Therapy-related acute promyelocytic leukemia: observations relating to APL pathogenesis and therapy

The impact of obesity-induced inflammation on clonal hematopoiesis

PURPOSE OF REVIEW

This review meticulously delves into existing literature and recent findings to elucidate the intricate link between obesity and clonal hematopoiesis of indeterminate potential (CHIP) associated clonal hematopoiesis. It aims to enhance our comprehension of this multifaceted association, offering insights into potential avenues for future research and therapeutic interventions.

RECENT FINDINGS

Recent insights reveal that mutations in CHIP-associated genes are not limited to symptomatic patients but are also present in asymptomatic individuals. This section focuses on the impact of obesity-induced inflammation and fatty bone marrow (FBM) on the development of CHIP-associated diseases. Common comorbidities such as obesity, diabetes, and infection, fostering pro-inflammatory environments, play a pivotal role in the acceleration of these pathologies. Our research underscores a notable association between CHIP and an increased waist-to-hip ratio (WHR), emphasizing the link between obesity and myeloid leukemia. Recent studies highlight a strong correlation between obesity and myeloid leukemias in both children and adults, with increased risks and poorer survival outcomes in overweight individuals.

SUMMARY

We discuss recent insights into how CHIP-associated pathologies respond to obesity-induced inflammation, offering implications for future studies in the intricate field of clonal hematopoiesis.

Obesity-induced inflammation exacerbates clonal hematopoiesis

Characterized by the accumulation of somatic mutations in blood cell lineages, clonal hematopoiesis of indeterminate potential (CHIP) is frequent in aging and involves the expansion of mutated hematopoietic stem and progenitor cells (HSC/Ps) that leads to an increased risk of hematologic malignancy. However, the risk factors that contribute to CHIP-associated clonal hematopoiesis (CH) are poorly understood. Obesity induces a proinflammatory state and fatty bone marrow (FBM), which may influence CHIP-associated pathologies. We analyzed exome sequencing and clinical data for 47,466 individuals with validated CHIP in the UK Biobank. CHIP was present in 5.8% of the study population and was associated with a significant increase in the waist-to-hip ratio (WHR). Mouse models of obesity and CHIP driven by heterozygosity of Tet2, Dnmt3a, Asxl1, and Jak2 resulted in exacerbated expansion of mutant HSC/Ps due in part to excessive inflammation. Our results show that obesity is highly associated with CHIP and that a proinflammatory state could potentiate the progression of CHIP to more significant hematologic neoplasia. The calcium channel blockers nifedipine and SKF-96365, either alone or in combination with metformin, MCC950, or anakinra (IL-1 receptor antagonist), suppressed the growth of mutant CHIP cells and partially restored normal hematopoiesis. Targeting CHIP-mutant cells with these drugs could be a potential therapeutic approach to treat CH and its associated abnormalities in individuals with obesity.

Differential Survival Outcomes Between De Novo and Secondary Acute Promyelocytic Leukemia: An Updated Population-based study

BACKGROUND

Whether the characteristics and outcome of secondary acute promyelocytic leukemia (s-APL) are similar to de no APL (dn-APL) remains unknown.

PATIENTS AND METHODS

Using the SEER database, we identified 3877 patients with APL diagnosed from 2000 to 2014, including 465 s-APL and 3412 dn-APL.

RESULTS

Compared with dn-APL, s-APL werecharacterized by older median age, and a higher early mortality rate. Multivariate Cox model showed s-APL, older age, earlier year of diagnosis, and male gender were independently associated with worse survival. Notably, s-APL had a significantly inferior survival regardless of gender, race, marital status, and year of diagnosis. However, the difference between the 2 cohorts was only evident in younger patients (≤ 65 years) but was lost in older patients (> 65 years). Additionally, the majority of index cancer type was breast and prostate in female and male s-APL, respectively. Latency < 3 years was associated with superior survival in s-APL with breast index cancer.

CONCLUSIONS

Inferior survival of s-APL points to the need for treatment improvement.

Comanagement Strategy Between Academic Institutions and Community Practices to Reduce Induction Mortality in Acute Promyelocytic Leukemia

Acute promyelocytic leukemia (APL) is a curable leukemia with > 90% survival in clinical trials. Population-based studies from Sweden and US SEER data have shown long-term survival rates of 62% and 65.7%, with the lower rate being from a higher percentage of early deaths.

Therapy-related acute promyelocytic leukemia with FMS-like tyrosine kinase 3-internal tandem duplication mutation in solitary bone plasmacytoma: A case report

BACKGROUND

Therapy-related acute promyelocytic leukemia (t-APL) is a rare complication observed in solitary bone plasmacytoma (SBP), and SBP after radiotherapy evolving to APL harboring the FMS-like tyrosine kinase 3-internal tandem duplication (FLT3-ITD) mutation has never been reported. Here, we present the first case reported until now.

CASE SUMMARY

We describe a 64-year-old woman who presented with lumbar pain and was initially diagnosed with SBP. However, after one year of radiotherapy treatment, this patient experienced a long-standing bone-marrow-suppressive period and finally developed APL harboring the FLT3-ITD mutation, as confirmed by analyses of clinical features, bone marrow morphology, flow cytometry, cytogenetic examination, and molecular biology. On admission, the patient had disseminated intravascular coagulation and intracranial hemorrhage, and the peripheral blood and bone marrow smear displayed abundant abnormal promyelocytes. Unfortunately, she died when the definite diagnosis was made.

CONCLUSION

The patient with t-APL harboring FLT3-ITD mutation evolving from SBP after radiotherapy had not been reported and had poor clinical outcomes. FLT3-ITD mutation in t-APL may be a potential pathogenesis of leukemogenesis. We should consider the potential risk of secondary neoplasms in SBP patients after radiotherapy.

Oral arsenic trioxide, all-trans retinoic acid, and ascorbic acid maintenance after first complete remission in acute promyelocytic leukemia: Long-term results and unique prognostic indicators

BACKGROUND

The role of arsenic trioxide (As₂ O₃ ) in the maintenance of first complete remission (CR1) in acute promyelocytic leukemia (APL) is unclear.

METHODS

A total of 129 consecutive adult patients with APL of all risk categories who achieved CR1 with conventional induction (all-trans retinoic acid [ATRA]/daunorubicin) and consolidation (daunorubicin/cytarabine [induction daunorubicin and consolidation omitted for age ≥70 years]) underwent maintenance comprising ATRA (45 mg/m² /day), oral As₂ O₃ (10 mg/day), and ascorbic acid (1 g/day) (AAA) for 2 weeks every 2 months for 2 years.

RESULTS

Over a 17-year period from August 1, 2002, to July 31, 2019, 63 men and 66 women (median age, 46 years [range, 18-82 years]) received AAA maintenance, which was already completed in 117 patients. At a median follow-up of 100 months (range, 8-215 months), 17 patients (13%) developed first relapse (R1) (hematologic, n = 14; molecular, n = 3) after a median of 19 months (range, 7-96 months) from CR1. Two R1 patients had concomitant central nervous system (CNS) involvement. All patients achieved CR2 with oral As₂ O₃ -based salvage. Five patients had a subsequent relapse and died. Eight patients died of unrelated causes while still in CR1. The 5-year and 10-year rates of relapse-free survival (RFS) were 89% and 85%, respectively. The 5-year and 10-year rates of overall survival (OS) were 94% and 87%, respectively. Multivariate analysis showed that inferior RFS was associated with FLT3-ITD (P = .005) and CNS involvement on presentation (P = .004), and inferior OS was associated with therapy-related APL (P = .03), FLT3-ITD (P = .03), and relapse (P = .03). The safety profile was favorable, with no grade 3/4 organ toxicities.

CONCLUSION

CR1 maintenance with AAA is safe and results in favorable long-term survival in patients with APL.

Clinicopathological aspects of therapy-related acute myeloid leukemia and myelodysplastic syndrome

Therapy-related myeloid neoplasm (t-MN) is a rare but devastating consequence of chemotherapy and/or radiotherapy used for the treatment of solid cancers and various hematologic malignancies. Our current understanding of the etiology is that hematopoietic clones that are contemporaneous with the primary cancer and resistant to the cytotoxic exposure have the potential to undergo selective expansion and transformation to t-MN. Consequently, a large proportion of cases are associated with adverse risk factors, resulting in limited effective treatment options. Despite the emergence of some therapies with promising activity in t-MN, most effects are short-lived and allogeneic stem cell transplantation remains the only curative option for eligible patients. This review summarizes the current literature on t-AML and t-MDS, with the aim of providing practical recommendations on the clinical evaluation and management of these conditions.

Identification of the novel deletion-type PML-RARA mutation associated with the retinoic acid resistance in acute promyelocytic leukemia

All-trans retinoic acid (ATRA) and arsenic trioxide (ATO) are essential for acute promyelocytic leukemia (APL) treatment. It has been reported that mutations in PML-RARA confer resistance to ATRA and ATO, and are associated with poor prognosis. Although most PML-RARA mutations were point mutations, we identified a novel seven amino acid deletion mutation (p.K227_T233del) in the RARA region of PML-RARA in a refractory APL patient. Here, we analyzed the evolution of the mutated clone and demonstrated the resistance of the mutated clone to retinoic acid (RA). Mutation analysis of PML-RARA was performed using samples from a chemotherapy- and ATRA-resistant APL patient, and the frequencies of mutated PML-RARA transcript were analyzed by targeted deep sequencing. To clarify the biological significance of the identified PML-RARA mutations, we analyzed the ATRA-induced differentiation and PML nuclear body formation in mutant PML-RARA-transduced HL-60 cells. At molecular relapse, the p.K227_T233del deletion and the p.R217S point-mutation in the RARA region of PML-RARA were identified, and their frequencies increased after re-induction therapy with another type of retinoiec acid (RA), tamibarotene. In deletion PML-RARA-transduced cells, the CD11b expression levels and NBT reducing ability were significantly decreased compared with control cells and the formation of PML nuclear bodies was rarely observed after RA treatment. These results indicate that this deletion mutation was closely associated with the disease progression during RA treatment.

Characteristics and outcome of patients with therapy-related acute promyelocytic leukemia front-line treated with or without arsenic trioxide

Therapy-related acute promyelocytic leukemia (t-APL) is relatively rare, with limited data on outcome after treatment with arsenic trioxide (ATO) compared to standard intensive chemotherapy (CTX). We evaluated 103 adult t-APL patients undergoing treatment with all-trans retinoic acid (ATRA) alone (n=7) or in combination with ATO (n=24), CTX (n=53), or both (n=19). Complete remissions were achieved after induction therapy in 57% with ATRA, 100% with ATO/ATRA, 78% with CTX/ATRA, and 95% with CTX/ATO/ATRA. Early death rates were 43% for ATRA, 0% for ATO/ATRA, 12% for CTX/ATRA and 5% for CTX/ATO/ATRA. Three patients relapsed, two developed therapy-related acute myeloid leukemia and 13 died in remission including seven patients with recurrence of the prior malignancy. Median follow-up for survival was 3.7 years. None of the patients treated with ATRA alone survived beyond one year. Event-free survival was significantly higher after ATO-based therapy (95%, 95% CI, 82-99%) as compared to CTX/ATRA (78%, 95% CI, 64-87%; P=0.042), if deaths due to recurrence of the prior malignancy were censored. The estimated 2-year overall survival in intensively treated patients was 88% (95% CI, 80-93%) without difference according to treatment (P=0.47). ATO when added to ATRA or CTX/ATRA is feasible and leads to better outcomes as compared to CTX/ATRA in t-APL.

Acute myeloid leukemia following etoposide therapy for EBV-associated hemophagocytic lymphohistiocytosis: a case report and a brief review of the literature

Background

Hemophagocytic lymphohistiocytosis (HLH) is a rare, life-threatening disorder characterized by prolonged fever, cytopenia, hepatosplenomegaly, rash, icterus, and other neurological symptoms. Successful treatment of HLH by etoposide has improved outcomes for children with HLH. However, the development of treatment-related acute myeloid leukemia (t-AML) after the usage of this drug is a concern.

Case presentation

We report a case of acquired EBV-triggered HLH with progression to t-AML following etoposide therapy with cytogenetic abnormality for t (11; 19) (q23; p13) resulting in MLL gene fusion. The development of t-AML was detected 23 months after HLH diagnosis.

Conclusions

Although the successful treatment of HLH by etoposide has improved outcomes for children with HLH, t-AML is a serious complication of topoisomerase II inhibitor therapy and is characterized by the presence of gene rearrangement. This study suggests that HLH patients undergoing therapy with HLH-2004 protocol need monitoring for future malignancy, especially in the initial 2 to 3 years.

CD34(+) therapy-related acute promyelocytic leukemia in a patient previously treated for breast cancer

Therapy-related acute myeloid leukemia (AML) is a long term complication of chemotherapy for a variety of cancers. In most cases, the marrow demonstrates high risk cytogenetics and the prognosis is poor. In a minority of patients "good risk" cytogenetics, including t(15;17)(q22;q12), are seen and the patient's prognosis is similar to those who have de novo disease. Currently we present a patient who developed therapy-related acute promyelocytic leukemia (APL) after chemoradiotherapy for breast cancer. This case was especially atypical because the leukemic cells were CD34(+), which is an unusual immunophenotype for APL. Recognition that this patient had APL, rather than the more common therapy-related MDS or AML, was imperative to initiate chemotherapy in a timely manner.

Survival of de novo and secondary acute promyelocytic leukemia: a propensity-matched analysis of the SEER database

Prior studies demonstrated that secondary acute promyelocytic leukemia (sAPL) and de novo APL may but not consistently have similar overall survival (OS). We used the Surveillance, Epidemiology, and End Results (SEER) 13 database to compare their OS. Patients with sAPL (n = 90), compared to de novo APL (n = 1600), were more likely to be older, White and diagnosed after year 2005. Mortality rate at 1 month (28.9% vs. 23.0%, p = 0.20) and 5-year OS (42% vs. 50%, p = 0.24) was similar between sAPL and de novo APL. In a multivariate analysis, sAPL was associated with similar OS as de novo APL (hazard ratio, HR 1.11; 95% confidence interval, CI 0.78-1.58; p = 0.546). This population-based study demonstrated no difference in OS or early mortality rate between sAPL and de novo APL. sAPL can be managed very similarly to de novo APL and does not need to be excluded from clinical trials of APL.

Secondary acute promyelocytic leukemia following chemotherapy for gastric cancer: a case report

Therapy-related acute myeloid leukemia (t-AML) refers to a heterogeneous group of myeloid neoplasms that develop in patients following extensive exposure to either cytotoxic agents or radiation. The development of t-AML has been reported following treatment of cancers ranging from hematological malignancies to solid tumors; however, to our knowledge, t-AML has never been reported following treatment of gastric cancer. In this study, we report the development of t-acute promyelocytic leukemia in a cT4N1M0 gastric cancer patient after an approximate 44 mo latency period following treatment with 4 cycles of oxaliplatin (OXP) (85 mg/m(2) on day 1) plus capecitabine (1250 mg/m(2) orally twice daily on days 1-14) in combination with recombinant human granulocyte-colony stimulating factor treatment. Karyotype analysis of the patient revealed 46,XY,t(15;17)(q22;q21)[15]/46,idem,-9,+add(9)(p22)[2]/46,XY[3], which, according to previous studies, includes some "favorable" genetic abnormalities. The patient was then treated with all-trans retinoic acid (ATRA, 25 mg/m(2)/d) plus arsenic trioxide (ATO, 10 mg/d) and attained complete remission. Our case illuminated the role of certain cytotoxic agents in the induction of t-AML following gastric cancer treatment. We recommend instituting a mandatory additional evaluation for patients undergoing these therapies in the future.

Global characteristics of childhood acute promyelocytic leukemia

Acute promyelocytic leukemia (APL) comprises approximately 5-10% of childhood acute myeloid leukemia (AML) cases in the US. While variation in this percentage among other populations was noted previously, global patterns of childhood APL have not been thoroughly characterized. In this comprehensive review of childhood APL, we examined its geographic pattern and the potential contribution of environmental factors to observed variation. In 142 studies (spanning >60 countries) identified, variation was apparent-de novo APL represented from 2% (Switzerland) to >50% (Nicaragua) of childhood AML in different geographic regions. Because a limited number of previous studies addressed specific environmental exposures that potentially underlie childhood APL development, we gathered 28 childhood cases of therapy-related APL, which exemplified associations between prior exposures to chemotherapeutic drugs/radiation and APL diagnosis. Future population-based studies examining childhood APL patterns and the potential association with specific environmental exposures and other risk factors are needed.

Recent advances in the management of therapy-related myelodysplastic syndromes and acute myeloid leukemia

PURPOSE OF REVIEW

Therapy-related myelodysplastic syndromes and acute myelogenous leukemia (t-MDS/AML) comprise an increasingly common, poor-risk disease cohort without standard treatment options. This review describes available treatments and recent advances that may influence the clinical management of t-MDS/AML.

RECENT FINDINGS

Multiple retrospective studies have identified poor-risk cytogenetics, chemotherapy resistance, comorbidities from prior cancer and therapy, and persistence of the primary malignancy as factors that contribute to poor clinical outcomes of t-MDS/AML. Recent analyses show that t-MDS/AML can respond to standard therapy, but responses are less durable. In most cases, cure is made more likely with allogeneic stem cell transplantation. These findings suggest that improved survival may result from earlier, low-intensity nontransplant therapy, and aggressive pursuit of reduced-intensity transplant approaches in eligible individuals coupled with posttransplant relapse prevention strategies. Molecular characterization of t-MDS/AML may aid future clinical management decisions and identify targets for therapy.

SUMMARY

Data emerging from recent t-MDS/AML studies are shedding light on factors that contribute to disease biology and poor clinical outcomes. These findings can be used to develop strategies to improve the treatment and survival of patients with t-MDS/AML.

Therapy-related acute myeloid leukemia with favorable cytogenetics: still favorable?

Therapy-related acute myeloid leukemia (t-AML) is occasionally associated with favorable risk cytogenetics including core binding factor AML and acute promyelocytic leukemia (APL). It is unclear if these leukemias have the same favorable outcomes as their de novo counterparts. Interpretation of published data is difficult due to lack of data on the contribution of the original neoplasm as well as its treatment to overall mortality. Based on available evidence, we conclude that t-AML with favorable risk cytogenetics have superior outcomes among t-AMLs and should be treated similar to de novo AML in patients who are candidates for definitive therapy. Therapy-related APL has similar outcome as de novo APL. There is no evidence at the present time to support the routine use of allogeneic HSCT in first complete remission in t-AML with favorable cytogenetics.