Characteristics and outcomes of acute myeloid leukaemia patients with baseline CD7 expression.

Targeted therapy development for acute myeloid leukaemia (AML) requires an understanding of specific expression profiles. We collected flow cytometry data on 901 AML patients and recorded aberrant CD7 expression on leukaemic blasts. 263 (29.2%) had blasts positive for CD7. CD7+ AML was more likely to be adverse risk (64.6% vs. 55.6%, p = 0.0074) and less likely to be favourable risk (15.2% vs. 24.1%, p = 0.0074) by European LeukemiaNet 2022 criteria. Overall survival was inferior (11.9 [95% CI, 9.7-15.9] vs. 19.0 months [95% CI, 16.1-23.0], p = 0.0174). At relapse, 30.4% lost and 19.0% gained CD7, suggesting moderate instability over time.

[The Distribution and Significance of Activated T Cells and Lymphocyte Subsets in Myelodysplastic Syndrome].

OBJECTIVE: To investigate the distribution of bone marrow lymphocyte subsets in patients with myelodysplastic syndrome(MDS),the proportion of activated T cells with immunophenotype CD3+HLA-DR+ in the lymphocytes and its clinical significance, and to understand the effects of different types of MDS, different immunophenotypes, and different expression levels of WT1 on the proportion of lymphocyte subsets and activated T cells. METHODS: The immunophenotypes of 96 MDS patients, the subsets of bone marrow lymphocytes and activated T cells were detected by flow cytometry. The relative expression of WT1 was detected by real-time fluorescent quantitative PCR, and the first induced remission rate (CR1) was calculated, the differences of lymphocyte subsets and activated T cells in MDS patients with different immunophenotype, different WT1 expression, and different course of disease were analyzed. RESULTS: The percentage of CD4+T lymphocyte in MDS-EB-2, IPSS high-risk, CD34+ cells >10%, and patients with CD34+CD7+ cell population and WT1 gene overexpression at intial diagnosis decreased significantly (P<0.05), and the percentage of NK cells and activated T cells increased significantly (P<0.05), but there was no significant difference in the ratio of B lymphocytes. Compared with the normal control group, the percentage of NK cells and activated T cells in IPSS-intermediate-2 group was significantly higher(P<0.05), but there was no significant difference in the percentage of CD3+T, CD4+T lymphocytes. The percentage of CD4+T cells in patients with complete remission after the first chemotherapy was significantly higher than in patients with incomplete remission(P<0.05), and the percentage of NK cells and activated T cells was significantly lower than that in patients with incomplete remission (P<0.05). CONCLUSION: In MDS patients, the proportion of CD3+T and CD4+T lymphocytes decreased, and the proportion of activated T cells increased, indicating that the differentiation type of MDS is more primitive and the prognosis is worse.

Association of lymphocyte subsets with mortality in severe COVID-19 pneumonia patients.

BACKGROUND: Few studies have investigated the alterations in the T and B cell counts and related subgroups in pulmonary infections especially COVID-19. Here, we aimed to evaluate total T and B lymphocytes and T cell subgroup counts to find the possible correlation between number of these cells and severity and mortality in COVID-19 patients. METHODS: This study was performed on 40 patients with severe COVID-19 infection confirmed by reverse transcription-polymerase chain reaction (RT-PCR) and chest HRCT in August 2020. By the time of admission, T lymphocytes profile in peripheral blood was investigated using multicolor flow cytometry. The total number of T lymphocytes, CD4+ T cells, CD8+ T cells, and B lymphocytes were calculated. Expression of CD2, CD3, CD5, and CD7 as pan T cell surface markers and expression of CD38 and HLA-DR as activated markers on T lymphocytes were also evaluated. RESULTS: Nine patients (22.5%) died during the study and 16 patients (40%) were admitted to ICU. Deceased patients demonstrated lower amounts of T cell count and CD4+ T cell count (with a marginal difference (p = 0.07)) compared with survived patients at the time of admission. The chance of mortality was significantly higher for patients with CD7 loss (OR = 14.89). A marginally significant relationship was also indicated between CD4<200/ml and mortality (OR = 8.65), but no other significant relationships were observed between variables and ICU admission. CONCLUSION: Altogether, CD7 loss on T lymphocytes and CD4+ T cell count below 200/ml revealed a significant relationship with mortality. Considering T lymphocytes and T cell subgroup count could have a predictive value for patients suffering from COVID-19.

CD2 and CD7 are sensitive flow cytometry screening markers for T-lineage acute leukemia(s): a study of 465 acute leukemia cases.

T-lymphoblastic leukemia/lymphoma (T-ALL/LBL) is a rare acute leukemia that expresses cytoplasmic CD3 (cCD3) and frequently lacks surface CD3. Given that routine flow cytometric testing for cCD3 may not be feasible and cCD3 interpretation may be difficult, we investigate if surface CD2 and/or CD7 expression on blasts can be used by flow cytometry to screen for T-lineage acute leukemia. We retrospectively reviewed flow cytometric data from 233 acute leukemias (36 T-ALL/LBL, 8 mixed-phenotype acute leukemia T/myeloid, 80 acute myeloid leukemia, 97 B-ALL/LBL, 8 mixed-phenotype acute leukemia B/myeloid, and 4 acute undifferentiated leukemia cases). Uniform expression (≥75% of blasts) of CD2 and/or CD7 was seen in all 44 cCD3-positive cases but in only 11% (20/189) of cCD3-negative acute leukemias, thus demonstrating 100% sensitivity and 89% specificity in the identification of cCD3-positive (T-lineage) acute leukemia. To avoid selection bias, we prospectively studied 232 consecutive acute leukemias for which cCD3, CD2, and CD7 were automatically performed in all cases. Similar to the retrospective study, uniform expression of CD2 and/or CD7 on blasts showed 100% sensitivity and 88% specificity in the screening for cCD3-positive (T-lineage) acute leukemia. Therefore, acute leukemias with uniform expression of CD2 and/or CD7 warrant further testing for cCD3 to evaluate for T-lineage acute leukemia. Blasts that lack both uniform CD2 and CD7 expression do not require additional cCD3 testing. We propose that CD2 and CD7 could be utilized in a limited antibody flow cytometry panel as a sensitive, robust, and cost-effective way to screen for T-lineage acute leukemia.

Quantification of T cell clonality in human T cell leukaemia virus type-1 carriers can detect the development of adult T cell leukaemia early.

Adult T cell leukaemia/lymphoma (ATL) arises from clonally expanded T cells that are infected with human T cell leukaemia virus type-1 (HTLV-1). Here, we show that ATL can be detected early in HTLV-1-carriers through quantification of T-cell receptor (TCR)Vß subunit diversity on T-cells infected with HTLV-1 (CD3+ CCR4+ CD26- T-cells) using an 'oligoclonality index' (OCI-flow). We established a reference range for OCI-flow by analysing peripheral blood mononuclear cells (PBMCs) from HTLV-1-carriers who had not developed ATL in a median of 10.5 years follow up (n = 38) and patients with ATL (n = 30). In the third cohort of HTLV-1-carriers with no history or clinical evidence of ATL (n = 106), 19% of high proviral load (PVL, ≥4 copies of HTLV-1/100 PBMCs) carriers had an OCI-flow in the ATL range, >0.770. Carriers with an OCI-flow >0.770 (n = 14) had higher lymphocyte counts and PVLs and were more likely to have a family history of ATL than carriers with OCI-flow ≤0.770. ATL subsequently developed in two of these 14 carriers but no carriers with OCI-flow ≤0.770 (p = 0.03, cumulative follow-up 129 person-years). This method can be used to identify a subset of high-PVL HTLV-1-carriers at increased risk of developing ATL who may benefit from intervention therapy, prior to the detection of disease.

T-cell receptor antibodies expression in benign and malignant cutaneous lymphoid infiltrates in comparison with T-cell receptor gene rearrangement and its diagnostic utility in borderline cases.

INTRODUCTION: Cutaneous T-cell lymphoid infiltrate can represent reactive lesion or a malignant T-cell lymphoma. However, clinical and histopathological appearance can overlap in both groups with a risk of misdiagnosis. Aberrant expression of T-cell markers is not always applicable and T-cell receptor (TCR) gene rearrangement is not always accessible and diagnosis in borderline cases can be challenging. AIMS: Several types of TCR antibodies are currently available with limited knowledge of their expression in different cutaneous lymphoid infiltrates. Aim of the study is a comparison of expression of TCR antibodies in benign and malignant lymphoid infiltrates and their utility in borderline cases. METHODS: Representative cases of reactive and malignant lymphoproliferations were collected. Separate group of lesions with borderline morphology was selected for comparison. Immunohistochemical expression of TCR-V-betaF1 (TCRBF1), TCR-C-beta1 (TCRJOVI.1), TCR gamma/delta (TCRGD) and TCR delta (TCRD) was performed in all cases. TCR gene rearrangement evaluation was performed in all cases using PCR BIOMED-2 assay. RESULTS: Benign lymphoid infiltrates were all negative in TCRD and TCRGD. Expression of TCRJOVI.1 was seen in 3/10 cases and TCRBF1 in one. T-cell lymphomas were positive for TCRBF1 and TCRGD in 60% and 30% of cases respectively. TCR gene rearrangement was confirmed in 90% of lymphoma cases. All benign lesions were polyclonal. Morphologically borderline lesions showed expression of TCRBF1 in 6/10 cases and TCR gene rearrangement in 4/10 cases. Re-evaluation of the cases and clinical correlation led to the change of the diagnosis and confirmation of T-cell lymphoma in 4/10 cases. CONCLUSIONS: Expression of TCRBF1 and TCR-gene rearrangement was significantly associated with malignant infiltrates. TCRBF1 positivity in borderline cutaneous lymphoproliferations can raise the suspicion of malignancy but confirmation by TCR gene rearrangement and careful clinical correlation is still advisable.

CD8 expression in anaplastic large cell lymphoma correlates with noncommon morphologic variants and T-cell antigen expression suggesting biological differences with CD8-negative anaplastic large cell lymphoma.

Anaplastic large cell lymphoma (ALCL) is a T-cell neoplasm characterized by uniformly strong CD30 expression and common absence of T-cell markers. Most ALCL cases express CD4, but a small subset of ALCL cases has been reported to express CD8. Little is known about the clinicopathologic and prognostic features of CD8+ ALCL. In this study, CD8 was assessed in 158 patients with systemic ALCL: CD8 was positive in 13 of 67 (19%) ALK+ and 13 of 91 (14%) ALK-negative neoplasms. In ALK+ ALCL, the CD8+ subgroup more often showed a noncommon morphologic pattern (69% vs 13%, P = .0001) and was more often positive for CD2 (100% vs 45%, P = .001), CD3 (92% vs 24%, P = .0001), and CD7 (100% vs. 39%, P = .002), but less frequently positive for CD25 (50% vs. 100%, P = .02). Patients with ALK+ ALCL and CD8+ neoplasms also had a higher relapse rate (82% vs 48%, P = .05) and more often underwent stem cell transplant (73% vs 36%, P = .04). CD8 expression did not correlate with patient overall survival or progression-free survival regardless of ALK status (all P > 0.05). We conclude that CD8+ ALCL cases appear to be biologically different from the more common CD8-negative ALCL cases. Our data suggest that CD8 positivity in ALK+ ALCL helps to identify a subset of patients more prone to relapse or more in need of stem cell transplant during their clinical course, although there was no impact on survival in this cohort.

T-Lymphoblastic Leukemia/Lymphoma With Annular Skin Rash and Epidermotropism.

Leukemia cutis is uncommon in patients with acute lymphoblastic leukemia. It typically presents with dermal papules or subcutaneous nodules, with no epidermal or upper papillary dermal involvement on histopathology. We present an unusual clinical presentation of leukemia cutis, with annular plaques and epidermotropism.

T-cell functionality testing is highly relevant to developing novel immuno-tracers monitoring T cells in the context of immunotherapies and revealed CD7 as an attractive target.

Cancer immunotherapy has proven high efficacy in treating diverse cancer entities by immune checkpoint modulation and adoptive T-cell transfer. However, patterns of treatment response differ substantially from conventional therapies, and reliable surrogate markers are missing for early detection of responders versus non-responders. Current imaging techniques using 18F-fluorodeoxyglucose-positron-emmission-tomograpy (18F-FDG-PET) cannot discriminate, at early treatment times, between tumor progression and inflammation. Therefore, direct imaging of T cells at the tumor site represents a highly attractive tool to evaluate effective tumor rejection or evasion. Moreover, such markers may be suitable for theranostic imaging. Methods: We mainly investigated the potential of two novel pan T-cell markers, CD2 and CD7, for T-cell tracking by immuno-PET imaging. Respective antibody- and F(ab´)2 fragment-based tracers were produced and characterized, focusing on functional in vitro and in vivo T-cell analyses to exclude any impact of T-cell targeting on cell survival and antitumor efficacy. Results: T cells incubated with anti-CD2 and anti-CD7 F(ab´)2 showed no major modulation of functionality in vitro, and PET imaging provided a distinct and strong signal at the tumor site using the respective zirconium-89-labeled radiotracers. However, while T-cell tracking by anti-CD7 F(ab´)2 had no long-term impact on T-cell functionality in vivo, anti-CD2 F(ab´)2 caused severe T-cell depletion and failure of tumor rejection. Conclusion: This study stresses the importance of extended functional T-cell assays for T-cell tracer development in cancer immunotherapy imaging and proposes CD7 as a highly suitable target for T-cell immuno-PET imaging.

Automated analysis of acute myeloid leukemia minimal residual disease using a support vector machine.

We investigated the ability of support vector machines (SVM) to analyze minimal residual disease (MRD) in flow cytometry data from patients with acute myeloid leukemia (AML) automatically, objectively and standardly. The initial disease data and MRD review data in the form of 159 flow cytometry standard 3.0 files from 36 CD7-positive AML patients in whom MRD was detected more than once were exported. SVM was used for training with setting the initial disease data to 1 as the flag and setting 15 healthy persons to set 0 as the flag. Based on the two training groups, parameters were optimized, and a predictive model was built to analyze MRD data from each patient. The automated analysis results from the SVM model were compared to those obtained through conventional analysis to determine reliability. Automated analysis results based on the model did not differ from and were correlated with results obtained through conventional analysis (correlation coefficient c = 0.986, P > 0.05). Thus the SVM model could potentially be used to analyze flow cytometry-based AML MRD data automatically, objectively, and in a standardized manner.

Non-tumour bone marrow lymphocytes correlate with improved overall survival in childhood acute lymphoblastic leukaemia.

Composition of tumour immune cell infiltrates correlates with response to treatment and overall survival (OS) in several cancer settings. We retrospectively examined immune cells present in diagnostic bone marrow aspirates from paediatric patients with B-cell acute lymphoblastic leukaemia. Our analysis identified a sub-group (∼30% of patients) with >2.37% CD20 and >6.05% CD7 expression, which had 100% OS, and a sub-group (∼30% of patients) with ≤2.37% CD20 and ≤6.05% CD7 expression at increased risk of treatment failure (66.7% OS, P < 0.05). Immune cell infiltrate at diagnosis may predict treatment response and could provide a means to enhance immediate treatment risk stratification.

Homoharringtonine combined with cytarabine to treat chronic myelogenous leukemia in myeloid blast crisis and its impact on bone marrow CD34+CD7+ cells.

BACKGROUND: The therapeutic response of chronic myelogenous leukemia in myeloid blast crisis (CML-MBC) is very poor. AIM: To explore the therapeutic effect of homoharringtonine (HHT) combined with cytarabine (HA regimen) on CML-MBC and its influence on bone marrow CD34+CD7+ cells. RESULTS: Thirty-four patients with CML-MBC were treated with the HA regimen and bone marrow CD34+CD7+ cells were assayed prior to and after treatment. Among 33 evaluable patients, the overall hematological response (complete/ partial hematological response and hematological improvement) was 60.1%. Seven patients (21.2%) had a cytogenetic response 12 months after treatment. In the untreated CMLMBC patients, the proportion of bone marrow CD34+CD7+ cells was much higher than in the control group (19.4 ± 7.9 vs. 4.4 ± 1.5%, p < 0.05) and decreased to 14.1 ± 7.1% (p < 0.05) after treatment. Before treatment, the proportion of CD34+CD7+ cells was lower in the patients who had a hematological response to the HA regimen than in the patients who did not respond. CONCLUSION: The HA regimen is an effective treatment for CML-MBC and CD34+CD7+ cells may be one of the valuable clinical parameters to assess treatment effectiveness.

Normal karyotype acute myeloid leukemia with the CD7+ CD15+ CD34+ HLA-DR + immunophenotype is a clinically distinct entity with a favorable outcome.

Recently, the presence of CEBPA mutation was identified as an important prognostic factor for normal karyotype (NK) acute myeloid leukemia (AML). Because AML with CEBPA mutation is closely associated with CD7, CD15, CD34, and HLA-DR expression, we investigated the prognostic implications of CD7+ CD15+ CD34+ HLA-DR + immunophenotype in NK-AML. We analyzed the immunophenotype of 329 patients with NK-AML from the Japan Adult Leukemia Study Group (JALSG) AML97 population. NK-AML with the CD7+ CD15+ CD34+ HLA-DR + immunophenotype was classified as the CEBPA type, and NK-AML that did not meet this criterion was considered as the non-CEBPA type. The influence of the CEBPA status on event-free survival (EFS) and overall survival (OS) was assessed using log-rank test and a multivariate Cox proportional hazard regression model. Furthermore, the surface antigen expression profile in AML according to the CEBPA mutation status (monoallelic or biallelic) was also investigated. Of the 329 NK-AML patients that were studied, 39 and 243 were classified as having CEBPA and non-CEBPA type NK-AML, respectively. Patients with CEBPA type NK-AML had significantly better EFS and OS than those with non-CEBPA type NK-AML. Multivariate analysis showed that the CEBPA type and white blood cell (WBC) counts of >20 × 10(9)/L were independent prognostic factors for EFS and OS. Moreover, NK-AML with the biallelic CEBPA mutation was more closely associated with CD34 positivity than that with the monoallelic CEBPA mutation. NK-AML with the CD7+ CD15+ CD34+ HLA-DR + immunophenotype is a clinically discrete entity, and this may have a possible role in risk stratification.

Hierarchical cluster analysis of immunophenotype classify AML patients with NPM1 gene mutation into two groups with distinct prognosis.

BACKGROUND: The prognostic implication of immunophenotyping in acute myeloid leukemia (AML) patients with NPM1 mutation remains unclear. METHODS: Ninety-four of 543 AML patients diagnosed with NPM1 mutation between 1987 and 2007 were studied. The expression of surface antigens on leukemic cells was evaluated with respect to clinical manifestations and outcomes. In order to validate the prognostic effect of the immunophenotypic cluster, another 36 patients with NPM1 mutation diagnosed between 2008 and 2010 were analyzed. RESULTS: Ninety-four patients with NPM1 mutations and complete immunophenotyping data were enrolled for a hierarchical cluster analysis and the result was correlated with clinico-laboratory characteristics. Clustering analysis divided the patients with NPM1 mutations into the following two groups: group I, CD34(-)/CD7(-), but with variable expression of HLA-DR; and group II, HLA DR(+)/CD34(+)/CD7(+). With a median follow-up of 53 months, the group II patients had a significantly shorter relapse-free survival (RFS, median: 3 vs. 23 months, p = 0.006) and overall survival (OS, median: 11 vs. 40 months, p = 0.02) than group I patients. Multivariate analysis of variables, including clinico-laboratory data and other gene mutations revealed that the immunophenotypic cluster is an independent prognostic factor (RFS, p = 0.002; OS, p = 0.024). In order to confirm the prognostic effect of the immunophenotypic cluster, another 36 patients with NPM1 mutation diagnosed between 2008 and 2010 were validated. Hierarchical cluster analysis also showed two distinct clusters, group I patient showed significant better RFS (p = 0.021), and OS (p = 0.055). In total, we stratified 130 NPM1-mutant patients, by FLT3-ITD mutation and immunophenotypic cluster into distinct prognostic groups (RFS, p < 0.001 and OS, p = 0.017). CONCLUSIONS: Among NPM1-mutated AML, the antigen expression pattern of HLADR(+) CD34(+) CD7(+) is associated with a poor prognosis, independent to the FLT3-ITD mutation.

Simplified flow cytometric assessment in mycosis fungoides and Sézary syndrome.

By using flow cytometry with markers for CD3, CD4, CD26, and CD7, we examined the blood samples of 109 patients for abnormal T cells: 69 patients with mycosis fungoides (MF)/Sézary syndrome (SS), 31 hospitalized control subjects, and 9 patients with inflammatory skin disease. T cells were identified as quantitatively abnormal (>15% CD26- or CD7- T cells) or phenotypically abnormal (CD26- or CD7- T cells with bright or dim CD3 or CD4 or bright CD7). Patients were followed for a median of 82 months, and abnormal T cells were correlated with diagnosis, clinical outcome, and other laboratory parameters. Abnormal T-cell populations were identified in 46% of patients with MF/SS (32/69) and correlated with disease extent. Quantitative abnormalities were more frequent than phenotypic abnormalities, and CD4+/CD26- T cells were more frequent than CD4+/CD7- T cells. CD26- T cells correlated better with disease extent than did CD7 -. Increasing numbers of abnormal T cells were associated with worsening disease. Flow cytometry provides valuable information for diagnosis, prognosis, and therapeutic efficacy in MF/SS.

Expression of CD34 and CD7 on human T-cell acute lymphoblastic leukemia discriminates functionally heterogeneous cell populations.

Leukemia-initiating/repopulating cells (LICs), also named leukemic stem cells, are responsible for propagating human acute leukemia. Although they have been characterized in various leukemias, their role in T-cell acute lymphoblastic leukemia (T-ALL) is unclear. To identify and characterize LICs in T-ALL (T-LIC), we fractionated peripheral blood cell populations from patient samples by flow cytometry into three cell fractions by using two markers: CD34 (a marker of immature cells and LICs) and CD7 (a marker of early T-cell differentiation). We tested these populations in both in vitro culture assays and in vivo for growth and leukemia development in immune-deficient mice. We found LIC activity in CD7(+) cells only as CD34(+)CD7(-) cells contained normal human progenitors and hematopoietic stem cells that differentiated into T, B lymphoid and myeloid cells. In contrast, CD34(+)CD7(+) cells were enriched in LICs, when compared with CD34(-)CD7(+) cells. These CD34(+)CD7(+) cells also proliferated more upon NOTCH activation than CD34(-)CD7(+) cells and were sensitive to dexamethasone and NOTCH inhibitors. These data show that CD34 and CD7 expression in human T-ALL samples help in discriminating heterogeneous cell populations endowed with different LIC activity, proliferation capacity and responses to drugs.

Leukemic T cells are specifically enriched in a unique CD3(dim) CD7(low) subpopulation of CD4(+) T cells in acute-type adult T-cell leukemia.

The morphological discrimination of leukemic from non-leukemic T cells is often difficult in adult T-cell leukemia (ATL) as ATL cells show morphological diversity, with the exception of typical "flower cells." Because defects in the expression of CD3 as well as CD7 are common in ATL cells, we applied multi-color flow cytometry to detect a putative leukemia-specific cell population in the peripheral blood from ATL patients. CD4(+) CD14(-) cells subjected to two-color analysis based on a CD3 vs CD7 plot clearly demonstrated the presence of a CD3(dim) CD7(low) subpopulation in each of nine patients with acute-type ATL. The majority of sorted cells from this fraction showed a flower cell-like morphology and carried a high proviral load for the human T-cell leukemia virus type 1 (HTLV-I). Genomic integration site analysis (inverse long-range PCR) and analysis of the T cell receptor Vß repertoire by flow cytometry indicated that the majority of leukemia cells were included in the CD3(dim) CD7(low) subpopulation. These results suggest that leukemic T cells are specifically enriched in a unique CD3(dim) CD7(low) subpopulation of CD4(+) T cells in acute-type ATL.

FLT3 and NPM1 mutations in Chinese patients with acute myeloid leukemia and normal cytogenetics.

Mutations of fms-like tyrosine kinase 3 (FLT3) and nucleophosmin (NPM1) exon 12 genes are the most common abnormalities in adult acute myeloid leukemia (AML) with normal cytogenetics. To assess the prognostic impact of the two gene mutations in Chinese AML patients, we used multiplex polymerase chain reaction (PCR) and capillary electrophoresis to screen 76 AML patients with normal cytogenetics for mutations in FLT3 internal tandem duplication (FLT3/ITD) and exon 12 of the NPM1 gene. FLT3/ITD mutation was detected in 15 (19.7%) of 76 subjects, and NPM1 mutation in 20 (26.3%) subjects. Seven (9.2%) cases were positive for both FLT3/ITD and NPM1 mutations. Significantly more FLT3/ITD aberration was detected in subjects with French-American-British (FAB) M1 (42.8%). NPM1 mutation was frequently detected in subjects with M5 (47.1%) and infrequently in subjects with M2 (11.1%). FLT3 and NPM1 mutations were significantly associated with a higher white blood cell count in peripheral blood and a lower CD34 antigen expression, but not age, sex, or platelet count. Statistical analysis revealed that the FLT3/ITD-positive group had a lower complete remission (CR) rate (53.3% vs. 83.6%). Survival analysis showed that the FLT3/ITD-positive/NPM1 mutation-negative group had worse overall survival (OS) and relapse-free survival (RFS). The FLT3/ITD-positive/NPM1 mutation-positive group showed a trend towards favorable survival compared with the FLT3/ITD-positive/NPM1 mutation-negative group (P=0.069). Our results indicate that the FLT3/ITD mutation might be a prognostic factor for an unfavorable outcome in Chinese AML subjects with normal cytogenetics, while NPM1 mutation may be a favorable prognostic factor for OS and RFS in the presence of FLT3/ITD.