A basis for updating our approach to resistant acute leukemia

Cardiac Relapse of Acute Lymphoblastic Leukemia Following Hematopoietic Stem Cell Transplantation: A Case Report and Review of Literature

Isolated extramedullary relapse of acute lymphoblastic leukemia (ALL) occurs in soft tissues and various organs outside the testis and central nervous system. Treatments such as hematopoietic stem cell transplantation and more novel modalities such as immunotherapy have eradicated ALL at extramedullary sites. In some instances, survival times for relapsed ALL at these sites are longer than those for relapsed disease involving only the bone marrow. Isolated relapse of ALL in the myocardium is rare, especially in children, making diagnosis and treatment of it difficult. More recent treatment options such as chimeric antigen receptor T-cell therapy carry a high risk of cytokine release syndrome and associated risk of worsening cardiac function. Herein we present the case of an 11-year-old boy who presented with relapsed symptomatic B-cell ALL in the myocardium following allogeneic hematopoietic stem cell transplantation. This is an unusual presentation of relapsed ALL and this case demonstrates the associated challenges in its diagnosis and treatment. The case report is followed by a literature review of the advances in treatment of pediatric leukemia and their application to extramedullary relapse of this disease in particular.

Single organ microenvironment and the common features of tumors of leukemia, lymphoma, and myeloma cells growing there: A literature review

OBJECTIVE

To explore whether the growth and treatment resistance of lymphoma and myeloma tumors is similar to that previously observed in leukemic and solid tumors growing in the same organ microenvironment.

METHODS

All published cases of 3 primary hematologic malignancies in breast, without systemic involvement, were identified, with follow-ups solicited from authors. Treatment approaches were analyzed to highlight the most effective.

RESULTS

Similar histologic features and biology among primary tumors of leukemia, lymphoma, plasmacytoma, and solid breast cancer was revealed. Review of treatments: tumor-directed, chemotherapy, or combination showed the benefit of tumor removal, and use of systemic agents in adjunct, not primary, treatment. Optimal assessment is limited by few cases of PET/CT verifying limited tumor extent. The common biology observed and cases of long survival after tumor/stroma eradication point to the complicity of organ microenvironment in the chemoresistance and treatment failure commonly observed in patients.

CONCLUSIONS

The interaction of an organ microenvironment, particularly its adipocytes, with malignant cells, results in similar histologic changes, metastatic potential, and chemoresistance in 3 hematologic malignancies and solid cancers. Improved survival in hematologic malignancies could result from adopting PET/CT to find tumor and its extent, eradicating tumor, and elucidating common therapeutic targets.

The myeloid sarcoma treated by Venetoclax with hypomethylating agent followed by stem cell transplantation: rare case report

BACKGROUND

Myeloid sarcoma (MS) is a very rare condition, develops both in patients with other hematological neoplasms, and as isolated tumor. MS of the gynecologic tract is extremely rare. An available literature data about diagnosis and management of MS is summarized in the article. The role of chemotherapy, radiation therapy, surgery and bone marrow transplantation in the treatment is discussed. Polychemotherapy and allogeneic bone marrow transplantation were suggested to be the optimal treatment strategy of MS of the gynecological tract. The use of new targeted agents results in promising clinical data.

CASE PRESENTATION

We are presenting a rare clinical case of a MS of the uterine cervix with concomitant bone marrow involvement and describe all the peculiarities of the clinical course, diagnosis, and treatment. The patient received chemotherapy followed by allogeneic bone marrow transplantation. The pre-transplant therapy allowed us to perform allogeneic bone marrow transplantation with the deepest response possible: complete PET-negative and MRD-negative remission of the disease.

CONCLUSIONS

MS remains a subject of discussion regarding its diagnostic and therapeutic aspects. The use of novel targeting agents can be perspective option for patient with extramedullary disease.

Post-transplant leukemia relapse in organs: biology. and behavior in 585 reports

Resistance of extramedullary leukemia growth post-transplant prevents cure. Review of its behavior detailed in 585 published cases should lead to better treatment. Leukemic tumors were found up to 13 years after transplant, most in sites inaccessible to physical exam. In 83%, marrow was not in morphologic relapse; next relapse was most often extramedullary. Induction protocols alone produced few durable responses in acute leukemias and fatal marrow aplasia in 17 %. Overall, 120 patients survived over 2 years, 43 relapse-free up to 18 years, the majority after combined tumor-directed and systemic therapy. Overall median survival was 9 months. This review highlights how results can improve: by defining extent of leukemia involvement with scans before transplant, and emergently when leukemic tumor is found after, ablating tumor directly to abort metastasis, and determining dosing of systemic chemotherapy that protects, without ablating, donor marrow. Monitoring total body remission with body scans should increase transplant cures.

Extramedullary leukemia behaving as solid cancer: clinical, histologic, and genetic clues to chemoresistance in organ sites

Recent studies of leukemic tumors in individual extramedullary sites showed they adopt the clinical and metastatic behavior of solid cancers originating in those sites. To elucidate features of leukemic tumors that render them resistant to agents effective against marrow leukemia, we analyzed a series of AML breast tumors by histology, immunohistochemistry, and RNA sequencing. Striking histologic similarities to solid cancers were found: a single-filing architectural pattern virtually identical to that of invasive lobular breast carcinoma and dense desmoplastic keloid-like fibrosis similar to colon, gallbladder, and pancreas carcinomas. Sequencing found 2157 genes significantly downregulated in AML breast tumors compared to normal breast. Comparison to triple-negative breast cancer found 859 genes similarly downregulated. At least 30 of these genes have been associated with poor prognosis in breast cancers. Five were reported in AML marrow studies to correlate with poor prognosis. The findings of this pilot study suggest the seed-and-soil interaction recognized in solid cancer growth may help explain how leukemic cells, in some patients, adopt solid tumor behavior in non-marrow sites. Transformed cells that metastasize from tumor to marrow can impart chemoresistance and be an unrecognized cause of treatment failure and death. Further studies comparing leukemic tumor to simultaneous marrow could potentially identify biomarkers that predict extramedullary resistance and lead to new therapeutic targets. Recognizing the potential for leukemia to adopt solid tumor phenotype, and implementation of body scanning and ablative tumor treatment, could decrease the persistently high rates of marrow resistance and treatment failure.

Mechanisms of extramedullary relapse in acute lymphoblastic leukemia: Reconciling biological concepts and clinical issues

Long-term survival rates in childhood acute lymphoblastic leukemia (ALL) are currently above 85% due to huge improvements in treatment. However, 15-20% of children still experience relapses. Relapses can either occur in the bone marrow or at extramedullary sites, such as gonads or the central nervous system (CNS), formerly referred to as ALL-blast sanctuaries. The reason why ALL cells migrate to and stay in these sites is still unclear. In this review, we have attempted to assemble the evidence concerning the microenvironmental factors that could explain why ALL cells reside in such sites. We present criteria that make extramedullary leukemia niches and solid tumor metastatic niches comparable. Indeed, considering extramedullary leukemias as metastases could be a useful approach for proposing more effective treatments. In this context, we conclude with several examples of potential niche-based therapies which could be successfully added to current treatments of ALL.

Leukemia in gastrointestinal organs as cause of treatment failure: 378 cases analyzed

Leukemia growing as tumors in gastrointestinal organs is an under-investigated cause of treatment failure and death. These present with symptoms often mistaken for common toxicities but may grow large before symptoms. To synthesize experience available only in case reports, 378 were analyzed. Invasive and metastatic behavior typical of solid GI tumors was revealed even when marrow was uninvolved. Within 3 months of diagnosis, 33% had died, 47% within 1 year. Survivals of 4 to 18 years after involvement suggest cure is possible. Evidence is presented that combined local and systemic therapy has successfully treated GI leukemic tumors when identified early.

18 FDG-PET/CT: 21st century approach to leukemic tumors in 124 cases

Extramedullary tumors remain an obstacle to curing more acute leukemia patients. Their incidence is unknown because the presence of occult tumors that contribute to relapse is not routinely sought as in other cancers. No standard approach exists for treating tumors at most sites, apparent clinical response is typically followed by further tumors, and achievement of lengthy remission is uncommon. Body scanning with (18) FDG PET/CT now provides a means to identify the extent of occult tumors that enables directed tumor eradication and a way to evaluate tumor response. To evaluate its potential benefits, analysis was undertaken of 124 published cases scanned after apparent tumors were diagnosed. Clinical and radiologic exams underestimated extent of disease in over half of 100 cases. Among 70 cases that reported scans after various treatments, 70% achieved negative scans. Half relapsed subsequently but disease-free survivals up to 6 years were documented. These reported cases add to our knowledge of extramedullary leukemia in showing that further tumors are more likely than marrow relapse, clinical and radiologic evaluation of response is inadequate, intensive chemotherapy alone generally does not prevent progression and is associated with significant mortality, and tumor-directed plus systemic therapies appears the most effective approach, particularly to AML tumors. This analysis suggests this technology could increase our ability to eradicate all foci of leukemia, and identify tumors responsible for refractory, residual, and relapsed disease.

Acquired resistance of leukemic cells to AraC is associated with the upregulation of aldehyde dehydrogenase 1 family member A2

The elucidation of drug resistance mechanisms is important in the development of clinical therapies for the treatment of leukemia. To study the drug resistance mechanisms, protein expression profiles of 1-β-D-arabinofuranosylcytosine (AraC)-sensitive K562 (K562S) cells and AraC-resistant K562 (K562AC) cells were compared using two-dimensional fluorescence difference gel electrophoresis. In a comparison of protein expression profiles, 2073 protein spots were found to be altered, and 15 proteins of them were remarkably altered. These proteins were identified by mass spectrometry. The most differently expressed proteins were aldehyde dehydrogenase 1 family member A2 (ALDH1A2) and vimentin. Both proteins were verified using reverse transcriptase polymerase chain reaction and Western blot analysis. ALDH1A2 protein was found to be effective in AraC resistance. ALDH1A2 knock-down induced sensitivity to AraC treatment in K562AC cells, and ALDH1A2 overexpressed K562S cells acquired the AraC resistance. Furthermore, the findings also suggest that ALDH1A2 expression is increased after the appearance of AraC resistance in clinical cases. These results will be helpful in understanding the mechanism of AraC resistance.

Is acute myeloid leukemia a liquid tumor?

Extramedullary manifestations of acute myeloid leukemia (AML) were described as early as the 19th century. However, the incidence, clinical significance and pathobiology of extramedullary AML remain ill defined. We reviewed case reports, retrospective case series, pilot studies and imaging studies of extramedullary leukemia (EML) to determine its frequency, characteristics, clinical presentation and significance. EML precedes or accompanies development of AML and occurs during or following treatment, even during remission. Although imaging studies are rarely conducted and the true incidence of EML has yet to be verified, authors have reported several estimates based on retrospective and autopsy studies. The incidence of EML in patients with AML of all ages is estimated to be about 9% and EML in children with AML was detected in 40% of patients at diagnosis. The combination of positron emission tomography and computed tomography were the most sensitive and reliable techniques of detecting and monitoring EML. Based on our literature review, the frequency of EML is likely underreported. The well-documented nature of EML in patients with AML suggests that AML can manifest as a solid tumor. The extent to which EML accompanies AML and whether EML is derived from bone marrow are unknown. Furthermore, questions remain regarding the role of the microenvironment, which may or may not facilitate the survival and proliferation of EML, and the implications of these interactions with regard to minimal residual disease, tumor cell quiescence and relapse. Therefore, prospective studies of detection and characterization of EML in patients with AML are warranted.