, yet one third of patients develop resistance. This study aimed to evaluate the bidirectional effect of MSC and malignant cell co-culture on ara-C genotoxicity modulation. Primary MSC, isolated from patient BM aspirates for haematological investigations, and malignant haematopoietic cells (leukaemic HL-60) were co-cultured using trans-well inserts, prior to treatment with physiological dose ara-C. Co-culture genotoxic effects were assessed by micronucleus and alkaline comet assays. Patient BM cells from chemotherapy-treated patients had reduced ex vivo survival (P = 0.0049) and increased genotoxicity (P = 0.3172) than untreated patients. It was shown for the first time that HL-60 were protected by MSC from ara-C-induced genotoxicity, with reduced MN incidence in co-culture as compared to mono-culture (P = 0.0068). Comet tail intensity also significantly increased in ara-C-treated MSC with HL-60 influence (P = 0.0308). MSC sensitisation to ara-C genotoxicity was also demonstrated following co-culture with HL60 (P = 0.0116), which showed significantly greater sensitisation when MSC-HL-60 co-cultures were exposed to ara-C (P = 0.0409). This study shows for the first time that malignant HSC and MSC bidirectionally modulate genotoxicity, providing grounding for future research identifying mechanisms of altered genotoxicity in leukaemic microenvironments. MSC retain long-term genotoxic and functional damage following chemotherapy exposure. Understanding the interactions perpetuating such damage may inform modifications to reduce therapy-related complications, such as secondary malignancies and BM failure.

Non-genotoxic conditioning facilitates hematopoietic stem cell gene therapy for hemophilia A using bioengineered factor VIII

Hematopoietic stem and progenitor cell (HSPC) lentiviral gene therapy is a promising strategy toward a lifelong cure for hemophilia A (HA). The primary risks associated with this approach center on the requirement for pre-transplantation conditioning necessary to make space for, and provide immune suppression against, stem cells and blood coagulation factor VIII, respectively. Traditional conditioning agents utilize genotoxic mechanisms of action, such as DNA alkylation, that increase risk of sterility, infection, and developing secondary malignancies. In the current study, we describe a non-genotoxic conditioning protocol using an immunotoxin targeting CD117 (c-kit) to achieve endogenous hematopoietic stem cell depletion and a cocktail of monoclonal antibodies to provide transient immune suppression against the transgene product in a murine HA gene therapy model. This strategy provides high-level engraftment of hematopoietic stem cells genetically modified ex vivo using recombinant lentiviral vector (LV) encoding a bioengineered high-expression factor VIII variant, termed ET3. Factor VIII procoagulant activity levels were durably elevated into the normal range and phenotypic correction achieved. Furthermore, no immunological rejection or development of anti-ET3 immunity was observed. These preclinical data support clinical translation of non-genotoxic antibody-based conditioning in HSPC LV gene therapy for HA.

Adverse Effects of Busulfan Plus Cyclophosphamide versus Busulfan Plus Fludarabine as Conditioning Regimens for Allogeneic Bone Marrow Transplantation

BACKGROUND

The side effects of conditioning regimens on the success rate of allogeneic transplantation around the world have been challenging. In this study, we aimed to investigate the side effect of Bu/Cy and Bu/Flu regimens on our patients who underwent allogeneic bone marrow transplantation.

METHODS

We analyzed 180 patients receiving bone marrow transplantation in Taleghani Hospital, in Tehran, Iran between April 2016 and December 2019. Patients in group A received a combination of intravenous busulfan 0.8 mg/kg QID over two hours for 4 consecutive days (12.8 mg/kg in total)(Savani et al., 2006) and cyclophosphamide 60 mg/kg per day for two consecutive days. Patients in group B received busulfan the same as the first group in combination with fludarabine equal to 40 mg/m² per day. Patients were followed up at regular intervals up to two years after transplantation.

RESULT

Various items were evaluated for patients, including cardiopulmonary function, psychological disorders, GVHD, and endocrine disorders such as hypothyroidism, fertility, or gonad dysfunction.  Primary hypothyroidism developed in 13.3% and 11.1% of the Bu/Cy and Bu/Flu groups, respectively (p=0.230). None of the patients in either group experienced infertility or gonad dysfunction. In group A versus group B, pulmonary diseases were detected in  4.4% versus 6.6% of BMT recipients, respectively (p = 0.223). In both groups, mitral and tricuspid regurgitation were observed in patients (8.9% vs. 11.1%; p = 0.189). Incidence of Psychological disorders was no significant difference between the two groups. 32.2% of group A versus 34.45%  of group B had skin and liver GVHD, respectively (p = 0.235).

CONCLUSION

The therapeutic-related adverse effects of the two conditioning regimens in patients who underwent allogeneic bone marrow transplant were almost similar. To improve quality of life and overall survival among BMT patients, careful evaluation of treatment-related complications should be part of the regular follow-up of them.

The risk of malignancies in patients receiving hematopoietic stem cell transplantation: a systematic review and meta-analysis

INTRODUCTION

Hematopoietic stem cell transplantation (HSCT) is widely used in the treatment of malignant and non-malignant diseases. Due to advances in the number of survivors of this treatment, the number of survivors is increasing, but the late complications of this therapeutic approach such as secondary cancers have been long term and have not been fully controlled.

METHODS

The present meta-analysis study was performed by considering English-language articles in the databases including Web of Science, Scopus and PubMed. This meta-analysis included cohort studies that reported an incidence of cancer following stem cell transplantation (SCT). Random/fixed effect size meta-analyses were used to standardize the incidence ratio for different cancers.

RESULTS

22 studies that evaluated patients receiving SCT (n = 270,063) were included in the study. The study found 9233 cases of cancer after transplantation. Meta-analysis showed that the risk of cancer after SCT was SIR = 1.66 (95% CI 1.47-1.86). The most common cancers observed in SCT recipients were bone tissue, head and neck cancers, and melanoma, with SIRs of 10.04 (3.48-16.61), 6.35 (4.76-7.93) and 3.52 (2.65-4.39), respectively.

CONCLUSION

The meta-analysis findings showed that the risk of secondary cancers after HSCT was significantly increased in most types of cancers. Consequently, diagnostic tests for common cancers should be included in the screening program of these patients for the prevention and early detection of high-risk cancers.

Malignancy post-hematopoietic stem cell transplant in patients with primary immunodeficiency

INTRODUCTION

Hematopoietic cell transplantation (HCT) is a curative treatment for an expanding number of primary immunodeficiencies (PIDs). Malignancies are more common in patients with PID than in the general population, and this review will discuss whether a successful HCT is expected to abolish or alter this risk. Second malignancy post HCT for a malignant disease is well known to occur, but generally less expected in patients transplanted for PID.

AREAS COVERED

This article reviews recently published literature focusing on the pattern of malignancy in children with PID, incidence, and risk factors for developing malignancy post-HCT for PID and possible strategies to reduce the risks.

EXPERT OPINION

Survival post HCT for PID has improved dramatically in the last 20 years and the genomic revolution has led to an expanding number of indications. To improve long-term quality of life attention needs to focus on late effects, including the possibility of malignancy occurring more frequently than expected in the general population, understand the risks and improve the process of transplantation in order to minimize them. Further studies are needed.

Optimal Delivery of Follow-Up Care After Allogeneic Hematopoietic Stem-Cell Transplant: Improving Patient Outcomes with a Multidisciplinary Approach

The increasing indications for allogeneic stem-cell transplant in patients with hematologic malignancies and non-malignant diseases combined with improved clinical outcomes have contributed to increase the number of long-term survivors. However, survivors are at increased risk of developing a unique set of complications and late effects, besides graft-versus-host disease and disease relapse. In this setting, the management capacity of a single health-care provider can easily be overwhelmed. Thus, to provide appropriate survivorship care, a multidisciplinary approach for the long-term follow-up is essential. This review aims at summarizing the most relevant information that a health-care provider should know to establish a follow-up care plan, in the light of individual exposures and risk factors, that includes all organ systems and considers the psychological burden of these patients.

Premature ageing following allogeneic hematopoietic stem cell transplantation

Survivors of hematopoietic cell transplantation (HCT) have been shown to exhibit both clinical and biological features of accelerated ageing. Most studies used frailty measures, comorbidities for clinical assessment and several biological assessment of premature ageing. However, these tests are less suitable for age determination of individual patients. Recently, DNA methylation has emerged as a novel test to measure cellular age. In the present study, we assessed ageing in a cohort of 26 survivors of allogeneic HCT by frailty tests comprising the handgrip and 6 min walk tests and by biological tests including DNA methylation, telomere length and expression of p16INK^4A and serum levels of IL-6. DNA methylation was evaluated both in blood and buccal epithelial cells. Physiological reserve was markedly reduced in transplant survivors, reflected by 6 min walk test. Increased IL-6 serum levels and p16^ink4A correlated with accelerated ageing. Overall, the measured age of donor blood cells was significantly higher than these blood cells residing in their respective donors, as reflected by DNA methylation and by buccal epithelium methylation status. These clinical and biological observations suggest that allogeneic HCT is associated with accelerated ageing.

Lower Genital Tract Precancer and Cancer in Hematopoietic Cell Transplant Survivors and the Role of HPV: A Systematic Review and Future Perspectives

Female recipients of hematopoietic cell transplant (HCT) may develop lower genital tract (LGT) dysplasia or new malignancies. A comprehensive systematic review to delineate the occurrence and risk factors for post-HCT LGT precancer and cancer in women was conducted via electronic search of the Cochrane Library, PubMed, Embase, Wiley Online Library, from 1990 to 2018. All studies on the risk, presentation, or incidence of LGT (cervix, vulva, vagina) precancer or cancer post-HCT were included. Reviews, case reports, meta-analysis, book chapters, and studies without the relevant clinical outcomes were excluded. Post-HCT incidence and risk factors for developing LGT precancer or cancer were assessed and determined. Twenty-two out of the original 344 studies met the selection criteria. The risk of LGT cancers in allo-HCT recipients was found to be significantly higher than in the general population, with the standardized incidence ratios of 1.5–48 for cervical cancer and from 19 to 287 for dysplasia. Our review portrays an increased risk of premalignant and malignant neoplasms of female LGT, which have an incompletely described epidemiology and outcomes. Similar to other immunocompromised states, HCT recipients require specific cervical screening guidelines and can greatly benefit from HPV vaccinations. However, there is a lack of prospective data regarding optimum cervical screening in HCT recipients and limited programs offer HPV vaccinations worldwide.

Reduced-Intensity Conditioning Regimens, Prior Chronic Lymphocytic Leukemia, and Graft-Versus-Host Disease Are Associated with Higher Rates of Skin Cancer after Allogeneic Hematopoietic Stem Cell Transplantation

To assess incidence and risk factors for skin cancer associated with allogeneic hematopoietic stem cell transplantation, we evaluated 1,974 adult allogeneic hematopoietic stem cell transplantation patients from Beth Israel Deaconess Medical Center and Dana-Farber Cancer Institute who received transplants between January 1995 and July 2013 for hematologic malignancy and survived at least 100 days. Median age was 51.1 years, and median follow-up time was 3 years. Overall, 119 patients had 221 skin cancers. The incidences of squamous cell carcinomas (incidence rate ratio = 9.8; 95% confidence interval = 7.7-12.3), basal cell carcinomas (incidence rate ratio = 2.5; 95% confidence interval = 1.9-3.2), and melanoma (standardized incidence ratio = 3.3; 95% confidence interval = 1.7-5.9) were elevated in our cohort. In multivariable models, risk factors for squamous cell carcinomas were increased age (P < 0.0001), chronic lymphocytic leukemia (P = 0.02), and chronic graft-versus-host disease (P = 0.0002). Risk factors for basal cell carcinomas were chronic lymphocytic leukemia (P = 0.003), reduced-intensity conditioning (P = 0.02), acute graft-versus-host disease (P = 0.03), and chronic graft-versus-host disease (P = 0.003). To our knowledge, previously unreported risk factors in this contemporary cohort include prior CLL for squamous cell carcinoma and basal cell carcinoma and reduced-intensity conditioning for basal cell carcinoma. This study also supports chronic graft-versus-host disease as a risk factor for nonmelanoma skin cancer, particularly squamous cell carcinoma.

Clinicopathologic characteristics of secondary squamous cell carcinoma of head and neck in survivors of allogeneic hematopoietic stem cell transplantation for hematologic malignancies

The risk of late complications including secondary malignancies is increased in long-term survivors of allogeneic hematopoietic stem cell transplants (HSCT). There is limited literature on the biological behavior and clinical features of squamous cell carcinoma (SCC) of head and neck post-HSCT. We present the clinical and pathologic characteristics on six patients who were diagnosed with SCC while in remission following an allogeneic HSCT. Median follow-up was 8 years. Five patients (83%) developed SCC of tongue and one developed esophageal SCC. Five patients had oral chronic graft-versus-host disease (cGvHD). The conventional risk factors of alcohol, tobacco, and human papillomavirus were absent. The most common presenting finding was the new-onset focal oral pain and ulcerated plaques clinically indistinguishable from a flare of their oral cGvHD lesions. We demonstrated that the SCC in three patients was of donor origin.

Second Malignancies after Hematopoietic Stem Cell Transplantation

OPINION STATEMENT

Second malignancies are a rare but well-defined late complication after autologous and allogeneic hematopoietic stem-cell transplantation (SCT). Solid malignancies occur in up to 15% of patients 15 years after SCT with myeloablative conditioning, with no plateau in the incidence rates. They are responsible for 5-10% of late deaths after SCT. The incidence is increased with advanced age at SCT. The major risk factors are the use of total body irradiation, which is associated with adenocarcinomas and with chronic graft-versus-host disease which is associated with squamous cell cancers. There is less data on the incidence of second malignancies after reduced-intensity conditioning, but it may not be lower. The types of solid tumors reported in excess include melanoma and other skin cancers; cancers of the oral cavity and head and neck, brain, liver, uterine cervix, thyroid, breast, lung; and possibly gastrointestinal cancers. Therapy-related myeloid neoplasms (t-MN) are more common after autologous SCT and may be related mostly to pre-transplant therapies. Post-transplant lymphoproliferative disease is donor-cell-derived lymphoma that is more common after allogeneic SCT with T-cell depletion or intensive immune-suppression state. Second malignancies are most often treated similarly to the standard therapy for similar malignancies. Lifelong cancer screening and prevention interventions are required for all transplantation survivors.

National Institutes of Health Hematopoietic Cell Transplantation Late Effects Initiative: The Subsequent Neoplasms Working Group Report

Subsequent neoplasms (SN) after hematopoietic cell transplantation (HCT) cause significant patient morbidity and mortality. Risks for specific SN types vary substantially, with particularly elevated risks for post-transplantation lymphoproliferative disorders, myelodysplastic syndrome/acute myeloid leukemia, and squamous cell malignancies. This document provides an overview of the current state of knowledge regarding SN after HCT and recommends priorities and approaches to overcome challenges and gaps in understanding. Numerous factors have been suggested to affect risk, including patient-related (eg, age), primary disease-related (eg, disease type, pre-HCT therapies), and HCT-related characteristics (eg, type and intensity of conditioning regimen, stem cell source, development of graft-versus-host disease). However, gaps in understanding remain for each of these risk factors, particularly for patients receiving HCT in the current era because of substantial advances in clinical transplantation practices. Additionally, the influence of nontransplantation-related risk factors (eg, germline genetic susceptibility, oncogenic viruses, lifestyle factors) is poorly understood. Clarification of the magnitude of SN risks and identification of etiologic factors will require large-scale, long-term, systematic follow-up of HCT survivors with detailed clinical data. Most investigations of the mechanisms of SN pathogenesis after HCT have focused on immune drivers. Expansion of our understanding in this area will require interdisciplinary laboratory collaborations utilizing measures of immune function and availability of archival tissue from SN diagnoses. Consensus-based recommendations for optimal preventive, screening, and therapeutic approaches have been developed for certain SN after HCT, whereas for other SN, general population guidelines are recommended. Further evidence is needed to specifically tailor preventive, screening, and therapeutic guidelines for SN after HCT, particularly for unique patient populations. Accomplishment of this broad research agenda will require increased investment in systematic data collection with engagement from patients, clinicians, and interdisciplinary scientists to reduce the burden of SN in the rapidly growing population of HCT survivors.

Long-Term Incidence of Secondary Malignancies after Allogeneic Hematopoietic Cell Transplantation: A Single-Center Experience

To review the emergence of secondary malignancies (SMs) in recipients of allogeneic hematopoietic cell transplantation (HCT), we documented the occurrence of SMs in 2415 allogeneic HCT recipients, ages 18 to 71, in a single center over 4 decades. SMs were seen in 209 patients, including 58 with nonmetastatic squamous cell (SCC) and basal cell carcinoma (BCC) of the skin. Cumulative incidence of SM was 6.3% at 10 years, 13.5% at 20 years, and 17.6% at 30 years post-HCT. Median age at diagnosis of SMs was 61 years (range, 21 to 85). By multivariable analysis, older age at HCT was the only independent prognostic factor for SM (HR, 1.39 for ages 41 to 55 and HR, 1.92 for age > 55 compared with age ≤ 40; P = .001). The rate of SM (excluding nonmetastatic SCC/BCC of skin) after HCT was 2.07 times higher (P = .01) compared with the general population. Overall survival (OS) after diagnosis of SM (excluding nonmetastatic SCC/BCC of skin) was 58% at 5 years and 50% at 10 years postdiagnosis. Eastern Cooperative Oncology Group (ECOG) score was the only independent predictor of OS on multivariable analysis, with over 2-fold increased risk of death for patients with an ECOG score of 1 and over 6-fold for ECOG scores of 2 to 4, compared with ECOG score 0 (P < .0001). Forty of 209 patients (19%) diagnosed with SMs subsequently developed another new malignancy. OS was 68% and 51% at 5 and 10 years, respectively. The survival of SM patients post-HCT is favorable, thus warranting diligent long-term cancer screening and standard of care treatment. ECOG status of these patients is a predominant prognostic factor.

Long-term survival and late events after allogeneic stem cell transplantation from HLA-matched siblings for acute myeloid leukemia with myeloablative compared to reduced-intensity conditioning: a report on behalf of the acute leukemia working party of European group for blood and marrow transplantation

Background

Myeloablative (MAC) and reduced-intensity conditioning (RIC) are established approaches for allogeneic stem cell transplantation (SCT) in acute myeloid leukemia (AML). Most deaths after MAC occur within the first 2 years after SCT, while patients surviving leukemia-free for 2 years can expect a favorable long-term outcome. However, there is paucity of data on the long-term outcome (beyond 10 years) and the pattern of late events following RIC due to the relative recent introduction of this approach.

Methods

We analyzed long-term outcomes in a cohort of 1423 AML patients, age ≥50 years, after SCT from HLA-matched siblings, during the years 1997–2005, median follow-up 8.3 years (0.1–17).

Results

The 10-year leukemia-free survival (LFS) was 31 % (95CI, 27–35) and 32 % (28–35) after MAC and RIC, respectively (P = 0.57). The 10-year GVHD/ relapse-free survival (GRFS), a surrogate for quality of life was 22 % (18–25) and 21 % (18–24), respectively (P = 0.79). The 10-year non-relapse mortality (NRM) was higher and relapse rate was lower after MAC, throughout the early and late post-transplant course. The 10-year LFS among 584 patients surviving leukemia-free 2 years after SCT was 71 % (65–76) and 73 % (67–78) after MAC and RIC, respectively (P = 0.76). Advanced leukemia at SCT was the major predictor of LFS subsequent to the 2-year landmark. Relapse was the major cause of late death after both regimens; however, NRM and in particular chronic graft-versus-host disease and second cancers were more common causes of late death after MAC.

Conclusions

Long-term LFS and GRFS are similar after RIC and MAC. Most events after RIC or MAC occur within the first 2 years after SCT. Patients who are leukemia-free 2 years after SCT can expect similar good subsequent outcome after both approaches.

Electronic supplementary material

The online version of this article (doi:10.1186/s13045-016-0347-1) contains supplementary material, which is available to authorized users.

Reduced intensity conditioning allogeneic hematopoietic cell transplantation for adult acute myeloid leukemia in complete remission - a review from the Acute Leukemia Working Party of the EBMT

Acute myeloid leukemia is the most common indication for an allogeneic hematopoietic cell transplant. The introduction of reduced intensity conditioning has expanded the recipient pool for transplantation, which has importantly made transplant an option for the more commonly affected older age groups. Reduced intensity conditioning allogeneic transplantation is currently the standard of care for patients with intermediate or high-risk acute myeloid leukemia and is now most often employed in older patients and those with medical comorbidities. Despite being curative for a significant proportion of patients, post-transplant relapse remains a challenge in the reduced intensity conditioning setting. Herein we discuss the studies that demonstrate the feasibility of reduced intensity conditioning allogeneic transplants, compare the outcomes of reduced intensity conditioning versus chemotherapy and conventional myeloablative conditioning regimens, describe the optimal donor and stem cell source, and consider the impact of post-remission consolidation, comorbidities, center experience, and more intensive (reduced toxicity conditioning) regimens on outcomes. Additionally, we discuss the need for further prospective studies to optimize transplant outcomes.

Risk of secondary solid malignancies after allogeneic hematopoietic stem cell transplantation and preventive strategies

The risk of secondary solid malignancies is increased after allogeneic hematopoietic stem cell transplantation (HSCT). The risk starts at about 10 years after HSCT and continues even 20 years later. The most common secondary malignancies include squamous cell carcinoma of skin, genitourinary tract and oral cavity; lung and breast cancers. The use of total body irradiation or conditioning chemotherapy, chronic graft-versus-host disease and duration since HSCT can influence the risk of secondary solid malignancies. Secondary solid malignancies are common causes of nonrelapse mortality in long-term survivors and may account for up to 10% of late deaths. Avoiding smoking, alcohol use and excess sun exposure may reduce the risk. Cancer prevention guidelines are largely consensus-driven and follow the recommendations for general population.

Similar outcome of upfront-unrelated and matched sibling stem cell transplantation in idiopathic paediatric aplastic anaemia. A study on behalf of the UK Paediatric BMT Working Party, Paediatric Diseases Working Party and Severe Aplastic Anaemia Working Party of EBMT

We explored the feasibility of unrelated donor haematopoietic stem cell transplant (HSCT) upfront without prior immunosuppressive therapy (IST) in paediatric idiopathic severe aplastic anaemia (SAA). This cohort was then compared to matched historical controls who had undergone first-line therapy with a matched sibling/family donor (MSD) HSCT (n = 87) or IST with horse antithymocyte globulin and ciclosporin (n = 58) or second-line therapy with unrelated donor HSCT post-failed IST (n = 24). The 2-year overall survival in the upfront cohort was 96 ± 4% compared to 91 ± 3% in the MSD controls (P = 0·30) and 94 ± 3% in the IST controls (P = 0·68) and 74 ± 9% in the unrelated donor HSCT post-IST failure controls (P = 0·02).The 2-year event-free survival in the upfront cohort was 92 ± 5% compared to 87 ± 4% in MSD controls (P = 0·37), 40 ± 7% in IST controls (P = 0·0001) and 74 ± 9% in the unrelated donor HSCT post-IST failure controls (n = 24) (P = 0·02). Outcomes for upfront-unrelated donor HSCT in paediatric idiopathic SAA were similar to MSD HSCT and superior to IST and unrelated donor HSCT post-IST failure. Front-line therapy with matched unrelated donor HSCT is a novel treatment approach and could be considered as first-line therapy in selected paediatric patients who lack a MSD.

Leukemogenic rearrangements at the mixed lineage leukemia gene (MLL)-multiple rather than a single mechanism

Despite manifold efforts to achieve reduced-intensity and -toxicity regimens, secondary leukemia has remained the most severe side effect of chemotherapeutic cancer treatment. Rearrangements involving a short telomeric <1 kb region of the mixed lineage leukemia (MLL) gene are the most frequently observed molecular changes in secondary as well as infant acute leukemia. Due to the mode-of-action of epipodophyllotoxins and anthracyclines, which have widely been used in cancer therapy, and support from in vitro experiments, cleavage of this MLL breakpoint cluster hotspot by poisoned topoisomerase II was proposed to trigger the molecular events leading to malignant transformation. Later on, clinical patient data and cell-based studies addressing a wider spectrum of stimuli identified cellular stress signaling pathways, which create secondary DNA structures, provide chromatin accessibility, and activate nucleases other than topoisomerase II at the MLL. The MLL destabilizing signaling pathways under discussion, namely early apoptotic DNA fragmentation, transcription stalling, and replication stalling, may all act in concert upon infection-, transplantation-, or therapy-induced cell cycle entry of hematopoietic stem and progenitor cells (HSPCs), to permit misguided cleavage and error-prone DNA repair in the cell-of-leukemia-origin.

Secondary Malignant Neoplasms Following Haematopoietic Stem Cell Transplantation in Childhood

Improving survival rates in children with malignancy have been achieved at the cost of a high frequency of late adverse effects of treatment, especially in intensively treated patients such as those undergoing haematopoietic stem cell transplantation (HSCT), many of whom suffer the high burden of chronic toxicity. Secondary malignant neoplasms (SMNs) are one of the most devastating late effects, cause much morbidity and are the most frequent cause of late (yet still premature) treatment-related mortality. They occur in up to 7% of HSCT recipients by 20 years post-HSCT, and with no evidence yet of a plateau in incidence with longer follow-up. This review describes the epidemiology, pathogenesis, clinical features and risk factors of the three main categories of post-HSCT SMNs. A wide range of solid SMNs has been described, usually occurring 10 years or more post-HSCT, related most often to previous or conditioning radiotherapy. Therapy-related acute myeloid leukaemia/myelodysplasia occurs earlier, typically three to seven years post-HSCT, mainly in recipients of autologous transplant and is related to previous alkylating agent or topoisomerase II inhibitor chemotherapy. Post-transplant lymphoproliferative disorders occur early (usually within two years) post-HSCT, usually presenting as Epstein-Barr virus-related B cell non-Hodgkin lymphoma.

Allogeneic stem cell transplantation for refractory acute myeloid leukemia: a single center analysis of long-term outcome

For patients with refractory acute myeloid leukemia (AML), allogeneic stem cell transplantation (alloSCT) represents the only curative approach. We here analyzed the long-term outcome of 131 consecutive patients with active AML, which was either primary refractory or unresponsive to salvage chemotherapy, transplanted at our center between 1997 and 2013. After a median follow-up of 48 months for the surviving patients, disease-free survival (DFS) at 5 yr post alloSCT was 26% (94% CI: 17-35). Relapses, most of which occurred within the first 2 yr from transplant, were the predominant cause of treatment failure affecting 48% (95%CI: 40-58) of patients, whereas non-relapse mortality was 26% (95%CI: 20-36) at 5 yr and thereafter. A marrow blast count ≥20% before alloSCT was an independent prognosticator associated with an inferior DFS (HR: 1.58, P = 0.027), whereas the development of chronic graft-versus-host disease (cGvHD) predicted an improved DFS (HR 0.21, P < 0.001) and a decreased relapse incidence (HR: 0.18, P = 0.026), respectively. These results indicate that alloSCT represents a curative treatment option in a substantial proportion of patients with refractory AML. A pretransplant blast count <20% before alloSCT and the development of cGvHD are the most important predictors of long-term disease control.

Reduced-intensity conditioned allogeneic SCT in adults with AML

AML is currently the most common indication for reduced-intensity conditioned (RIC) allo-SCT. Reduced-intensity regimens allow a potent GVL response to occur with minimized treatment-related toxicity in patients of older age or with comorbidities that preclude the use of myeloablative conditioning. Whether RIC SCT is appropriate for younger and more standard risk patients is not well defined and the field is changing rapidly; a prospective randomized trial of myeloablative vs RIC (BMT-CTN 0901) was recently closed when early results indicated better outcomes for myeloablative regimens. However, detailed results are not available, and all patients in that study were eligible for myeloablative conditioning. RIC transplants will likely remain the standard of care as many patients with AML are not eligible for myeloablative conditioning. Recent publication of mature results from retrospective and prospective cohorts provide contemporary efficacy and toxicity data for these attenuated regimens. In addition, recent studies explore the use of alternative donors, introduce regimens that attempt to reduce toxicity without reducing intensity, and identify predictive factors that pave the way to personalized approaches. These studies paint a picture of the future of RIC transplants. Here we review the current status of RIC allogeneic SCT in AML.

Second solid cancers after allogeneic hematopoietic cell transplantation using reduced-intensity conditioning

We examined risk of second solid cancers after allogeneic hematopoietic cell transplantation (AHCT) using reduced-intensity/nonmyeloablative conditioning (RIC/NMC). RIC/NMC recipients with leukemia/myelodysplastic syndrome (MDS) (n = 2833) and lymphoma (n = 1436) between 1995 and 2006 were included. In addition, RIC/NMC recipients 40 to 60 years of age (n = 2138) were compared with patients of the same age receiving myeloablative conditioning (MAC, n = 6428). The cumulative incidence of solid cancers was 3.35% at 10 years. There was no increase in overall cancer risk compared with the general population (leukemia/MDS: standardized incidence ratio [SIR] .99, P = 1.00; lymphoma: SIR .92, P = .75). However, risks were significantly increased in leukemia/MDS patients for cancers of lip (SIR 14.28), tonsil (SIR 8.66), oropharynx (SIR 46.70), bone (SIR 23.53), soft tissue (SIR 12.92), and vulva (SIR 18.55) and skin melanoma (SIR 3.04). Lymphoma patients had significantly higher risks of oropharyngeal cancer (SIR 67.35) and skin melanoma (SIR 3.52). Among RIC/NMC recipients, age >50 years was the only independent risk factor for solid cancers (hazard ratio [HR] 3.02, P < .001). Among patients ages 40 to 60 years, when adjusted for other factors, there was no difference in cancer risks between RIC/NMC and MAC in leukemia/MDS patients (HR .98, P = .905). In lymphoma patients, risks were lower after RIC/NMC (HR .51, P = .047). In conclusion, the overall risks of second solid cancers in RIC/NMC recipients are similar to the general population, although there is an increased risk of cancer at some sites. Studies with longer follow-up are needed to realize the complete risks of solid cancers after RIC/NMC AHCT.

Inhibition of protein geranylgeranylation specifically interferes with CD40-dependent B cell activation, resulting in a reduced capacity to induce T cell immunity

Ab-independent effector functions of B cells, such as Ag presentation and cytokine production, have been shown to play an important role in a variety of immune-mediated conditions such as autoimmune diseases, transplant rejection, and graft-versus-host disease. Most current immunosuppressive treatments target T cells, are relatively unspecific, and result in profound immunosuppression that places patients at an increased risk of developing severe infections and cancer. Therapeutic strategies, which interfere with B cell activation, could therefore be a useful addition to the current immunosuppressive armamentarium. Using a transcriptomic approach, we identified upregulation of genes that belong to the mevalonate pathway as a key molecular event following CD40-mediated activation of B cells. Inhibition of 3-hydroxy-3-methylglutaryl CoA reductase, the rate-limiting enzyme of the mevalonate pathway, by lipophilic statins such as simvastatin and atorvastatin resulted in a specific inhibition of B cell activation via CD40 and impaired their ability to act as stimulatory APCs for allospecific T cells. Mechanistically, the inhibitory effect resulted from the inhibition of protein geranylgeranylation subsequent to the depletion of mevalonate, the metabolic precursor for geranylgeranyl. Thus, inhibition of geranylgeranylation either directly through geranylgeranyl transferase inhibitors or indirectly through statins represents a promising therapeutic approach for the treatment of diseases in which Ag presentation by B cells plays a role.