CD5-positive B-cell acute lymphoblastic leukemia

B-Lymphoblastic Leukemia With Aberrant CD5 Expression

OBJECTIVES

B-acute lymphoblastic leukemia (B-ALL) is a neoplasm of precursor lymphoid cells committed to the B-lineage. Expression of CD5 is rare in B-ALL.

METHODS

We studied the clinicopathologic, immunophenotypic, and molecular genetic features of 10 cases of B-ALL with aberrant CD5 expression, and compared with CD5-B-ALL.

RESULTS

B-ALL with aberrant CD5 expression is rare and predominantly affects men. Patients with CD5+ B-ALL had shorter median overall survival (21 vs 45 months, P = .0003). Expression of CD5 imposed a challenge in the differential diagnoses between B-ALL and other CD5+ B-cell lymphomas with blastic morphology. Dim CD20 and CD45, lack of surface immunoglobulin, expression of CD34 and TdT, negative immunostain for cyclin D1, and absence of t(11;14)(q13;q32) support a diagnosis of B-ALL.

CONCLUSIONS

CD5 expression is rare in B-ALL and associated with poor clinical outcome. CD5+ B-ALL represents a distinct entity that needs to be considered in the differential diagnoses of CD5+ B-cell lymphoproliferative disorders.

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.

Prognostic significance of aberrant CD5 expression in B-cell leukemia

Aberrant expression of CD5 (as a T-cell marker) is seen in some leukemia and lymphoma of B lineage origin. Given that the signaling resulting from the expression of this marker plays an essential role in the development of leukemia and lymphoma, evaluating the expression of this marker is of paramount importance. Therefore, our goal in this study was to investigate the prognostic importance of CD5 expression in B-cell leukemia and lymphoma. We evaluate CD5 expression in normal and leukemic B-cells by identifying relevant literature through a PubMed search (1998-2018) of English language papers using the terms: ‘CD5,’ ‘B-cell,’ ‘Leukemia,’ and ‘Lymphoma.’ We are doing this thorough comparison of results from CD5 positive and negative cases to make a correct decision about prognostic importance of CD5 expression in these malignancies. In a number of B-cell malignancies, CD5 is expressed in varying degrees. Due to the different origins and characteristics of these malignancies, the results of CD5 expression evaluations are heterogeneous and impossible to generalize. However, CD5 expression is sometimes associated with clinicopathologic findings, more invasive clinical course, and even resistance to treatment (specifically in DLBCL) among CD5- positive patients, which appears to be a function of CD5 signaling and its downstream factors such as STAT3. Depending on the type of malignancy, CD5 expression is associated with good or bad prognosis, which can be used as an auxiliary prognostic factor to assess the clinical course of B-cell malignancies. Moreover, the difference in expression levels of CD5 in a variety of B-cell malignancies allows for differential diagnosis of these malignancies, which can be helpful when diagnosis is difficult.

CD5 positive B-ALL, a uniquely aggressive subcategory of B-ALL? A case report and brief review of the literature

CD5 antigen expression in B-cell acute lymphoblastic leukemia (B-ALL) is exceptionally rare. There are six detailed case reports in the literature, with only 16 cases described. Case series analyzing the frequency of aberrant B-ALL immunophenotypes suggest that this variant may occur in as little as 2-4.5% of all B-ALL cases, with one series having no CD5⁺ positive cases. Herein we report a case of CD5⁺ B-ALL in a 15-year-old female, and review the previously reported cases. As limited information is available, more data from prospective clinical trials are required to determine whether CD5 positivity portends a poorer prognosis.

CD5 Positive B Lymphoblastic Leukemia: Report of a Case with Review of Literature

We report a rare CD5 positive B cell acute lymphoblastic leukemia (B-ALL) with a review of the clinopathological features and prognosis of previously reported cases in the literature. The aberrant expression of CD 5 antigen is uncommon in B-ALL; the morphological differential diagnosis includes blastic mantle cell lymphoma, denovo CD5(+) diffuse large B cell lymphoma and secondary diffuse large cell lymphoma/Richter's transformation. CD5(+) B cell ALL is commonly reported in younger patients (<18 years). Though the expression of T cell antigens is reported to have poor prognosis, the experience with CD5(+) B-ALL is limited to draw any firm conclusion regarding its prognosis.

Aberrant Immunophenotypic Expression of CD5 in a Case of B Acute Lymphoblastic Leukemia: A Case Report

Aberrant expression of CD5 has rarely been reported in B cell lineage acute lymphoblastic leukemia (B-ALL). We report the rare immunophenotypic expression of CD5 in a 20-year-old male who was diagnosed to have B-ALL on bone marrow examination. Cytogenetic analysis revealed a mosaic supernumerary marker chromosome. The patient died due to acute pancreatitis after admission. CD5 positive B-ALL may represent a distinct clinicopathologic subcategory of B-ALL with an aggressive clinical course.

MYC rearrangement involving a novel non-immunoglobulin chromosomal locus in precursor B-cell acute lymphoblastic leukemia

MYC rearrangement, a characteristic cytogenetic abnormality of Burkitt lymphoma and several subsets of other mature B-cell neoplasms, typically involves an immunoglobulin gene partner. Herein, we describe a case of precursor B-cell lymphoblastic leukemia harboring a MYC rearrangement with a novel non-immunoglobulin partner locus. The patient was a 4-yr-old Korean boy with ALL of the precursor B-cell immunophenotype. At the time of the second relapse, cytogenetic analyses revealed t(4;8)(q31.1;q24.1) as a clonal evolution. The MYC rearrangement was confirmed by FISH analysis. He died 3 months after the second relapse without achieving complete remission. To our knowledge, this is the first report of a case of MYC rearrangement with a non-immunoglobulin partner in precursor B-cell lymphoblastic leukemia.