Clinical Characteristics and Treatment Outcome of Childhood Acute Lymphoblastic Leukemia With the t(4;ll) (q21;q23) By Ching-Hon Pui, Lawrence S. Frankel, Andrew J. Carroll, Susana C. Raimondi, Jonathan J. Shuster, David R. Head, William M. Crist, Vita J. Land, D. Jeanette Pullen, C. Philip Steuber, Frederick G. Behm, and Michael J. Borowitz

INTRODUCTION  Acute lymphoblastic leukemia (ALL) is the most common form of childhood cancer. leukemias.  Leukemia is a cancer of the blood or bone marrow.  It is characterized by an abnormal proliferation (production by multiplication) of blood cells, usually white blood cells white blood cellswhite blood cells

Four major kinds of leukemia Cell type AcuteChronic Lymphocytic leukemia or lymphoblastic Acute lymphoblastic Acute lymphoblastic leukemia (ALL) Chronic lymphocytic leukemia Chronic lymphocytic leukemia (CLL ) Myelogenous leukemia also myeloid or nonlymphocytic Acute myelogenous Acute myelogenous leukemia (AML ) Chronic myelogenous leukemia Chronic myelogenous leukemia (CML) Acute leukemiaAcute leukemia is characterized by the rapid increase of immature blood cells.

Immunological classification of ALL Type of ALL HLA- DR TdTCD10 CD19 a CyIgSIgCD7cCD3 Pro-B- ALL CommonALL Pre-B- ALL B-ALL+0+/-++/-++00 Eerly-T- ALL 0+0/ T-ALLb0+0/+000++

French-American-British (FAB) Classification  L1 Small homogeneous with scanty cytoplasm, moderate basophilia, inconspicuous nuclei.  L2 Larger, heterogeneoys cells, variable cytoplasm, basophilia, prominent nuclei.  L3 Larger, heterogeneoys cells, with dark basophilic cytoplasm, prominent vacules, prominent nuclei.

A translocation involving the long arms of chromosomes 4 and 11- t((4;11)(q21;q23) has been observed in patients with ALL. In a recent review, it was reported that t(4;11) has been observed in 60% of lymphoblastic leukemias in children under the age of 1 year. t(4;11)(q21;q23) ) G-banding (left) - Courtesy Diane H. Norback, Eric B. Johnson, and Sara Morrison- Delap, UW Cytogenetic Services; R- banding (right) - Editor (above), and Courtesy Christiane Charrin (belowUW Cytogenetic Services

Aim of the study  In here, a Collaborative Study of 40 Cases with the t(4;11)(q21;q23) chromosomal abnormality was studied in children with newly diagnosed acute lymphoblastic leukemia (ALL).  This study describe : - The frequency, - The frequency, - Clinical and laboratory features, - Clinical and laboratory features, - And treatment outcome in these 40 cases - And treatment outcome in these 40 cases with t(4;11) )(q21;q23). with t(4;11) )(q21;q23).

SUBJECTS n = 2,724 N = 515 N = 40 N = Total Therapy Studies at St Jude Children's Research Hospital (SJCRH) Pediatric Oncology Group (POG) studies The total number accrued t((4;11)(q21;q23) Have the t((4;11)(q21;q23) were studied

Methods  Morphologic studies -Cases were classified according to French- American-British (FAB) based on bone marrow cell morphology and cytochemical staining characteristics,. -Cases were classified according to French- American-British (FAB) based on bone marrow cell morphology and cytochemical staining characteristics,.  Ficoll-Hypaque gradient : -Bone marrow cells were separated by this method. -Bone marrow cells were separated by this method.

 Flow cytometry -Cell surface antigens were detected -Cell surface antigens were detected by a standard indirect immuno - by a standard indirect immuno - fluorescence assay. fluorescence assay. -were considered positive if they were expressed in 20% or more of the blast cells. -were considered positive if they were expressed in 20% or more of the blast cells. A simplified illustration of Flow Cytometry (Gerstner et al., 2005)

With flowcytometry monoclonal antibodies was used to : With flowcytometry monoclonal antibodies was used to : - lymphoid- associated antigens (CD2, CD5, CD7, CD19, CD20, - lymphoid- associated antigens (CD2, CD5, CD7, CD19, CD20, CD21, CD22, and CD24), CD21, CD22, and CD24), -Myeloid-associated antigens (CD13, CD15, and CD33), and -Myeloid-associated antigens (CD13, CD15, and CD33), and -Nonlineage specific antigens (CD10, CD34, CD45, and HLA-DR). -Nonlineage specific antigens (CD10, CD34, CD45, and HLA-DR). Cells were also tested for cytoplasmic Ig (cIg). Cells were also tested for cytoplasmic Ig (cIg). -Significant cIg expression was defined by the presence -Significant cIg expression was defined by the presence of Ig in the cytoplasm of 10% or more of blasts. of Ig in the cytoplasm of 10% or more of blasts.

Chromosome analysis was done as follows: Processing of only 0.1 ml of sedimented cells or of sedimented cells or less per centrifuge tube. less per centrifuge tube. Exposure of cells to Colcemid to Colcemid for a maximum of 25 min. for a maximum of 25 min. Control of the total time of time of exposure to hypotonic solution. Slide preparation by a specific by a specificedging-flaming technique. technique. The cells were cultured in RPMI 1640 medium. Supplemented with 30% fetal calf serum, to support cellular activity with 30% fetal calf serum, to support cellular activity during specimen transport during specimen transport 1 2 3

- This procedure were finalized by doing natural aging of the slides to achieve optimal drying and use of a modified G-banding procedure that employs Wright's stain. employs Wright's stain.

Results  Of the 1,986 cases studied, 40 (2%) were found to have a leukemic cell line with the t(4;11)(q21;q23). These children (25 girls and 15 boys) ranged in age from 1 month to 14 years 8 months at diagnosis (median, 9 months).  Clinical and Laboratory findings as in the following table:

Cell Immunophenotyping

Discussion  The reported frequency of the t(4;ll) in patients with ALL has ranged from 1.6% to 11% for children, and from 5% to 8% for adults In our study, this chromosomal abnormality occurred in 2%, Thus, the t(4;ll) is one of the most common specific chromosomal translocations in childhood ALL. In our study, this chromosomal abnormality occurred in 2%, Thus, the t(4;ll) is one of the most common specific chromosomal translocations in childhood ALL.  Our patients aged 1 to 9 years had a significantly better treatment outcome than infants and older patients with the t(4;ll). Seven of eight patients in this age group, compared with 9 of the 32 other patients, remain in remission. Thus, the adverse prognosis of the t(4;ll) is related at least in part to its association with the poor-risk age groups. Seven of eight patients in this age group, compared with 9 of the 32 other patients, remain in remission. Thus, the adverse prognosis of the t(4;ll) is related at least in part to its association with the poor-risk age groups.

 Ultrastructural, immunophenotypic, and in vitro culture studies have demonstrated marked lineage heterogeneity in cases with the t(4;ll). -Although many reported cases have had myelomonocytic characteristics, or mixed lineage marker expression most have been classified as B-precursor-cell ALL (CD19+, HLA-DR+). -Although many reported cases have had myelomonocytic characteristics, or mixed lineage marker expression most have been classified as B-precursor-cell ALL (CD19+, HLA-DR+). -Only rarely have or B-cell" phenotypes been reported in patients with this translocation. Indeed, all 35 evaluable cases in this study had B-precursor-cell ALL. -Only rarely have or B-cell" phenotypes been reported in patients with this translocation. Indeed, all 35 evaluable cases in this study had B-precursor-cell ALL. -During this study period, they have not encountered any case of acute myeloid leukemia with the t(4;ll). -During this study period, they have not encountered any case of acute myeloid leukemia with the t(4;ll).

Conclusion  The t(4;ll) is one of the most common nonrandom translocations in childhood ALL, accounting for 2% of newly diagnosed cases.  Cases with the t(4;ll) are associated with female sex, very young age at presentation, hyperleukocytosis, the CDlO - /CD15 + /CD19 + / CD24 -/+ immunophenotype, and poor treatment outcome for infants and patients aged ≥ 10 years.  Additional studies are clearly merited to determine the independent prognostic significance of the t(4;ll) and to assess possible molecular differences in this translocation for different age groups.