An effective and chemotherapy-free strategy of all-trans retinoic acid and arsenic trioxide for acute promyelocytic leukemia in all risk groups (APL15 trial).

The combination of all-trans retinoic acid (ATRA) and arsenic trioxide (ATO) has been demonstrated to have comparable effectiveness or better to ATRA and chemotherapy (CHT) in non-high-risk acute promyelocytic leukemia (APL). However, the efficacy of ATRA-ATO compared to ATRA-ATO plus CHT in high-risk APL remains unknown. Here we performed a randomized multi-center non-inferiority phase III study to compare the efficacy of ATRA-ATO and ATRA-ATO plus CHT in newly diagnosed all-risk APL to address this question. Patients were assigned to receive ATRA-ATO for induction, consolidation, and maintenance or ATRA-ATO plus CHT for induction followed by three cycles of consolidation therapy, and maintenance therapy with ATRA-ATO. In the non-CHT group, hydroxyurea was used to control leukocytosis. A total of 128 patients were treated. The complete remission rate was 97% in both groups. The 2-year disease-free, event-free survival rates in the non-CHT group and CHT group in all-risk patients were 98% vs 97%, and 95% vs 92%, respectively (P = 0.62 and P = 0.39, respectively). And they were 94% vs 87%, and 85% vs 78% in the high-risk patients (P = 0.52 and P = 0.44, respectively). This study demonstrated that ATRA-ATO had the same efficacy as the ATRA-ATO plus CHT in the treatment of patients with all-risk APL.

Toxic epidermal necrolysis syndrome induced by tigecycline: a case report.

A 56-year-old man diagnosed with non-Hodgkin's lymphoma underwent autologous bone marrow transplantation. He was subsequently admitted to the hospital with fever, and his symptoms were initially controlled by multiple antibiotics, including tigecycline. He then developed a generalized body rash that improved after treatment with anti-allergy drugs and steroids. Furthermore, tigecycline treatment for a second time resulted in a severe skin reaction with systemic symptoms, suggesting toxic epidermal necrolysis syndrome (TEN). The patient was shown to have the slow-metabolizing cytochrome P450 2C19 allele, denoted CYP2C19*2. He was transferred to a laminar flow ward and given strict mucosal care, together with corticosteroids and intravenous immunoglobulin. He recovered after 3 weeks of treatment. Tigecycline-induced Stevens-Johnson syndrome (SJS)/TEN has rarely been reported in the Chinese population. However, our experience suggests that Asians are more likely to have adverse reactions to drugs metabolized by the cytochrome P450 enzyme. Early identification of drug reactions and immediate cessation of the suspected drug is essential. Additionally, a combined therapy scheme and a clean laminar flow environment may improve the cure rate of SJS/TEN.

High proportions of CD3+ T cells in grafts delayed lymphocyte recovery and reduced overall survival in haploidentical peripheral blood stem cell transplantation.

T cells in grafts serve an important role in the pathogenesis of graft versus host disease (GVHD) and immune recovery during HLA matched allogeneic stem cell transplantation. However, the role of T cells in the haploidentical peripheral blood stem cell transplantation (Haplo-PBSCT) is yet to be determined. In the present study, the role of CD3+ T cells in grafts and impact on hematopoietic and immune recovery, cytomegalovirus (CMV) reactivation, GVHD, relapse, progress free survival and overall survival (OS) were evaluated and analyzed. A total of 30 patients who underwent haplo-PBSCT were included in the present study. CD3+ T cells accounted for a median of 23.1% (range 8-47.4%) with a median dose of 299.7x106/kg (range 104-623.4). Patients were divided into two groups according to the CD3+ T cell count: Above the median (high T cell group) and below the median CD3+ T cell (low T cell group). No significant difference was identified between neutrophil and platelet recovery time between two groups (P>0.05). The mean lymphocyte recovery time of high T cell group and low T cell group were 107.07 days (95% CI 79.88-134.25), and 50.4 days (95% CI 41.42-59.38), respectively. The lymphocyte recovery time of high T cell group was higher that of low T cell group (P<0.05). No significant difference between CMV reactivation, chronic GVHD and primary disease relapse rates was observed between two groups (P>0.05). The cumulative incidence of grade II or above acute GVHD was higher in the high T groups compared with low T groups (P<0.05). The overall survival and progress free survival rates were higher in the low T cell group compared with the high T cell group (P<0.05). In conclusion, high levels of CD3+ T cells in the grafts were associated with delayed lymphocyte recovery and an increased risk of acute GVHD and decreased overall survival.

Treatment of non-high-risk acute promyelocytic leukemia with realgar-indigo naturalis formula (RIF) and all-trans retinoid acid (ATRA): study protocol for a randomized controlled trial.

BACKGROUND: Acute promyelocytic leukemia (APL) is a highly curable disease when treated with all-trans retinoid acid (ATRA) and arsenic trioxide (ATO). The combination of ATO and ATRA has become the standard therapeutic protocol for induction therapy in non-high-risk APL. An oral arsenic realgar-indigo naturalis formula (RIF) has also showed high efficacy and it has a more convenient route of administration than the standard intravenous regimen. Unlike in previous trials, the arsenical agent was used simultaneously with ATRA during post-remission therapy in this trial. METHODS: This study was designed as a multicenter, randomized controlled trial. The trial has a non-inferiority design with superiority being explored if non-inferiority is identified. All patients receive ATRA-ATO during the induction therapy. After achieving hematologic complete remission (HCR), patients were randomly assigned (1:1) to receive treatment with ATRA-RIF (experimental group) or ATRA-ATO (control group) as the consolidation therapy. During the consolidation therapy, the two groups receive ATRA plus RIF or intravenous ATO 2 weeks on and 2 to ~ 4 weeks off until molecular complete remission (MCR), then ATRA and oral RIF 2 weeks on and 2 to ~ 4 weeks off giving a total of six courses. DISCUSSION: This trial aims to compare the efficacy of ATRA-ATO versus ATRA-RIF in non-high-risk patients with APL, to demonstrate that oral RIF application reduces the total hospitalization days and medical costs. The simple schedule was studied in this trial. TRIAL REGISTRATION: ClinicalTrials.gov, NCT02899169. Registered on 14 September 2016.

Dynamic changes in the level of WT1 as an MRD marker to predict the therapeutic outcome of patients with AML with and without allogeneic stem cell transplantation.

Monitoring minimal residue disease (MRD) is an effective approach to evaluate the response to chemotherapy, and it is used to select the ideal therapeutic strategy and to predict the recurrence during therapy for hematological disorders. The Wilm's tumor 1 (WT1) gene, which is highly expressed in >80% of patients with acute myeloid leukemia (AML) and its increased expression level may cause poor clinical outcomes, is a potential MRD marker of hematological neoplasms. In the present study, the expression levels of WT1 and other molecular markers were retrospectively analyzed by reverse transcription­quantitative PCR in 195 patients with AML. The expression level of WT1 was significantly lower in patients with remission compared with patients with early­stage and recurrent AML. Moreover, WT1 expression was significantly decreased in patients with RUNX family transcription factor 1­RUNX1 translocation partner 1 fusion, but higher in patients with promyelocytic leukemia­retinoic acid receptor α fusion. WT1 expression was significantly reduced during remission. In patients with AML who underwent allogeneic hematopoietic stem cell transplantation (allo­HSCT), the mortality rate 2 years after allo­HSCT was significantly lower in patients with low expression level of WT1 compared with subjects presenting high expression level of WT1. Collectively, the upregulation of the expression level of WT1 in combination with the identification of other genetic abnormalities may be used as MRD markers of hematological neoplasms.

Simultaneous Hodgkin lymphoma and BRAFV600E-positive papillary thyroid carcinoma: A case report.

RATIONALE: Papillary thyroid carcinoma (PTC) is the most common endocrine malignancy. However, the simultaneous occurrence of PTC and Hodgkin Lymphoma (HL) was rarely reported. PATIENT CONCERNS: We present a case of simultaneous BRAF-positive PTC and HL in a 17-year-old female. DIAGNOSIS: She was referred to our clinic with a painless lump in her left neck. A highly suspicious thyroid nodule and multiple enlarged lymph nodes in the neck were found by ultrasonography examination. The suspicious nodule was diagnosed as PTC by fine needle aspiration cytology. INTERVENTIONS: A total thyroidectomy with bilateral lymph node dissection was performed and the microscopic examination revealed a 2-cm PTC with BRAF mutation and HL (mixed cellularity) in the bilateral lymph nodes. PTC was postoperatively considered as T1bN0M0. Levothyroxine (125 µg/d) was administered to the patient for thyrotropin suppression therapy. Then the patient was referred to the Department of Hematology to receive 4 cycles of ABVD followed by 30 Gy involved-site radiotherapy and radioactive iodine (RAI) therapy for thyroid cancer. OUTCOMES: After two cycles of ABVD, multiple enlarged lymph nodes showed a significant response to the chemotherapy in the patient. LESSONS: Simultaneous HL and BRAF-positive PTC is extremely rare. Biopsy of the suspicious lymph nodes should be performed to confirm malignancy metastasizing from PTC or other lesions. Similarly, in HL patients with suspicious thyroid nodule, ultrasound-guided fine needle aspiration of thyroid nodule should be performed to exclude thyroid malignancy.

Arsenic trioxide and all-trans retinoic acid (ATRA) treatment for acute promyelocytic leukemia in all risk groups: study protocol for a randomized controlled trial.

BACKGROUND: The treatment of acute promyelocytic leukemia (APL) has been revolutionized in the past two decades by the advent of all-trans retinoic acid (ATRA) and arsenic trioxide (ATO). It suggests that non-high-risk APL patients can be cured without chemotherapy. However, ATRA plus chemotherapy is still the standard therapy for the high-risk patients. Central nervous system (CNS) relapse remains a significant cause of treatment failure in high-risk patients. However, increasing the ATO concentration in cerebrospinal fluid (CSF) may reduce CNS relapse in high-risk patients. Mannitol can allow ATO to penetrate the blood-brain barrier (BBB) and reach therapeutically effective levels in the CSF. It is used for the treatment of CNS relapse in patients APL. We compare ATRA-ATO with ATRA-ATO plus chemotherapy in both high-risk and non-high-risk patients with APL. METHODS: This study was designed as a multicenter randomized controlled trial. Patients with APL were randomly assigned into two groups: the ATRA-ATO group (experimental group) and the ATRA-ATO plus chemotherapy group (control group). The experimental group receives therapy with ATRA-ATO for induction, consolidation and maintenance therapy. In the high-risk patients, mannitol will be used with ATO in the consolidation and maintenance therapy. Hydroxyurea will be used in patients who developed leukocytosis in the induction therapy. The control group receives therapy with ATRA-ATO plus chemotherapy for induction and consolidation therapy. DISCUSSION: In this study, a randomized clinical trial design is described. It aims to compare the efficacy of ATRA-ATO versus ATRA-ATO plus chemotherapy in all-risk patients with APL. TRIAL REGISTRATION: Chinese Clinical Trials Registry, ID: ChiCTR-IPR- 15006821 . Registered on 27 July 2015.

[Relationship between the Therapeutic Dose of Arsenic Trioxide and Relapse in Acute Promyelocytic Leukemia].

OBJECTIVE: To analyze the correlation of ATO therapeutic dose with the relapse of patients with acute promyelocytic leukemia (APL) and to investigate the optimal dose and courses of ATO. METHODS: The clinical data of 102 patients with APL from January 2008 to June 2015 were analyzed retrospectively. The clinical characteristics of APL patients in relapsed group and maintained remission group were compared. According to ATO dose in 2 years recommended in chinese guideline as criteria of grouping, the patients were divided into ATO high and low dose groups, then the relapse rate in groups was compared. The cut-off value of ATO dose was analyzed by ROC curve. RESULTS: Univariate analysis showed that the relapse rate in high ATO and low ATO groups on 2 year treatment was 2.5% and 17.7% respectively (P<0.05); multiple variate analysis demonstrated that the ATO dose>22.4 mg/kg on 2 year treatment was independent preventive factor for the relapse of APL (OR=0.119, P<0.05). The ROC curve showed that the cut-off value of ATO dose on 2 year treatment was 8.765 mg/kg. The relapse rate of APL in group of ATO dose >8.765 mg/kg group was significantly lower than that in group of ATO dose <8.765 mg/kg. CONCLUSION: The relapse of APL relates with used ATO dose, sufficient use of ATO dose can decrease the relapse rate of APL.

[Relationship between Peripheral Blood White Blood Cell Count and Early Death Rate in Patients with Acute Promyelocytic Leukemia].

OBJECTIVE: To investigate the relationship between peripheral white blood cell count and early death rate of the patients with acute promyelocytic leukemia (APL). METHODS: Through retrospective study, the relationship of early death rate in 116 cases newly diagnosed APL patients with maximum of peripheral blood white blood cell count should be analyzed before and after induction therapy as well as in the whole course of disease during the past 8 years. RESULTS: There was a close relationship between the peripheral white blood cell count and the early death rate in APL patients. Peripheral blood white blood cell count in the early died patients was significantly higher than that of the survival patients (P<0.05). ROC analysis showed that the highest risk threshold of peripheral white cell count was 70×109/L (P<0.05) before treatment, while the highest risk threshold after treatment and in the whole course of disease were 96.4×109/L(P<0.05) and 91.5×109/L(P<0.01) respectively. The dealth rate of patients with highest risk threshold was significantly increased (P<0.05). CONCLUSION: The highest peripheral blood white blood cell count closely relates with the early death rate of patients at different time points in the whole course of disease. Control of peripheral white blood cell count may effectively reduce the early death rate of APL patients.

[Risk Factors and Therapeutic Outcome of Intestinal Acute Graft Versus Host Disease in Acute Leukemia Patients after Haploidentical Peripheral Hematopoietic Stem Cell Transplantation].

OBJECTIVE: To investigate the risk factors and therapeutic outcome of acute graft versus host disease (aGVHD) in patients with acute leukemia after haploidentical peripheral hematopoietic stem cell transplantation. METHODS: The clinical data of 19 cases of acute leukemia underwent haploidentical hematopoietic stem cell transplanttion during January 2010 and December 2010 were retrospectively analyzed. The effects of patients sex, donor-recipient sex difference, donor age, conditioning regimen, dosage of anti-thymocyte globulin(ATG), mononuclear cell and CD34+ cell counts on the intestinal aGVHD were analyzed by Logistic regression. RESULTS: Intestinal aGVHD occurred in 5 cases with 1 case at stage II 3 cases at stage III and 1 case at stage IV on the 7th, 22th, 27th, 70th and 154th day after transplantation, respectively. Single factor analysis showed that the patient's sex, donor-recipient sex difference, donor age, dosage of ATG, mononuclear cell and CD34+ cell counts were not related with the occurrence of the intestinal aGVHD, and the conditoning regimen was the risk factor for the intestinal aGVHD. 2 cases among 5 cases with intestinal aGVHD were treated with methylprednisolone at dosage of 1 mg/kg per day, 1 case was treated with methylprednisolone therapy combined with tacrolimus. 2 cases of methylprednisolone-resistance were treated with CD25 monoclonal antibody. Intestinal aGVHD of all patients was improved after the above-mentioned treatment. CONCLUSION: Conditioning regimen of haploidentical peipheral hematopoieitc stem cell transplantaion has effects on the intestinal aGVHD, which needs to be confirmed by further research.

Arsenic Trioxide Combined with VCMP or VAD Chemotherapy in Patients with Refractory or Relapsed Multiple Myeloma in a Single Institution of China.

Arsenic trioxide (ATO) combined with dexamethasone, melphalan or other cytostatic agents had been used to treat refractory or relapsed multiple myeloma (MM) patients. We assessed the safety and efficacy of ATO combined with vindesine/cyclophosphamide/melphalan/prednisone (VCMP) or vindesine/doxorubicin/dexamethsone (VAD) chemotherapy for MM patients who failed more than two different prior regimens. All patients received ATO (0.25 mg/kg day) for 10 days/cycle combined with VCMP or VAD in 30-day cycles. Vindesine (1.4 mg/m(2)) was given intravenously on day 1, cyclophosphamide (400 mg/m(2) day) was given intravenously on days 2, 4, 6, 8, 10, melphalan (6 mg/day) and prednisone (1 mg/kg day) were given orally day 1 to day 10 for VCMP regimen. VAD regimen consisted of vindesine 1 mg/day and doxorubicin 10 mg/day intravenously drip for 4 days with oral dexamethasone 40 mg/day for days 1-4, 9-12, 17-20. Patients who completed at least one cycle were evaluated for response to treatment. Objective responses occurred in 35 of 63 (56 %) patients, including seven complete, 14 partial and 14 minor responses. Median progression-free survival and overall survival were 6 and 23 months respectively. 12 patients had elevated serum creatinine levels (SCr) at baseline, and 9 of 12 (75 %) showed decreased SCr levels during treatment. Frequent Grade 3/4 non-hematological adverse events included arrhythmia, hypertension, fatigue and neuropathy. These results indicate that ATO combined with VCMP or VAD was effective and well tolerated as a new therapeutic option for patients with relapsed or refractory MM.

[WT1 gene expression difference in leukemia and non-leukemia and its clinical significance].

This study was aimed to investigate the expression level of Wilms' tumor 1( WT1) gene in hematologic neoplasm (leukemia, multiple myeloma and lymphoma) patients and its clinical significance. Real-time quantitative polymerase chain reaction (RQ-PCR) was used to detect the copy number of WT1 gene and reference gene (ALB) in bone marrow cells of 228 patients with hematologic neoplasm in our hospital. The gene expression level was determined by using the ratio of the copy number of WT1 gene and reference gene. The results showed that the WT1 expression level between male and female patients was not statistically significantly different (P > 0.05). All the patients were divided into 3 groups: the group aged under 19, the group aged between 19-50, and the group aged over 50; the WT1 expression level among the three groups were not statistically significantly different (P > 0.05) . The above-mentioned patients were redivided into the groups aged under 45 and over 45, the difference between them was not statistically significant (P > 0.05). The difference of WT1 expression level between newly diagnosed patients and treated patients with hematologic neoplasm was statistically significant (P < 0.01), but no statistically significant difference of WT1 expression was found (P > 0.05) at each stage within 3 years after treatment, however, among them the difference between newly diagnosed leukemia patients and treated leukemia patients was very statistically significant (P < 0.01), while the difference between newly diagnosed and treated non-leukemia patients was not statistically significant (P > 0.05). The expression difference of WT1 between leukemia and non-leukemia patients was very statistically significant (P < 0.01), the difference between the newly diagnosed leukemia and non-leukemia patients also was very statistically significant (P < 0.01). The difference of WT1 expression between treated leukemia and non-leukemia patients was not statistically significant (P > 0.05). It is concluded that the WT1 expression level in leukemia patients can be a reliable marker to evaluate the prognosis of newly diagnosed leukemia and the curative effect for minimal residual disease. No WT1 expression difference has been found before and after treatment among the patients with non-leukemia, such as multiple myeloma and lymphoma, therefore, which should be furtherly explored.

[Relation of reinfused hematopoietic stem cell volume and recipient's leukocyte count at reinfusion with prognosis of disease in allo-hematopoietic stem cell transplantation].

This study was aimed to investigate the relation of reinfused hematopoietic stem cell volume and recipient's leukocyte count at reinfusion with prognosis of disease in allo-hematopoietic stem cell transplantation (allo-HSCT). The clinical data of 37 patients received allo-HSCT in our hospital were analyzed retrospectively. The 37 patients were divided into agranulocytosis and non-agranulocytosis groups according to the recipient's leukocyte count at reinfusion, and were divided into the high dose and low dose groups according to the median number of reinfused mononuclear cells (MNC) and CD34(+) cells. Then, hematopoietic reconstructions,GVHD, relapse and death rates of patients were compared. The results showed that the hematopoietic reconstruction of patients in non-agranulocytosis group and high dose MNC group were earlier than that in agranulocytosis group and low dose MNC group. There was no significant difference of hematopoietic reconstruction between the groups of high dose CD34(+) cells and low dose CD34(+) cells. The GVHD incidence was higher in high dose MNC group and non-agranulocytosis group than that in low dose MNC group and agranulocytosis group (P < 0.05). There were no statistical differences of relapsed and death rates between different reinfused number of HSC and recipient's leukocyte count at reinfusion.It is concluded that the infused MNC number and the recipient's leukocyte count at reinfusion in allo-HSCT correlated with hematopoietic reconstruction, the GVHD incidence is high in high dose MNC and non-agranulocytosis groups, the reinfused HSC volume and the recipient's leukocyte count at reinfusion not significantly relate with relapse and death rates.

[Effect of dexamethasone on G-CSF mobilization of peripheral blood stem cells in healthy donors and hematopoietic reconstruction in the recipients].

This study was aimed to investigate the effects of different mobilization methods on mobilization and collection of peripheral blood stem cells in healthy donors and the adverse effect of collection, as well as hematopoietic construction in recipients. A total of 43 donors between January 2008 and May 2013 were divided into the simple mobilization group and the combined mobilization group. The simple group was subcutaneously injected with 5.0-10.0 µg/(kg·d) recombinant human granulocyte colony-stimulating factor (rhG-CSF), and the combined mobilization group was treated with rhG-CSF and intravenously dripped with 10 mg dexamethasone for 2-4 hours before collection. The acquisition and count of MNC and CD34(+) cells in different groups, the relationship between the stem cells and MNC count in blood before collection, and the adverse reactions were analyzed; the hematopoietic reconstruction of recipients was investigated. The results showed that the hematopoietic stem cell number of the two groups meet the demands. The count of MNC and CD34(+) cells in the simple mobilization group was more than that in the combined mobilization group. The MNC count in two groups positively correlated with peripheral blood MNC count before collection. The decline of hemoglobin and platelet levels was more obvious in the simple mobilization group than that in combined mobilization group. The adverse reactions of collection in the simple mobilization group could be well tolerated and reversed. There was no adverse reaction in the combined mobilization group. The differences of conditioning regimens between two groups were not statistically significant and the hematopoietic reconstruction time of combined group was shorter than that in the simple mobilization group.It is concluded that the adverse reactions in process of collection can be reduced, and enough hematopoietic stem cells can be collected by G-CSF plus dexamethasone in mobilization of peripheral blood stem cells. The count of MNC in peripheral blood before collection can be still used as a reference index to evaluate the acquisition of MNC. Especially the combination with dexamethasone for stem cell mobilization can promote the hematopoietic reconstruction of the recipients.

Interferon-γ enhances promyelocytic leukemia protein expression in acute promyelocytic cells and cooperates with all-trans-retinoic acid to induce maturation of NB4 and NB4-R1 cells.

In order to investigate the effect and mechanisms of interferon (IFN)-γ in combination with all-trans-retinoic acid (ATRA) on NB4 cells [ATRA-sensitive acute promyelocytic leukemia (APL) cell line] and NB4-R1 cells (ATRA-resistant APL cell line) and to search for a novel approach to solve the problem of ATRA resistance in APL, we initially treated NB4 and NB4-R1 cells with IFN-γ, ATRA and IFN-γ in combination with ATRA, respectively. The cell proliferation was then tested by MTT assay, and the cell differentiation was tested through light microscopy, by NBT test and flow cytometry (FCM). The expression of promyelocytic leukemia (PML) protein was observed by indirect immune fluorescent test. Results showed that ATRA inhibited the growth of NB4 cells, however, it could not inhibit the growth of NB4-R1 cells. IFN-γ inhibited the growth of both NB4 and NB4-R1 cells. Meanwhile, the growth inhibition effect of IFN-γ in combination with ATRA on both NB4 and NB4-R1 cells was significantly stronger than that of any single drug treatment. The results of the NBT reduction test and CD11b antigen detection by FCM indicated that IFN-γ induces the differentiation of NB4 and NB4-R1 cells to some extent. Moreover, the maturation degree of both NB4 and NB4-R1 cells induced by IFN-γ in combination with ATRA was more significant than that of IFN-γ or ATRA alone. After treatment with IFN-γ, the number of fluorescent particles in NB4 and NB4-R1 cell nuclei was higher than those in the control group, which indicated that IFN-γ may induce the expression of PML protein. Together, IFN-γ augments the proliferation inhibition effect of ATRA on NB4 and NB4-R1 cells through enhancing the expression of PML protein. IFN-γ in combination with ATRA not only strengthens the induction differentiation effect of ATRA on NB4 cells, but also can partially induce the maturation of NB4-R1 cells with ATRA resistance.

Establishment of two-dimensional gel electrophoresis profiles of the human acute promyelocytic leukemia cell line NB4.

To explore optimum conditions for establishing a two­dimensional gel electrophoresis (2-DE) map of the human acute promyelocytic leukemia (APL) cell line NB4 and to analyze its protein profiles, we extracted total proteins from NB4 cells using cell disruption, liquid nitrogen freeze-thawing and fracturing by ultrasound, and quantified the extracted protein samples using Bradford's method. 2-DE was applied to separate the proteins, which were silver-stained in the gel. Well­separated protein spots were selected from the gel using the ImageMaster™ 2D Platinum analysis system. Moreover, the effects of various protein sample sizes (140, 160 and 180 µg) on the 2-DE maps of the NB4 cells were determined and compared. Matrix-assisted laser desorption/ionization time of flight-mass spectrometry (MALDI-TOF-MS), peptide mass fingerprinting (PMF) and database searching were used to identify the proteins. When the quantity of loading proteins was 160 µg, clear, well-resolved, reproducible 2-DE proteomic profiles of the NB4 cells were obtained. The average number of protein spots in 3 gels was 1160±51 with an average matching rate of 81%. A total of 10 proteins were identified by mass spectrometry and database queries, certain proteins were products of oncogenes and others were involved in cell cycle regulation and signal transduction. In summary, 2-DE profiles of the proteome of NB4 cells were established and certain proteins were identified by MALDI-TOF-MS and PMF which lay the foundation of further proteomic research of NB4 cells. These data should be useful for establishing a human APL proteome database.