Expression of CD56 is a risk factor for acute lymphocytic leukemia with central nervous system involvement in adults

Breast cancer exploits neural signaling pathways for bone-to-meninges metastasis

The molecular mechanisms that regulate breast cancer cell (BCC) metastasis and proliferation within the leptomeninges (LM) are poorly understood, which limits the development of effective therapies. In this work, we show that BCCs in mice can invade the LM by abluminal migration along blood vessels that connect vertebral or calvarial bone marrow and meninges, bypassing the blood-brain barrier. This process is dependent on BCC engagement with vascular basement membrane laminin through expression of the neuronal pathfinding molecule integrin α6. Once in the LM, BCCs colocalize with perivascular meningeal macrophages and induce their expression of the prosurvival neurotrophin glial-derived neurotrophic factor (GDNF). Intrathecal GDNF blockade, macrophage-specific GDNF ablation, or deletion of the GDNF receptor neural cell adhesion molecule (NCAM) from BCCs inhibits breast cancer growth within the LM. These data suggest integrin α6 and the GDNF signaling axis as new therapeutic targets against breast cancer LM metastasis.

Diagnosis and management of adult central nervous system leukemia

Central nervous system leukemia (CNSL) is a prominent infiltration reason for therapy failing in acute leukemia. Recurrence rates and the prognosis have alleviated with current prophylactic regimens. However, the accurate stratification of relapse risk and treatment regimens for relapsed or refractory patients remain clinical challenges yet to be solved. Recently, with hematopoietic stem cell transplantation (HSCT) and chimeric antigen receptor-T (CAR-T) cellular therapy showing encouraging effects in some CNSL patients, advances in treating CNSL have already been reported. The development of molecular targeted agents as well as antibody-based drugs will provide patients with more personalized treatment. This article summarized recent research developments about risk factors, diagnosis, prevention, and treatment in adults with CNSL.

Central Nervous System Involvement in Adults with Acute Leukemia: Diagnosis, Prevention, and Management

PURPOSE OF REVIEW

Recent treatment advances in both acute myeloid leukemia and acute lymphoblastic leukemia have drastically improved outcomes for these diseases, but central nervous system (CNS) relapses still occur. Treatment of CNS disease can be challenging due to the impermeability of the blood-brain barrier to many systemic therapies.

RECENT FINDINGS

The diagnosis of CNS leukemia relies on assessment of clinical symptoms, cerebrospinal fluid sampling for conventional cytology and/or flow cytometry, and neuroimaging. While treatment of CNS leukemia with systemic or intrathecal chemotherapy and/or radiation can be curative in some patients, these modalities can also lead to serious toxicities. In the modern era, prophylaxis with intrathecal chemotherapy is the most important strategy to prevent CNS relapses in high risk patients. Accurate risk stratification tools and the use of risk-adapted prophylactic therapy are imperative to improving the outcomes of patients with acute leukemias and preventing the development of CNS leukemia.

Metabolic Reprogramming and Cell Adhesion in Acute Leukemia Adaptation to the CNS Niche

Involvement of the Central Nervous System (CNS) in acute leukemia confers poor prognosis and lower overall survival. Existing CNS-directed therapies are associated with a significant risk of short- or long-term toxicities. Leukemic cells can metabolically adapt and survive in the microenvironment of the CNS. The supporting role of the CNS microenvironment in leukemia progression and dissemination has not received sufficient attention. Understanding the mechanism by which leukemic cells survive in the nutrient-poor and oxygen-deprived CNS microenvironment will lead to the development of more specific and less toxic therapies. Here, we review the current literature regarding the roles of metabolic reprogramming in leukemic cell adhesion and survival in the CNS.

A narrative review of central nervous system involvement in acute leukemias

Acute leukemias (both myeloid and lymphoblastic) are a group of diseases for which each year more successful therapies are implemented. However, in a subset of cases the overall survival (OS) is still exceptionally low due to the infiltration of leukemic cells in the central nervous system (CNS) and the subsequent formation of brain tumors. The CNS involvement is more common in acute lymphocytic leukemia (ALL), than in adult acute myeloid leukemia (AML), although the rates for the second case might be underestimated. The main reasons for CNS invasion are related to the expression of specific adhesion molecules (VLA-4, ICAM-1, VCAM, L-selectin, PECAM-1, CD18, LFA-1, CD58, CD44, CXCL12) by a subpopulation of leukemic cells, called “sticky cells” which have the ability to interact and adhere to endothelial cells. Moreover, the microenvironment becomes hypoxic and together with secretion of VEGF-A by ALL or AML cells the permeability of vasculature in the bone marrow increases, coupled with the disruption of blood brain barrier. There is a single subpopulation of leukemia cells, called leukemia stem cells (LSCs) that is able to resist in the new microenvironment due to its high adaptability. The LCSs enter into the arachnoid, migrate, and intensively proliferate in cerebrospinal fluid (CSF) and consequently infiltrate perivascular spaces and brain parenchyma. Moreover, the CNS is an immune privileged site that also protects leukemic cells from chemotherapy. CD56/NCAM is the most important surface molecule often overexpressed by leukemic stem cells that offers them the ability to infiltrate in the CNS. Although asymptomatic or with unspecific symptoms, CNS leukemia should be assessed in both AML/ALL patients, through a combination of flow cytometry and cytological analysis of CSF. Intrathecal therapy (ITT) is a preventive measure for CNS involvement in AML and ALL, still much research is needed in finding the appropriate target that would dramatically lower CNS involvement in acute leukemia.

Precursor B-lineage acute lymphoblastic leukemia patients with aberrant natural killer cell and T cell - lineage antigen expression: experience from a tertiary cancer care center

Introduction

Flow cytometric immunophenotyping (FCI) plays a major role in diagnosing hematologic malignancies. In patients diagnosed with precursor B-lineage acute lymphoblastic leukemia (B-ALL), expression of certain non-lineage/cross lineage antigens is of prognostic and cytogenetic relevance. There is a paucity of studies that have comprehensively analyzed the clinical and laboratory profiles of B-ALL patients showing aberrant T/natural killer (NK) cell antigen expression.

Materials and methods

This is a prospective study where 152 consecutive B-ALL patients were analyzed for aberrant expression of T/NK cell antigens (CD1a, CD5, CD4, CD7, CD8 and CD56) by FCI. The clinical and laboratory profile of these T/NK-cell antigen-expressing B-ALL patients was statistically analyzed against conventional B-ALL patients.

Results

In our B-ALL cohort, CD5, CD7 and CD56 expression were observed in one, six and nine patients, respectively. CD56-expressing B-ALL patients were predominantly children (89%) and presented as standard clinical risk (p = 0.010) disease with frequent ETV6-RUNX1 fusion (p = 0.021) positivity. On the contrary, CD7-expressing B-ALL patients were adolescent-young adult/adult-age skewed (83%) and had an adverse cytogenetic profile (p = 0.001), especially for the frequent presence of BCR-ABL1 fusion (p = 0.004) and KMT2A rearrangement (p = 0.045). CD7-expressing B-ALL patients had inferior event-free survival (p = 0.040) than their CD56-expressing counterparts, but there was no significant difference in the overall survival (p = 0.317).

Conclusion

In comparison to conventional B-ALL patients, there are significant differences in the age, cytogenetic profile and event-free survival of T/NK-cell antigen-expressing B-ALL patients.

Clinical Effect of CD25 on the Prognosis of Diffuse Large B Cell Lymphoma with Secondary Central Nervous System Relapse

In the present study, we investigated the effects of immunophenotyping on prognosis of diffuse large B cell lymphoma (DLBCL) with central nervous system (CNS) relapse treated with rituximab-CHOP (R-CHOP). CNS relapse occurred in 9.5% of DLBCL patients. At the diagnosis of DLBCL, CD25 was detected in 14.3% of cases. CD25 positivity correlated with an advanced stage, higher R-IPI, higher CNS-IPI, the presence of B symptoms, the presence of extranodal involvement >1, and bone involvement. Moreover CNS relapse was more frequently observed in patients with CD25+ than in those with CD25-. The univariate analysis showed that an advanced stage, high-risk R-IPI, high-risk CNS-IPI, bone involvement, and CD25+ were associated with shorter overall survival (OS). The multivariate analysis confirmed that CD25+ and high-risk CNS-IPI were independent adverse prognostic factors for shorter OS. A Kaplan-Meier analysis revealed the potential of CD25+ as a prognostic factor in patients with CNS relapse and that it correlated with shorter survival. The present results showed that the expression of CD25 in DLBCL patients with CNS relapse was associated with the patient prognosis independent other prognostic factors. The establishment of a treatment strategy for CNS relapse patients with CD25+ DLBCL cells is needed to improve poor outcomes.

Prognostic impact of CD200 and CD56 expression in pediatric B-cell acute lymphoblastic leukemia patients

This study aimed to determine the prognostic impact of CD200 and CD56 expression in pediatric B cell acute lymphoblastic leukemia (B-ALL) patients, both of which have been implicated in immune tolerance and previously suggested as independent risk factors. CD200 has a central role in immune tolerance that protects stem cells and other critical tissues from immune damage. The expression of CD200/CD56 in leukemic blasts were assessed in leukemic blasts before chemotherapy in 43 bone marrow (BM) and/or peripheral blood (PB) samples by flow cytometry. Twenty eight of 43 B-ALL cases (65%) showed CD200 positive expression, 5 of 43 cases (11.6%) showed CD56 expression, and only 2 patients (4.7%) expressed both CD200 and CD56. Patients with CD200⁺ and CD56⁺ were significantly associated with lower platelet count; less tendency for induction of remission response as compared to negative ones (p = .01 for both). The overall survival (OS) and DFS were significantly shorter in CD200⁺ and CD56⁺ cases as compared to those with CD200^- and CD56^- expression. In conclusion, CD200 and/or CD56 positive expression in B-ALL at diagnosis suggest a poor prognosis and may be associated with biological aggressiveness.