CD7 expression predicts poor disease free survival and post-remission survival in patients with acute myeloid leukemia and normal karyotype

Naturally selected CD7-directed CAR-T bridging allo-HSCT in refractory acute myeloid leukemia: a case report and review

Relapsed/refractory acute myeloid leukemia (R/R-AML) has a poor prognosis. CD7 is expressed in leukemic cells in 30% of patients with AML but not in normal myeloid cells. Therefore, it can be a potential target for immunotherapy in patients with R/R-AML. Naturally selected CD7-directed chimeric antigen receptor T cells (CAR-T) have promising effects against AML based on xenotransplantation models. We report a R/R-AML case that achieved complete remission with incomplete hematologic recovery with naturally selected CD7 CAR-T therapy. Allogeneic hematopoietic stem cell transplantation (allo-HSCT) as consolidation early after CAR T therapy, the patient experienced 12 months of disease-free survival to date. Our results confirmed that allogeneic hematopoietic stem cell transplantation after naturally selected CD7 CAR-T therapy can be a potential treatment for patients with CD7-positive R/R-AML.

Sequential CD7 CAR T-Cell Therapy and Allogeneic HSCT without GVHD Prophylaxis

BACKGROUND

Patients with relapsed or refractory hematologic cancers have a poor prognosis. Chimeric antigen receptor (CAR) T-cell therapy as a bridge to allogeneic hematopoietic stem-cell transplantation (HSCT) has the potential for long-term tumor elimination. However, pre-HSCT myeloablation and graft-versus-host disease (GVHD) prophylaxis agents have toxic effects and could eradicate residual CAR T cells and compromise antitumor effects. Whether the integration of CAR T-cell therapy and allogeneic HSCT can preserve CAR T-cell function and improve tumor control is unclear.

METHODS

We tested a novel "all-in-one" strategy consisting of sequential CD7 CAR T-cell therapy and haploidentical HSCT in 10 patients with relapsed or refractory CD7-positive leukemia or lymphoma. After CAR T-cell therapy led to complete remission with incomplete hematologic recovery, patients received haploidentical HSCT without pharmacologic myeloablation or GVHD prophylaxis drugs. Toxic effects and efficacy were closely monitored.

RESULTS

After CAR T-cell therapy, all 10 patients had complete remission with incomplete hematologic recovery and grade 4 pancytopenia. After haploidentical HSCT, 1 patient died on day 13 of septic shock and encephalitis, 8 patients had full donor chimerism, and 1 patient had autologous hematopoiesis. Three patients had grade 2 HSCT-associated acute GVHD. The median follow-up was 15.1 months (range, 3.1 to 24.0) after CAR T-cell therapy. Six patients remained in minimal residual disease-negative complete remission, 2 had a relapse of CD7-negative leukemia, and 1 died of septic shock at 3.7 months. The estimated 1-year overall survival was 68% (95% confidence interval [CI], 43 to 100), and the estimated 1-year disease-free survival was 54% (95% CI, 29 to 100).

CONCLUSIONS

Our findings suggest that sequential CD7 CAR T-cell therapy and haploidentical HSCT is safe and effective, with remission and serious but reversible adverse events. This strategy offers a feasible approach for patients with CD7-positive tumors who are ineligible for conventional allogeneic HSCT. (Funded by the National Natural Science Foundation of China and the Key Project of Science and Technology Department of Zhejiang Province; ClinicalTrials.gov numbers, NCT04599556 and NCT04538599.).

CD7-positive leukemic blasts with DNMT3A mutations predict poor prognosis in patients with acute myeloid leukemia

Background

DNMT3A mutations can be detected in premalignant hematopoietic stem cells and are primarily associated with clonal hematopoiesis of indeterminate potential; however, current evidence does not support assigning them to a distinct European Leukemia Net (ELN) prognostic risk stratification. CD7 is a lymphoid antigen expressed on blasts in approximately 30% of acute myeloid leukemia (AML), and its role in AML remains unclear and depends on subgroup evaluation. This study investigated the prognostic value of DNMT3A mutation combined with CD7 expression in AML.

Methods

We retrospectively analyzed the clinical data of 297 newly diagnosed non-M3 AML patients. According to the DNMT3A mutation and CD7 expression in AML cells, patients were divided into the DNMT3A-mutated/CD7-positive (CD7+), DNMT3A-mutated/CD7-negative (CD7-), DNMT3A-wild-type/CD7+, and DNMT3A-wild-type/CD7- groups.

Results

The DNMT3A-mutated/CD7+ group had lower complete remission rates and higher relapse rates. Importantly, these patients had significantly shorter overall survival (OS) and relapse-free survival (RFS). Furthermore, multivariate analysis showed that CD7+ with DNMT3A mutation was an independent risk factor for OS and RFS.

Conclusion

CD7+ with DNMT3A mutation predicts a poor prognosis in AML patients, and the immunophenotype combined with molecular genetic markers can help to further refine the current risk stratification of AML.

Prevalence and clinical impact of CD56 and T-cell marker expression in acute myeloid leukaemia: A single-centre retrospective analysis

Flow cytometry-based immunophenotyping is a mainstay of diagnostics in acute myeloid leukaemia (AML). Aberrant CD56 and T-cell antigen expression is observed in a fraction subset of AML cases, but the clinical relevance remains incompletely understood. Here, we retrospectively investigated the association of CD56 and T-cell marker expression with disease-specific characteristics and outcome of 324 AML patients who received intensive induction therapy at our centre between 2011 and 2019. We found that CD2 expression was associated with abnormal non-complex karyotype, NPM1 wild-type status and TP53 mutation. CD2 also correlated with a lower complete remission (CR) rate (47.8% vs. 71.6%, p = 0.03). CyTdT and CD2 were associated with inferior 3-year event-free-survival (EFS) (5.3% vs. 33.5%, p = 0.003 and 17.4% vs. 33.1%, p = 0.02, respectively). CyTdT expression was also correlated with inferior relapse-free survival (27.3% vs. 48.8%, p = 0.04). In multivariable analyses CD2 positivity was an independent adverse factor for EFS (HR 1.72, p = 0.03). These results indicate a biological relevance of aberrant T-cell marker expression in AML and provide a rationale to further characterise the molecular origin in T-lineage-associated AML.

FINDER: A Fluidly Confined CRISPR-Based DNA Reporter on Living Cell Membranes for Rapid and Sensitive Cancer Cell Identification

The accurate, rapid, and sensitive identification of cancer cells in complex physiological environments is significant in biological studies, personalized medicine, and biomedical engineering. Inspired by the naturally confined enzymes on fluid cell membranes, a fluidly confined CRISPR-based DNA reporter (FINDER) was developed on living cell membranes, which was successfully applied for rapid and sensitive cancer cell identification in clinical blood samples. Benefiting from the spatial confinement effect for improved local concentration, and membrane fluidity for higher collision efficiency, the activity of CRISPR-Cas12a was, for the first time, found to be significantly enhanced on living cell membranes. This new phenomenon was then combined with multiple aptamer-based DNA logic gate for cell recognition, thus a FINDER system capable of accurate, rapid and sensitive cancer cell identification was constructed. The FINDER rapidly identified target cells in only 20 min, and achieved over 80 % recognition efficiency with only 0.1 % of target cells presented in clinical blood samples, indicating its potential application in biological studies, personalized medicine, and biomedical engineering.

SET-CAN/NUP214 fusion gene in leukemia: general features and clinical advances

SET-CAN/NUP214 fusion is a recurrent event commonly observed in adult male patients diagnosed with T-cell acute lymphoblastic leukemia (T-ALL) and has occasionally been reported in other diseases such as acute myeloid leukemia (AML), myeloid sarcoma (MS), acute undifferentiated leukemia (AUL), chronic myeloid leukemia (CML) and B-cell acute lymphoblastic leukemia (B-ALL). This fusion gene is derived from chromosome del(9)(q34.11;q34.13) or t(9;9)(q34;q34) and may have an inhibitory effect on primitive progenitor differentiation. The prognosis of the reported patients is varied, with these patients often show resistance to chemotherapy regimens that include high doses of glucocorticoids. The optional treatment has not been determined, more cases need to be accumulated and evaluated. The scope of this review is to summarize the general features and prognostic significance in leukemia associated with the SET-CAN/NUP214 fusion gene and to discuss the methods of detection and treatment, aiming at providing some useful references for relevant researchers in the field of blood tumor.

Targeted CD7 CAR T-cells for treatment of T-Lymphocyte leukemia and lymphoma and acute myeloid leukemia: recent advances

The high expression of CD7 targets in T-cell acute lymphoblastic leukemia (T-ALL) and T-lymphoma has attracted considerable attention from researchers. However, because CD7 chimeric antigen receptor (CAR) T-cells undergo fratricide, CD7 CAR T-cells develop an exhaustion phenotype that impairs the effect of CAR T-cells. There have been significant breakthroughs in CD7-targeted CAR T-cell therapy in the past few years. The advent of gene editing, protein blockers, and other approaches has effectively overcome the adverse effects of conventional methods of CD7 CAR T-cells. This review, in conjunction with recent advances in the 64th annual meeting of the American Society of Hematology (ASH), provides a summary of the meaningful achievements in CD7 CAR T-cell generations and clinical trials over the last few years.

Differential effects of recombinant human thrombopoietin on clinical outcomes in CD7-positive and CD7-negative acute myeloid leukaemia

To investigate the effect of recombinant human thrombopoietin (rhTPO) application on the clinical outcomes of CD7-positive acute myeloid leukaemia (CD7 + AML) patients following chemotherapy, we retrospectively studied 159 newly diagnosed non-M3 AML patients. Patients were divided into the following four groups according to the expression of CD7 in AML blasts and the use of rhTPO after chemotherapy: the CD7 + rhTPO group (n = 41), the CD7 + non-rhTPO group (n = 42), the CD7 negative (CD7-) rhTPO group (n = 37), and the CD7- non-rhTPO group (n = 39). The complete remission rate was higher in the CD7 + rhTPO group than in the CD7 + non-rhTPO group. Importantly, patients in the CD7 + rhTPO group had significantly higher 3-year overall survival (OS) rates and event-free survival (EFS) rates than those in the CD7 + non-rhTPO group, whereas they did not differ statistically between the CD7- rhTPO and CD7- non-rhTPO groups. In addition, multivariate analysis showed that rhTPO was an independent prognostic factor for OS and EFS in CD7 + AML. In conclusion, rhTPO led to better clinical outcomes for patients with CD7 + AML, while it had no significant effect on those with CD7- AML.

Synthesis of an Anti-CD7 Recombinant Immunotoxin Based on PE24 in CHO and E. coli Cell-Free Systems

Recombinant immunotoxins (RITs) are an effective class of agents for targeted therapy in cancer treatment. In this article, we demonstrate the straight-forward production and testing of an anti-CD7 RIT based on PE24 in a prokaryotic and a eukaryotic cell-free system. The prokaryotic cell-free system was derived from Escherichia coli BL21 StarTM (DE3) cells transformed with a plasmid encoding the chaperones groEL/groES. The eukaryotic cell-free system was prepared from Chinese hamster ovary (CHO) cells that leave intact endoplasmic reticulum-derived microsomes in the cell-free reaction mix from which the RIT was extracted. The investigated RIT was built by fusing an anti-CD7 single-chain variable fragment (scFv) with the toxin domain PE24, a shortened variant of Pseudomonas Exotoxin A. The RIT was produced in both cell-free systems and tested for antigen binding against CD7 and cell killing on CD7-positive Jurkat, HSB-2, and ALL-SIL cells. CD7-positive cells were effectively killed by the anti-CD7 scFv-PE24 RIT with an IC50 value of 15 pM to 40 pM for CHO and 42 pM to 156 pM for E. coli cell-free-produced RIT. CD7-negative Raji cells were unaffected by the RIT. Toxin and antibody domain alone did not show cytotoxic effects on either CD7-positive or CD7-negative cells. To our knowledge, this report describes the production of an active RIT in E. coli and CHO cell-free systems for the first time. We provide the proof-of-concept that cell-free protein synthesis allows for on-demand testing of antibody−toxin conjugate activity in a time-efficient workflow without cell lysis or purification required.

Genetically modified CD7-targeting allogeneic CAR-T cell therapy with enhanced efficacy for relapsed/refractory CD7-positive hematological malignancies: a phase I clinical study

Chimeric antigen receptor (CAR)-T cell therapy against T cell malignancies faces major challenges including fratricide between CAR-T cells and product contamination from the blasts. Allogeneic CAR-T cells, generated from healthy donor T cells, can provide ready-to-use, blast-free therapeutic products, but their application could be complicated by graft-versus-host disease (GvHD) and host rejection. Here we developed healthy donor-derived, CD7-targeting CAR-T cells (RD13-01) with genetic modifications to resist fratricide, GvHD and allogeneic rejection, as well as to potentiate antitumor function. A phase I clinical trial (NCT04538599) was conducted with twelve patients recruited (eleven with T cell leukemia/lymphoma, and one with CD7-expressing acute myeloid leukemia). All patients achieved pre-set end points and eleven proceeded to efficacy evaluation. No dose-limiting toxicity, GvHD, immune effector cell-associated neurotoxicity or severe cytokine release syndrome (grade ≥ 3) were observed. 28 days post infusion, 81.8% of patients (9/11) showed objective responses and the complete response rate was 63.6% (7/11, including the patient with AML). 3 of the responding patients were bridged to allogeneic hematopoietic stem cell transplantation. With a median follow-up of 10.5 months, 4 patients remained in complete remission. Cytomegalovirus (CMV) and/or Epstein-Barr virus (EBV) reactivation was observed in several patients, and one died from EBV-associated diffuse large B-cell lymphoma (DLBCL). Expansion of CD7-negative normal T cells was detected post infusion. In summary, we present the first report of a Phase I clinical trial using healthy donor-derived CD7-targeting allogeneic CAR-T cells to treat CD7+ hematological malignancies. Our results demonstrated the encouraging safety and efficacy profiles of the RD13-01 allogeneic CAR-T cells for CD7+ tumors.

CD7-directed CAR T-cell therapy: a potential immunotherapy strategy for relapsed/refractory acute myeloid leukemia

Relapsed/refractory acute myeloid leukemia (AML) patients generally have a dismal prognosis and the treatment remains challenging. Due to the expression of CD7 on 30% AML and not on normal myeloid and erythroid cells, CD7 is an attractive target for immunotherapy of AML. CD7-targeted CAR T-cells had demonstrated encouraging efficacy in xenograft models of AML. We report here on the use of autologous CD7 CAR T-cells in the treatment of a relapsed/refractory AML patient with complex karyotype, TP53 deletion, FLT3-ITD mutation, and SKAP2-RUNX1 fusion gene. Before the CAR T-cell therapy, the patient achieved partial remission with IA regimen and attained complete remission after reinduction therapy (decitabine and venentoclax). Relapse occurred after consolidation (CLAG regimen). Then she failed CLIA regimen combined with venetoclax and exhibited resistance to FLT3 inhibitors. Bone marrow showed 20% blasts (CD7+ 95.6%). A total dose of 5 × 10⁶/kg CD7 CAR T-cells was administered after the decitabine +FC regimen. Seventeen days after CAR T-cells infusion, she achieved morphologic leukemia-free state. The patient developed grade 3 cytokine release syndrome. No severe organ toxicity or immune effector cell-associated neurotoxicity syndrome was observed. In summary, the autologous CD7 CAR T-cell therapy could be considered a potential approach for AML with CD7 expression (NCT04762485).

Trial registration Clinical Trials.gov, NCT04762485. Registered on February 21, 2021, prospectively registered

Coexistence of Trisomy 8 and 13 in a Newly Diagnosed Patient With Diffuse Large B Cell Non-Hodgkin Lymphoma and Acute Myeloid Leukemia Secondary to Primary Myelofibrosis

Concomitant diagnosis of non-Hodgkin lymphoma (NHL) and acute myeloid leukemia secondary to chronic myeloproliferative neoplasms (MPNs) is rarely reported. Patients with MPNs may have a second neoplasm, and the risk of lymphoid line neoplasms is 2.5-3.5 times for lymphoid line neoplasms. The explanation for this association is the genetic instability of hematopoietic progenitors in MPNs. An 80-year-old Caucasian man, with many comorbidities, presents for physical asthenia, sweating. The right inguinal adenopathy was known one month before the examination. The patient was diagnosed concomitantly with diffuse large B cell lymphoma (DLBCL) and acute myeloid leukemia (AML) secondary to primary myelofibrosis (PMF) and presented trisomy 8, trisomy 13, and triple-negative PMF status. The patient initially received two well-tolerated R mini CHOP series. This type of treatment was selected to treat DLBCL for one unfit patient for intensive chemotherapy due to his age and comorbidities. R mini CHOP administration was followed by severe aplasia that lasted approximately two weeks followed by severe thrombocytosis that reached 4000 x109/L, and Thromboreductin recommendation was mandatory. The result of the treatment was a partial response but with severe adverse events like neutropenia G4, due to the delay of the treatment the patient lost the response. It was mandatory to select another treatment line and the chosen was venetoclax; it was selected for the simultaneous treatment of DLBCL and the underlying AML. It was obtained a significant reduction in the size of the inguinal lymph node block in two weeks of treatment. Severe neutropenia was diagnosed and complicated with sepsis. The evolution is unfavorable with the installation of multiple organ dysfunction. The presence of a complex karyotype (trisomy 8, trisomy 13) in a patient with myeloid metaplasia with triple-negative PMF was associated with blast transformation and severe thrombocytosis. The patient was diagnosed concomitantly with DLBCL, making the therapeutic decision difficult. Venetoclax has been shown to be useful in the treatment of DLBCL but has been associated with severe neutropenia, which has led to infectious complications.

MRD abnormal expression predict poor outcomes for refractory or relapsed acute myeloid leukemia after allogeneic hematopoietic stem cell transplantation

We retrospectively analyzed data from 197 patients with refractory or relapsed acute myeloid leukemia (r/rAML) who underwent allo‐HCT between January 2013 and February 2020 in our center (patients with promyelocytic leukemia were excluded). Of all patients, 86 achieved a complete morphological remission (CR) before transplant, while 111 failed to do so (NR). In the CR group, 32 patients displayed minimal residual disease (MRD‐positive). According to their immunophenotype pre‐HCT, we divided the MRD‐positive group and NR group into three subgroups: MRD 0+ group (without any antigen abnormal expression of CD7+, CD56+, CD38−, or HLA‐DR−) 28 patients, MRD 1+ group (with one abnormal antigen expression of CD7+, CD56+, CD38−, or HLA‐DR−) 63 patients, MRD 2+ group (with two or more abnormal antigens expression of CD7+, CD56+, CD38‐, or HLA‐DR‐) 52 patients. 3‐year estimates of disease‐free survival (DFS) for MRD 0+, MRD 1+ and MRD 2+ patients were 59.5 ± 9.5%, 29.9 ± 6.1%, and 9.4 ± 5.1%, and 3‐year estimates of overall survival (OS) were 59.5 ± 9.5%, 34.5 ± 6.3%, and 14.5 ± 10.8%, respectively. Multivariate analysis adjusted for genetic risk, blast cell level, secondary disease, age, sex, and donor relationship pre‐HCT, the hazard ratios of abnormal expression of CD7+, CD56+, HLA‐DR−, and CD38^‐ were 6.69 (range 2.08–21.52; p = 0.001) for DFS, 2.24 (range 1.21–4.14; p = 0.010) for OS, and 7.18 (range 2.23–23.10; p = 0.001) for relapse compared with CD7−, CD56−, HLA‐DR+, and CD38+ patients. Our finding suggested that abnormal expression of CD7+, CD56+, HLA‐DR−, and CD38− is associated with poor outcomes, and the more number of abnormal antigens expression predict worse outcomes.

Prognostic value of lymphoid marker CD7 expression in acute myeloid leukemia patients undergoing allogeneic hematopoietic cell transplantation in first morphological complete remission

Although defined as a lymphoid surface marker, CD7 is aberrantly expressed on a subtype of acute myeloid leukemia cells and appears to be associated with an inferior response to chemotherapy. Allogeneic hematopoietic cell transplantation (allo-HCT) is a potentially curative modality but no data has been reported in CD7-positive AML patients. We performed a retrospective analysis involving 141 AML patients who underwent allo-HCT in first morphological complete remission (CR1). The results showed that CD7-positive AML patients had a poor 2-year overall survival (64.5% vs 82.0%, P = 0.040), relapse-free survival (RFS) (56.5% vs 79.4%, P = 0.005), and higher cumulative incidence of relapse (27.0% vs 9.7%, P = 0.003) post-HCT. In addition, expression of CD7 was related to RAS and RUNX1 mutation, and high residual disease level pre-HCT. Multivariate analyses showed CD7 expression at diagnosis was an independent risk factor for RFS (P = 0.016, HR = 0.418) and relapse (P = 0.014, HR = 0.307). We concluded that for AML patients in CR1, CD7 is a negative predictor for allo-transplant outcomes.

[Analysis of the clinical characteristics of 24 cases of hematological malignancies with SET-NUP214 fusion gene]

Objective: To investigate the expression of SET-NUP214 fusion gene in hematological malignancies and to analyze its related clinical biological characteristics. Methods: The clinical data of 24 patients with SET-NUP214 fusion gene-positive hematological malignancies were retrospectively analyzed, and the Kaplan-Meier method was used for survival analysis. Results: Among the 24 patients with SET-NUP214 fusion gene, 15 cases of acute lymphoblastic leukemia (ALL) (13 cases of T-ALL and 2 cases of B-ALL) , 7 cases of acute myeloid leukemia (AML) , and 2 cases of T/myeloid mixed acute leukemia have been identified. The immunophenotype of 13 cases of T-ALL was mainly characterized by CD3(+)CD2(-), 73.3% of ALL was characterized by myeloid marker expression, and 85.7% of AML was characterized by CD7 expression. Complete remission (CR) was achieved in 22 patients (91.7%) after induction chemotherapy. All 24 patients received allogeneic hematopoietic stem cell transplantation (HSCT) . With a median follow-up of 24 months, the 3-year relapse free survival (RFS) of AML and ALL was 85.7% and 33.3%, respectively (P=0.128) . Comparing 13 cases of SET-NUP214-positive and 62 cases of SET-NUP214-negative T-ALL, the CR rates of induction chemotherapy were 92.3% and 93.5% (P=0.445) , and the 4-week CR rates of induction chemotherapy were 69.2% and 72.6%, respectively (P=0.187) ; the differences were not statistically significant. After HSCT, the 3-year RFS of SET-NUP214(+)T-ALL and SET-NUP214(-)T-ALL was 38.5% and 66.4%, respectively (P=0.028) , and the difference was statistically significant. Conclusion: The SET-NUP214 fusion gene is mainly detected in T cell-derived hematological malignancies, and the prognosis of SET-NUP214 positive T-ALL is relatively poor.

Adaptive immunity-related gene expression profile is correlated with clinical phenotype in patients with acute myeloid leukemia

Background

Acute myeloid leukemia (AML) is a common and lethal hematopoietic malignancy that is highly dependent on the immune microenvironment. However, light has yet to be shed on the landscape of adaptive immunity-related genes. This work aimed to uncover the novel molecular events in AML and potential therapeutic strategies for AML treatment.

Methods

For the current research, the transcriptional information of 732 genes that participate in adaptive immunity was collected from 173 patients with AML, and the patients were grouped into different cohorts based on the different expression patterns. The correlations between gene expression and clinical characteristics, including prognosis, were studied.

Results

According to the notably different expressions of adaptive immunity-related genes, the 173 patients were divided into 2 clusters and 3 subclusters. No significant differences in overall survival (OS) or progression-free survival (PFS) were detected between the clusters or subclusters. There were obvious discrepancies found in age, peripheral blood (PB) blast percentage, and French-American-British (FAB) classification between each cluster or subcluster. The patients in cluster 1 were older and more of them had M5 type; the patients in cluster 2 were younger and more of them had M2 type. Further, 81 genes were significantly correlated with age and 101 genes were significantly correlated with PB blast percentage. Comparison of the prognosis between each FAB type revealed that patients with M3 type displayed the most favorable OS and PFS. Among the differentially expressed genes (DEGs), CLEC2B expression was much lower in M2 patients than in patients with other types (P<0.001), and its high expression indicated a worse outcome (12.4 vs. 46.5 months of OS).

Conclusions

This study has uncovered the expression profile of adaptive immunity-related genes in AML. The different gene expression patterns are not associated with survival, but are significantly correlated the FAB types. CLEC2B expression is low in patients with M2 type and is negatively correlated with prognosis, thus revealing a potential therapeutic target for AML.

Lymphoid markers predict prognosis of pediatric and adolescent acute myeloid leukemia

Acute Myeloid Leukemia (AML) is a complex and highly aggressive disease. To characterize the prognostic factors of pediatric patients with AML relapse, a retrospective cohort study was performed to collect data from children and adolescents, at a hematological oncology reference center, over 11 years. We selected 51 cases of the disease, diagnosed and treated uniformly, divided into two groups: with complete remission (n = 33; 65 %) and with relapse (n = 18; 35 %). The groups were homogeneous concerning demographic characteristics and hematological parameters at diagnosis. AML M3 was the most common subtype (n = 19; 37 %) and was associated with a good prognosis. The highest rate of relapse was with AML M0 (n = 3 of 5 patients; 60 %). The most predominant gene mutation, FLT3-ITD, did not influence the prognosis in our study. The complete remission group presented a higher mean frequency of positive cells for the granulocytic marker CD13a at diagnosis. In cases with AML relapse, CD36, CD4, CD7, and CD22 were the most expressed markers. Increase incidence of recurrence was associated with CD7 (HR 1.035; p = 0.003), CD4 (HR 1.032, p = 0.001) and CD22 (HR 1.042; p = 0.049). Our results highlight the importance of analyzing immunophenotypic markers to help predict the outcome of AML in children and adolescents.

[Expression of CD7 and its correlation with prognosis in patients with NK/T-cell lymphoma]

Objective: To analysis the expression of CD7 in NK/T-cell lymphoma as well as study the correlations between CD7 and clinical survival and prognosis. Methods: The clinical and pathological indicators of 112 NKTCL patients who were admitted to or consulted at the First Affiliated Hospital of Zhengzhou University between May 2008 and December 2019 were analyzed retrospectively. The CD7 expression in the tumor tissues was detected using immunohistochemistry staining, and the influence of CD7 expression on the survival and prognosis in the patients was analyzed. Results: The CD7 expression rate was 84.82% in 112 NKTCL patients, and its expression was not influenced by sex, age, and the primary site. An analysis of the complete clinical data of 72 patients showed that the CD7 expression was significantly correlated with the PINK score, tumor metastasis, and peripheral blood EBV-DNA level. However, the Ann Arbor stage, bone marrow involvement, B symptoms, IPI/aaIPI score, Ki-67, EBER, TIA-1, Granzyme B, LDH, and β(2)-MG were not associated with the CD7 expression. The 1-year, 3-year, and 5-year overall survival (OS) rates of the 72 patients were 81.2%, 61.8%, and 58.8%, respectively, and the progression-free survival (PFS) rates were 53.5%, 29.4%, and 24.0%, respectively. The median overall survival (median-OS, mOS) was 81 mon, and the median progression-free survival (median-PFS, mPFS) was 14 mon. The 3-year OS rates in the CD7-positive group and the CD7-negative group were 58.1% and 83.9%, respectively, (P>0.05) . The 3-year PFS rates were 21.7% and 51.9%, respectively (P<0.05) . The univariate analysis showed that age, primary tumor site, Ann Arbor stage, IPI/aaIPI score, PINK score, LDH, β(2)-microglobulin, EBV-DNA, Ki-67, and CD7 influenced patient prognosis. The multivariate analysis showed that Ann Arbor stage and CD7 were independent prognostic factors for PFS, while PINK score and Ki-67 were independent prognostic factors for OS. Conclusions: The expression rate of CD7 in NKTCL was high and was closely related to poor patient prognosis. The patients with high levels of EBV-DNA, metastatic disease, or high PINK score were more likely to express CD7.

Combination of FLT3-ITD Allelic Ratio, NPM1 Mutation, and Immunophenotypic Markers to Modulate Outcome Prediction in Patients with Normal Karyotype Acute Myelogenous Leukemia Undergoing Hematopoietic Stem Cell Transplantation

NPM1 mutation status and the allelic ratio (AR) of FLT3-internal tandem duplication (FLT3-ITD) are routinely tested for disease risk stratification in patients with normal karyotype (NK) acute myelogenous leukemia (AML); however, the predictive impact of immunophenotypic markers on different NPM1/FLT3 genotypes remains unclear. We performed a retrospective analysis of 423 patients with NK-AML subclassified into groups based on NPM1/FLT3 genotype. Allogeneic hematopoietic stem cell transplantation (HSCT) was performed in 124 of 423 patients (29%) and was significantly associated with longer event-free survival (EFS) and overall survival (OS), except for patients with the favorable genotype, defined as mutated NPM1 (NPM1^mut) combined with normal FLT3 status (FLT3-ITD^neg) or FLT3-ITD AR <.5 (FLT3-ITD^low). A subset of AML patients bearing the favorable NPM1^mut/FLT3-ITD^neg/low genotype share similar outcomes with AML patients who have the intermediate FLT3/NPM1 genotype defined by normal NPM1 (NPM1^wt) and FLT3-ITD^neg/low. In these individuals, the lack of CD13 expression (CD13^neg) was associated with shorter EFS (P = .041) and OS (P = .017). CD13^neg was an independent predictor for shorter OS (hazard ratio, 1.985; P = .028).

ERK Activity in Immature Leukemic Cells Drives Clonal Selection during Induction Therapy for Acute Myeloid Leukemia

Selection of resistant clones following intensive chemotherapy is a common obstacle for cure in many cancers, particularly in acute myeloid leukemia (AML). In AML, clone-specific sensitivity to chemotherapy varies even within the same patient. Multiple mutations and genetic aberrations are associated with clones surviving chemotherapy. The current study explored the role of activated signaling pathways in chemoresistance as a function of cell maturation, reflected by CD34 expression. In-vitro, Kasumi-1 leukemic cell line, sorted by CD34 expression, showed increased apoptosis only in the CD34⁻ subpopulation after exposure to cytosine arabinoside (Ara-C) or daunorubicin. The resistant CD34⁺ subset demonstrated higher expression of ERK1/2 and BCL-2 proteins than CD34⁻ cells. MEK1/2 inhibition elevated Ara-C ability to induce apoptosis in CD34⁺ cells, suggesting that MEK1/2-ERK1/2 is surviving signaling, which correlates to cell maturation levels and plays a role in chemoresistance. Deep sequencing of sorted CD34^+/− populations, both derived from the same patient samples, demonstrated various subclonal distribution of NPM1, DNMT3A and FLT3-ITD mutations. Interestingly, in these samples, p-ERK levels and apoptosis rates following chemotherapy exposure significantly differed between CD34^+/− populations. Hence, clones may be selected due to their ability to escape apoptosis rather than a direct effect of chemotherapy on a specific mutated clone.

Harnessing T Cells to Target Pediatric Acute Myeloid Leukemia: CARs, BiTEs, and Beyond

Outcomes for pediatric patients with acute myeloid leukemia (AML) remain poor, highlighting the need for improved targeted therapies. Building on the success of CD19-directed immune therapy for acute lymphocytic leukemia (ALL), efforts are ongoing to develop similar strategies for AML. Identifying target antigens for AML is challenging because of the high expression overlap in hematopoietic cells and normal tissues. Despite this, CD123 and CD33 antigen targeted therapies, among others, have emerged as promising candidates. In this review we focus on AML-specific T cell engaging bispecific antibodies and chimeric antigen receptor (CAR) T cells. We review antigens being explored for T cell-based immunotherapy in AML, describe the landscape of clinical trials upcoming for bispecific antibodies and CAR T cells, and highlight strategies to overcome additional challenges facing translation of T cell-based immunotherapy for AML.

Applications and efficiency of flow cytometry for leukemia diagnostics

Introduction: Multiparametric flow cytometry immunophenotype (MFCI) plays a crucial role in the diagnosis of acute leukemia (AL). Through the comprehensive assessment of surface and intracellular antigens expressed by blasts, MFCI permits to distinguish myeloid or B/T lymphoid AL, or AL of ambiguous lineages. By means of MFCI, the blasts can be characterized in bone marrow, peripheral blood, and body fluids, such as cerebrospinal fluid.Area covered: This review discusses how MFCI is currently applied in the diagnostic evaluation of AL; it also focuses on 'peculiar' issues such as the role of MFCI for the diagnosis of central nervous system leukemic involvement.Expert commentary: Despite the improved knowledge about the biology of AL, MFCI remains a fundamental tool to make a prompt and accurate diagnosis. MFCI also provides prognostic information for some antigens are associated with specific cytogenetic/genetic abnormalities and, recently, it became a powerful tool to evaluate the quality and depth of response (the so called 'measurable residual disease'). Its role as an efficient detector of residual disease paved the way to the investigation of tissues other than bone marrow and peripheral blood, demonstrating that even small amounts of AL appear to have a prognostic impact and may require personalized intervention.

CD7 CAR T Cells for the Therapy of Acute Myeloid Leukemia

Chimeric antigen receptor (CAR) T cell therapy for the treatment of acute myeloid leukemia (AML) has the risk of toxicity to normal myeloid cells. CD7 is expressed by the leukemic blasts and malignant progenitor cells of approximately 30% of AML patients but is absent on normal myeloid and erythroid cells. Since CD7 expression by malignant blasts is also linked with chemoresistance and poor outcomes, targeting this antigen may be beneficial for this subset of AML patients. Here, we show that expression of a CD7-directed CAR in CD7 gene-edited (CD7^KO) T cells effectively eliminates CD7⁺ AML cell lines, primary CD7⁺ AML, and colony-forming cells but spares myeloid and erythroid progenitor cells and their progeny. In a xenograft model, CD7 CAR T cells protect mice against systemic leukemia, prolonging survival. Our results support the feasibility of using CD7^KO CD7 CAR T cells for the non-myeloablative treatment of CD7⁺ AML.

The clinical importance of CD4+ CD7- in human diseases

The CD7 antigen is a member of the immunoglobulin superfamily that expresses on the surface of all thymocytes, a majority of mature T cells, and also natural killer cells. Interestingly, under physiological and different pathological conditions, the loss of CD7 antigen occurred in the subset of CD4⁺ memory T cells. Various functions have been proposed for CD7, including its role in the activation and intercellular adhesiveness of T cells. Several studies indicate that the number of CD4⁺ CD7^- T cells increases in diseases such as chronic inflammation and T-cell malignancies, these being skin inflammatory lesions. Therefore, this can be useful for the diagnosis of cancer cells, especially with reference to blood origin, treatment monitoring, and establishment of new therapies. Therefore, a comprehensive review could be useful to increase our knowledge about the clinical importance of these cells in human disease.

CD7 is expressed on a subset of normal CD34-positive myeloid precursors

OBJECTIVE

To improve monitoring of myeloid neoplasms by flow cytometry-based minimal residual disease (MRD) analysis, we analyzed the significance of leukemia-associated immunophenotype (LAIP) markers in 44 patients.

METHODS

In a pilot study cohort, peripheral blood or bone marrow samples from 13 patients with myeloid neoplasms and one case of B lymphoblastic leukemia in complete hematologic remission after allogeneic bone marrow or stem cell transplantation were subjected to selection for leukemia-specific phenotypes by fluorescence-activated cell sorting using individual marker combinations, followed by PCR-based chimerism analysis.

RESULTS

The feasibility of this method could be demonstrated, with selection being successful in 12 cases, including two cases where mixed chimerism was found exclusively in sorted cells. Interestingly, four specimens displayed full donor chimerism in cells expressing the presumably aberrant combination CD34⁺ /CD7⁺ . Further analyses, including assessment of an independent cohort of 25 patients not affected by neoplastic bone marrow infiltration, revealed that normal myeloid precursors usually include a population coexpressing CD34, CD13, CD33, and CD7.

CONCLUSION

We conclude that the combination CD34⁺ /CD7⁺ might not be suitable as an LAIP for MRD diagnostics and that a subset of normal myeloid precursors in the bone marrow expresses CD7.

The putative anti-leukemic effects of anti-thymocyte globulins in patients with CD7-positive acute myeloid leukemia

Polyclonal anti-thymocyte globulins (ATGs) are widely used in allogeneic stem cell transplantation (allo-SCT) for GvHD prophylaxis. ATGs exerted anti-tumor effects in in vitro experiments, but in vivo studies are lacking. We experienced a case of relapsed AML with cells positive for CD7 who underwent haploidentical SCT and unexpectedly achieved a significant reduction of AML cells in the peripheral blood after receiving ATGs before the administration of other drugs in the conditioning regimen. This patient achieved long-term survival after haploidentical SCT. To assess the impact of ATGs on clinical outcomes in patients with AML, we performed a retrospective analysis of allo-SCT for relapsed/refractory AML and divided 132 patients into four groups according to the expression of CD7 in AML cells and use of ATGs as part of the conditioning regimen, as follows: CD7-positive ATG group (n = 15), CD7-positive no-ATG group (n = 32), CD7-negative ATG group (n = 19), and CD7-negative no-ATG group (n = 66). The overall survival rates in the CD7-positive ATG group were significantly higher than those in the CD7-positive no-ATG group, whereas these rates did not differ statistically between the CD7-negative ATG and CD7-negative no-ATG groups. Our results indicate a possible anti-leukemic effect of ATGs against CD7-positive AML in humans.

A comprehensive overview of lncRNA annotation resources

Long noncoding RNAs (lncRNAs) are emerging as a class of important regulators participating in various biological functions and disease processes. With the widespread application of next-generation sequencing technologies, large numbers of lncRNAs have been identified, producing plenty of lncRNA annotation resources in different contexts. However, at present, we lack a comprehensive overview of these lncRNA annotation resources. In this study, we reviewed 24 currently available lncRNA annotation resources referring to > 205 000 lncRNAs in over 50 tissues and cell lines. We characterized these annotation resources from different aspects, including exon structure, expression, histone modification and function. We found many distinct properties among these annotation resources. Especially, these resources showed diverse chromatin signatures, remarkable tissue and cell type dependence and functional specificity. Our results suggested the incompleteness and complementarity of current lncRNA annotations and the necessity of integration of multiple resources to comprehensively characterize lncRNAs. Finally, we developed 'LNCat' (lncRNA atlas, freely available at http://biocc.hrbmu.edu.cn/LNCat/), a user-friendly database that provides a genome browser of lncRNA structures, visualization of different resources from multiple angles and download of different combinations of lncRNA annotations, and supports rapid exploration, comparison and integration of lncRNA annotation resources. Overall, our study provides a comprehensive comparison of numerous lncRNA annotations, and can facilitate understanding of lncRNAs in human disease.

A Leukemia-Associated CD34/CD123/CD25/CD99+ Immunophenotype Identifies FLT3-Mutated Clones in Acute Myeloid Leukemia

PURPOSE

We evaluated leukemia-associated immunophenotypes (LAIP) and their correlation with fms-like tyrosine kinase 3 (FLT3) and nucleophosmin (NPM1) gene mutational status in order to contribute a better identification of patients at highest risk of relapse in acute myeloid leukemia (AML).

EXPERIMENTAL DESIGN

Bone marrow samples from 132 patients with AML were analyzed by nine-color multiparametric flow cytometry. We confirmed the presence of the mutation in diagnostic samples and in sorted cells by conventional RT-PCR and by patient-specific RQ-PCR.

RESULTS

Within the CD34(+) cell fraction, we identified a discrete population expressing high levels of the IL3 receptor α-chain (CD123) and MIC-2 (CD99) in combination with the IL2 receptor α-chain (CD25). The presence of this population positively correlated with the internal tandem duplications (ITD) mutation in the FLT3 gene (r = 0.71). Receiver operating characteristics showed that, within the CD34(+) cell fraction a percentage of CD123/CD99/CD25(+) cells ≥11.7% predicted FLT3-ITD mutations with a specificity and sensitivity of >90%. CD34/CD123/CD99/CD25(+) clones were also detectable at presentation in 3 patients with FLT3 wild-type/NPM1(+) AML who relapsed with FLT3-ITD/NPM1(+) AML. Quantitative real-time PCR designed at relapse for each FLT3-ITD in these three cases confirmed the presence of low copy numbers of the mutation in diagnostic samples.

CONCLUSIONS

Our results suggest that the CD34/CD25/CD123/CD99(+) LAIP is strictly associated with FLT3-ITD-positive cells.

CD7 promotes extramedullary involvement of the B-cell acute lymphoblastic leukemia line Tanoue by enhancing integrin β2-dependent cell adhesiveness

Extramedullary involvement (EMI) is a factor that defines prognosis of acute lymphoblastic leukemia; however, the molecular mechanism(s) remain elusive. Here, we show that CD7 promotes EMI of the human B-cell acute lymphoblastic leukemia cell line Tanoue. The Tanoue cell line expressing firefly luciferase, Luc-Tanoue, was transplanted into non-obese diabetic/severe combined immunodeficient mice, and cells infiltrated into the brain were cultured ex vivo. This process was repeated 4 times to obtain the highly invasive line Luc-Tanoue-F4. Comparison of the global gene expression signatures of Luc-Tanoue-F4 and Luc-Tanoue indicated that the CD7 gene showed the largest increase in expression among EMI-related genes in Luc-Tanoue-F4 cells. Overexpression of CD7 in Tanoue enhanced cell invasiveness. Among cell migration, proliferation, adhesion and protease activity, only cell adhesiveness showed enhancement in Luc-Tanoue-F4. Expression of the intracellular domain, but not the extracellular domain, of CD7 enhanced cell adhesiveness. Luc-Tanoue-F4 showed a higher level of integrin β2 expression; overexpression of CD7 induced the expression of integrin β2 in Luc-Tanoue. These results show that CD7 induces integrin β2 and enhances cell adhesiveness and invasiveness in Tanoue cells. This study highlights the role of the CD7/integrin β2 axis as a critical pathway in the process of EMI of human B-cell acute lymphoblastic leukemia.

Leukemia-associated aberrant immunophenotype in patients with acute myeloid leukemia: changes at refractory disease or first relapse and clinicopathological findings

INTRODUCTION

Multiparameter flow cytometry (MFC) is commonly used to detect minimal residual disease (MRD) during the course of chemotherapy or relapse. Only one study addressed the immunophenotypic changes in refractory disease. We studied changes in leukemia-associated aberrant immunophenotype (LAIP) in patients with refractory and relapsed acute myeloid leukemia (AML).

METHOD

We analyzed 47 patients (refractory = 22; relapsed = 25) by MFC, morphology, and cytogenetic studies.

RESULTS

Thirty-five patients (74%) showed variably changed LAIPs. The frequently altered LAIPs were lack of lineage-specific antigen and lineage infidelity. The most frequently changed marker was CD13, followed by CD33, CD56, CD7, CD4, and CD11b. Cytogenetic clonal evolution at persistence/relapse was observed in 15 patients (32%). Morphologically, three patients (6%) showed significant changes at relapse. Patients with refractory AML had a higher association with poor cytogenetic risk and classification of AML with myelodysplasia-related changes. Positive MRD at postinduction was of prognostic significance. Allogeneic stem cell transplant improved overall survival.

CONCLUSIONS

LAIP alterations in refractory/relapsed AMLs are common findings. Presence of persistent disease indicates a poor prognosis, regardless of cytogenetic risk or expression of CD7 or CD56. Discordance between cytogenetic and LAIP changes suggests that gross cytogenetic clonal evolution during disease progression only partly contributes to immunophenotypic instability.

CD34 expression predicts an adverse outcome in patients with NPM1-positive acute myeloid leukemia

Patients with acute myeloid leukemia (AML) harboring an NPM1 mutation exhibit a heterogeneous clinical outcome. Recent studies have shown that the absence of FLT3 internal tandem duplication (FLT3-ITD) mutation confers a favorable prognosis in NPM1-positive AML. However, the prognostic impact of immunophenotypes in this subgroup remains unclear. In this study, FLT3 mutation status and immunophenotypic profile of 85 NPM1-positive patients with de novo AML were retrospectively analyzed and correlated with their clinical features and survival outcomes. Univariate analysis detected 5 markers with prognostic relevance: older age (≥60 years), high white blood cell (WBC) count (>30 × 10(9)/L), FLT3-ITD, CD7, and CD34 expression. Multivariate analysis showed that high WBC count was the only independent predictor of a lower complete remission rate (P = .019). Older age (P = .035), high WBC count (P = .008), FLT3-ITD (P = .012), and CD34 expression (P = .006) were independent predictors of a shorter event-free survival (EFS). High WBC count (P = .014), FLT3-ITD (P = .005), and CD34 expression (P = .047) were independent predictors of a shorter overall survival (OS). Furthermore, based on FLT3-ITD status in NPM1 mutation-positive patients, we showed that both high WBC and CD34 expression conferred a poor EFS (P = .010 and P = .016, respectively) and OS (P = .032 and P = .001, respectively) in the FLT3-ITD-negative group, whereas high WBC predicted a poor EFS (P = .016) and OS (P = .027) in the FLT3-ITD-positive group. Our results confirm the prognostic value of assessing FLT3-ITD mutations in NPM1-positive AML and identify the adverse prognostic impact of high WBC and CD34 expression in this subgroup of AML.

Therapy-related acute lymphoblastic leukemia is more frequent than previously recognized and has a poor prognosis

BACKGROUND

Acute lymphoblastic leukemia (ALL) occurring in patients with a history of prior chemotherapy/radiotherapy exposure has been previously reported to be rare, accounting for <2.5% of ALL cases.

METHODS

All cases of adult ALL with a history of prior cytotoxic or radiation therapy at a leukemia referral center over a 13-year period were analyzed.

RESULTS

Twenty-three cases, representing 6.9% of all ALL cases, were identified. Of these, 17 (74%) had at least 1 high-risk feature; 8 (35%) had MLL rearrangements, and 4 were BCR-ABL(+) . MLL rearrangements were correlated with CD15 expression and absence of CD10, and also tended to have a shorter mean latency period and more prior topoisomerase II exposure. Twenty-one patients received induction therapy, and 18 (86%) achieved a complete response, 17 with 1 induction. Six patients have relapsed and died, and 4 others died of other complications, 2 of these postallogeneic stem cell transplantation. Median disease-free survival (DFS) and overall survival (OS) were 27 and 13.6 months, respectively, and 3-year DFS and OS were 37.1% and 37.6%, respectively.

CONCLUSIONS

The frequency of therapy-related ALL is higher than previously reported and has a poor prognosis, probably related to the high frequency of adverse risk features.

Review of the relevance of aberrant antigen expression by flow cytometry in myeloid neoplasms

This article reviews the use of aberrant antigen expression detected by flow cytometry in the diagnosis and clinical handling of acute myeloid leukaemia (AML) and the myelodysplastic syndromes (MDS). Such aberrancies offer a valuable tool for the proper classification of these myeloid malignancies according the World Health Organization 2008 classification. Aberrant antigen expression by flow cytometry is also important for prognostification. This review supports the view, that minimal residual disease detection methods that make use of such aberrancies should be part of the routine management of AML patients to guide therapy, but also suggests the introduction of flow cytometry in MDS for diagnosis and treatment decisions in the near future.

Expression of the leukemic prognostic marker CD7 is linked to epigenetic modifications in chronic myeloid leukemia

Background

Expression levels of the cell surface glycoprotein, CD7, and the serine protease, elastase 2 (ELA2), in the leukemic cells of patients with chronic myeloid leukemia (CML) have been associated with clinical outcome. However, little is known about the mechanisms that underlie the variable expression of these genes in the leukemic cells.

Results

To address this question, we compared the level of their expression with the DNA methylation and histone acetylation status of 5' sequences of both genes in leukemic cell lines and primitive (lin^-CD34⁺) leukemic cells from chronic phase CML patients. DNA methylation of the ELA2 gene promoter did not correlate with its expression pattern in lin^-CD34⁺ cells from chronic phase CML patient samples even though there was clear differential DNA methylation of this locus in ELA2-expressing and non-expressing cell lines. In contrast, we found a strong relation between CD7 expression and transcription-permissive chromatin modifications, both at the level of DNA methylation and histone acetylation with evidence of hypomethylation of the CD7 promoter region in the lin^-CD34⁺ cells from CML patients with high CD7 expression.

Conclusion

These findings indicate a link between epigenetic modifications and CD7 expression in primitive CML cells.

Cytoplasmic expression of nucleophosmin accurately predicts mutation in the nucleophosmin gene in patients with acute myeloid leukemia and normal karyotype

Mutations in the nucleophosmin (NPM1) exon 12 resulting in delocalization of NPM1 into the cytoplasm occur in 50% to 60% of acute myeloid leukemia cases with a normal karyotype (AML-NK). As recent studies suggest such patients have a favorable prognosis and there are discordant reports of the immunohistochemical detection of cytoplasmic NPM1 (NPMc+) for predicting NPM1 gene mutations, we correlated the immunohistochemical detection of NPMc+, NPM1 gene mutations, and prognosis in 57 cases of AML-NK. All 31 NPMc+ cases (54% of total) had NPM1 mutations, but none of the 26 nucleus-restricted (NPMc-) cases (46% of total) had NPM1 mutations (P < .0001). NPM1 mutations were correlated with FLT3-internal tandem duplication (ITD) (P = .0062), absence of CD34 (P = .0001), and absence of CD7 (P = .041). There was a favorable survival outcome in AML-NK cases that were NPM1 mutated and FLT3-ITD nonmutated. Our data confirm that cytoplasmic NPM1 immunoreactivity predicts NPM1 mutations and warrants inclusion in the routine diagnostic and prognostic workup of AML.

Bone marrow aspirate and biopsy: a pathologist's perspective. II. interpretation of the bone marrow aspirate and biopsy

Bone marrow examination has become increasingly important for the diagnosis and treatment of hematologic and other illnesses. Morphologic evaluation of the bone marrow aspirate and biopsy has recently been supplemented by increasingly sophisticated ancillary assays, including immunocytochemistry, cytogenetic analysis, flow cytometry, and molecular assays. With our rapidly expanding knowledge of the clinical and biologic diversity of leukemia and other hematologic neoplasms, and an increasing variety of therapeutic options, the bone marrow examination has became more critical for therapeutic monitoring and planning optimal therapy. Sensitive molecular techniques, in vitro drug sensitivity testing, and a number of other special assays are available to provide valuable data to assist these endeavors. Fortunately, improvements in bone marrow aspirate and needle technology has made the procurement of adequate specimens more reliable and efficient, while the use of conscious sedation has improved patient comfort. The procurement of bone marrow specimens was reviewed in the first part of this series. This paper specifically addresses the diagnostic interpretation of bone marrow specimens and the use of ancillary techniques.