Myeloid differentiation antigen and cytokine receptor expression on acute myelocytic leukaemia cells with t(16;21)(p11;q22): frequent expression of CD56 and interleukin-2 receptor alpha chain

Acute myeloid leukemia with rare recurring translocations-an overview of the entities included in the international consensus classification

Two different systems exist for subclassification of acute myeloid leukemia (AML); the World Health Organization (WHO) Classification and the International Consensus Classification (ICC) of myeloid malignancies. The two systems differ in their classification of AML defined by recurrent chromosomal abnormalities. One difference is that the ICC classification defines an AML subset that includes 12 different genetic abnormalities that occur in less than 4% of AML patients. These subtypes exhibit distinct clinical traits and are associated with treatment outcomes, but detailed description of these entities is not easily available and is not described in detail even in the ICC. We searched in the PubMed database to identify scientific publications describing AML patients with the recurrent chromosomal abnormalities/translocations included in this ICC defined patient subset. This patient subset includes AML with t(1;3)(p36.3;q21.3), t(3;5)(q25.3;q35.1), t(8;16)(p11.2;p13.3), t(1;22)(p13.3;q13.1), t(5;11)(q35.2;p15.4), t(11;12)(p15.4;p13.3) (involving NUP98), translocation involving NUP98 and other partner, t(7;12)(q36.3;p13.2), t(10;11)(p12.3;q14.2), t(16;21)(p11.2;q22.2), inv(16)(p13.3q24.3) and t(16;21)(q24.3;q22.1). In this updated review we describe the available information with regard to frequency, biological functions of the involved genes and the fusion proteins, morphology/immunophenotype, required diagnostic procedures, clinical characteristics (including age distribution) and prognostic impact for each of these 12 genetic abnormalities.

Donor-Derived CD123-Targeted CAR T Cell Serves as a RIC Regimen for Haploidentical Transplantation in a Patient With FUS-ERG+ AML

Background: Allogeneic hematopoietic stem cell transplantation (allo-HSCT) following chemotherapy is part of standard treatment protocol for patients with acute myeloid leukemia (AML). FUS-ERG+ AML is rare but has an extremely poor prognosis even with allo-HSCT in remission, possibly due to its a leukemia stem cell (LSC)-driven disease resulting in chemotherapy resistance and a novel therapy is urgently required. It has been reported that FUS-ERG-positive AML expresses CD123, a marker of LSC, in some cases. CD123-targeted CAR T cell (CART123) is promising immunotherapy, but how to improve the complete remission (CR) rate and rescue potential hematopoietic toxicity still need to explore.

Case Presentation: We used donor-derived CART123 as part of conditioning regimen for haploidentical HSCT (haplo-HSCT) in a patient with FUS-ERG+ AML who relapsed after allogeneic transplantation within 3 months, resists to multi-agent chemotherapy and donor lymphocyte infusion (DLI) and remained non-remission, aiming to reduce these chemotherapy-resistant blasts and rescue potential hematopoietic toxicity. The blasts in BM were reduced within 2 weeks and coincided with CAR copies expansion after CART123 infusion. The patient achieved full donor chimerism, CR with incomplete blood count recovery, and myeloid implantation.

Conclusion: Our results hints that CART123 reduces the chemotherapy-resistant AML blasts for FUS-ERG+ AML without affecting the full donor chimerism and myeloid implantation.

Hemophagocytosis by Leukemic Blasts in T Cell Acute Lymphoblastic Leukemia: An Unusual Finding

Hemophagocytosis shows engulfment of hematopoietic cells by histiocytes and is a property generally associated with cells of the histiocytic lineage. It can be familial or is seen in a wide spectrum of acquired disorders. Hemophagocytosis by leukemic blasts is an uncommon phenomenon and has been reported mainly in acute myeloid leukemia. Its association with acute lymphoblastic leukemia is rare. We present a case of hemophagocytosis by blasts in the bone marrow in a 11 year old boy with T cell-acute lymphoblastic leukemia.

[Clinical characteristics of acute myeloid leukemia with t (16;21) (p11;q22):nine cases report and literature review]

OBJECTIVE

To analyze the biological and clinical characteristics of acute myeloid leukemia (AML) with t (16;21) (p11;q22), and the curative effect and prognosis.

METHODS

A retrospective study was conducted in nine cases with AML with t(16;21) (p11;q22) from January, 2009 to December, 2014 in People's Hospital of Peking University.

RESULTS

Of 1 372 AML patients, 9 cases with t(16;21) (p11;q22), 4 males and 5 females, were identified. According to the FAB classification, 1 case was classified as M1, 5 as M2, 1 as M4, 2 as M5. Three patients have morphological cavity at the time of diagnosis. Immunophenotypic features showed the positive CD117, CD13, CD33 and CD34, especially CD56. 5 cases were identified as complex karyotype abnormalities, besides from t (16;21) (p11;q22). All cases could be detected TLS/FUS-ERG fusion genes. 9 cases acquired complete remission (CR) after chemotherapy. 2 cases were only treated with chemotherapy and relapsed after 5 months and 16 months, and died at 10 months and 27 months after diagnosis. 7 of 9 cases accepted allogeneic hematopoietic stem cell transplantation (allo-HSCT) after chemotherapy, the median survival for 21 months (11-46 months). Summarized the 42 cases of adult AML with t (16;21) (p11;q22) from literature, 27 cases with chemotherapy alone, 15 cases underwent HSCT, the median survival for 10 (95% CI 1-17) months and 18(95% CI 2-76) months, respectively. The difference was statistically significant (P<0.001).

CONCLUSIONS

AML with t (16;21) (p11;q22) was rare, it has a special form and distinct immunophenotypic characteristics and poor prognosis, allo-HSCT could improve the prognosis and should be considered after CR.

The oncofusion protein FUS-ERG targets key hematopoietic regulators and modulates the all-trans retinoic acid signaling pathway in t(16;21) acute myeloid leukemia

The ETS transcription factor ERG has been implicated as a major regulator of both normal and aberrant hematopoiesis. In acute myeloid leukemias harboring t(16;21), ERG function is deregulated due to a fusion with FUS/TLS resulting in the expression of a FUS–ERG oncofusion protein. How this oncofusion protein deregulates the normal ERG transcription program is unclear. Here, we show that FUS–ERG acts in the context of a heptad of proteins (ERG, FLI1, GATA2, LYL1, LMO2, RUNX1 and TAL1) central to proper expression of genes involved in maintaining a stem cell hematopoietic phenotype. Moreover, in t(16;21) FUS–ERG co-occupies genomic regions bound by the nuclear receptor heterodimer RXR:RARA inhibiting target gene expression and interfering with hematopoietic differentiation. All-trans retinoic acid treatment of t(16;21) cells as well as FUS–ERG knockdown alleviate the myeloid-differentiation block. Together, the results suggest that FUS–ERG acts as a transcriptional repressor of the retinoic acid signaling pathway.

Establishment and characterization of a novel acute myeloid leukemia cell line, JIH-4, carrying a t(16;21)(p11.2;q22) and expressing the FUS-ERG fusion

Human leukemia cell lines are powerful tools in the study of leukemogenesis, particularly for rare but recurrent subtypes such as acute myeloid leukemia (AML) with the t(16;21)(p11.2;q22) and FUS-ERG fusion. Four AML cell lines carrying a t(16;21)(p11.2;q22) have been described previously. We report a novel AML cell line, designated JIH-4, for which karyotypic analysis demonstrated a single abnormality, t(16;21)(p11.2;q22). The FUS-ERG fusion transcript was identified by reverse transcriptase polymerase chain reaction (RT-PCR). Neither Epstein-Barr virus nor mycoplasma was detected in JIH-4 cells. The morphology and immunoprofile of JIH-4 cells display typical features of myelogenous lineage, and short tandem-repeat PCR comparison with the donor patient's bone marrow cells confirm the cell line's authenticity. Tumor masses were found in 50% of inoculated mice 83 days after subcutaneous injection with JIH-4 cells. Our results confirm that JIH-4 cells are derived from the donor patient's leukemia cells and support using the JIH-4 cell line as a valuable tool in the study of leukemogenesis.

Clinical and prognostic significance of cytokine receptor expression in adult acute lymphoblastic leukemia: interleukin-2 receptor α-chain predicts a poor prognosis

We quantitatively assessed the expression of cytokine receptors (interleukin-2 receptor (IL-2R), IL-3R, IL-4R, IL-5R, IL-6R, IL-7R, granulocyte-macrophage colony-stimulating factor R (GM-CSFR), G-CSFR, c-fms, c-mpl, c-kit and FLT3) in cells from 211 adults with acute lymphoblastic leukemia (ALL) by flow cytometry and determined their prevalence and clinical significance. Although all cytokine receptors were expressed to various degrees, the levels of IL-3R alpha-chain (IL-3Ralpha), IL-2Ralpha, IL-2Rbeta, IL-7Ralpha, common-Rgamma(gammac), c-mpl, c-kit and FLT3 exhibited a wide spectrum > or =2000 sites/cell. Among them, IL-3Ralpha, IL-2Ralpha and FLT3 were highly expressed in B-lineage ALL, whereas IL-7Ralpha, gammac and c-kit predominated in T-lineage ALL. Higher levels of IL-3Ralpha, IL-2Ralpha, c-kit and FLT3 correlated with the expression of CD13/33. Increased IL-2Ralpha levels related to the presence of Philadelphia chromosome (Ph), leukocytosis and shorter event-free survival (EFS). C-kit preferred in male. Elevated FLT3 levels correlated with age > or =60 years. Multivariate analysis in B-lineage ALL revealed only IL-2Ralpha (P=0.028) and Ph (P=0.020) as independent factors for EFS. These findings suggest that several cytokine receptors associated with certain cellular and clinical features, but IL-2Ralpha solely had a prognostic value and should be considered as a major prognostic factor for adult ALL that is comparable with Ph.

Interpretation of interleukin-2 receptor alpha positive cells during induction chemotherapy for adult acute myelogenous leukaemia patients

To correlate clinical outcomes with the expression of interleukin-2 receptor alpha (CD25) positive cells during induction chemotherapy (IC) in adult patients with acute myeloid leukaemia (AML), we investigated the prognostic importance of subsets of peripheral blood (PB) CD45+CD25+ cells. Seventy-five patients with newly diagnosed AML received the same initial IC; and serial PB samples were taken. The gated CD45/CD25 cell populations were used to compare the intensity of immunophenotypic signals based on the treatment timeline. Patients who responded poorly to IC demonstrated exceptionally higher levels of PB CD45+CD25+ cells by percentage (p = 0.003) or by absolute count (p = 0.046) on the seventh day (D + 7) of initial IC. In addition, patients in complete remission (CR) (n = 61) demonstrated relatively lower levels of steady PB CD45+CD25+ after standard IC. These results suggest that the expression of CD25 can be used to predict the response to IC during an early period of treatment.