t(14;20)(q11.2;q13.3) involving the T-cell receptor α/δ gene in a pediatric acute lymphoblastic leukemia B-cell type

S Adriana Zamecnikova, Soad Al Bahar Affiliation

Kuwait Cancer Control Center, Department of Hematology, Laboratory of Cancer Genetics, Kuwait annaadria@yahoo.com

Previous history

Preleukaemia

Malignant disease

Inborn condition

Clinics case report

Age

1 year 4 month

Sex

Liver

Spleen

Lymph nodes

Cns involv

Blood data

Wbc

82.9

8,6

Platelets

Blasts

83% (neutrophils 2, lymphocytes 10, monocytes 1, myelocytes 2, metamyelocytes 2)

Bone marrow

Bone marrow biopsy and aspirate revealed a hypercellular marrow with 90 % blast cells.

Cyto path

Phenotype

B-ALL

Immunophenotype

Positive for CD 10 (71%), CD19 (80%), CD20 (41%), CD22 (72%), CD79a (81%), CD45 (98%), HLADR (94%), CD34 (33%), TdT (62%).

Survival data

Date diagnosis

02-2016

Status

Karyotype

Sample

Bone marrow

Culture time

Banding

G-banding

Results

46,XX,?del(9)(p21),t(14;20)(q11.2;q13.3)[5]/46,XX,der(9)?del(9)(p11?p23)t(9;20) (p11;q11.2), t(14;20)(q11.2;q13.3)[5]/ 46,XX [10]

Mol cytogenet technics

Fluorescence in situ hybridization (FISH) for LSI CDKN2A (9p21)/CEP9 Dual Color, LSI 20q, LSI IGH Dual Color, Break Apart (BA), WCP 20 and LSI TCR alpha/delta Dual Color, Break Apart Rearrangement probes (Vysis/Abbott Molecular, Des Plaines, IL, USA) according to standard techniques.

Mol cytogenet results

Applying the LSI TCR A/D-specific BA probe on interphase cells revealed 1 red, 1 green and 1 fusion signal pattern in 80% of cells, indicative of TCR α/δ rearrangement. Applying the LSI CDKN2A (9p21)/CEP9 probe on interphase cells revealed 2 signals (green) for chromosome 9 centromere and no red signal for CDKN2A (9p21) in 70% of cells. FISH analysis with combination of LSI TCR A/D BA and LSI CDKN2A (9p21)/CEP9 probes revealed juxtaposition of telomeric TCR sequences (green) to the der(20) chromosome as a result of t(14;20)(q11.2;q13) and 2 green chromosome 9 centromere signals, while no red signal for CDKN2A (9p21) was detected on 5 metaphases (Figure 2A). Applying the LSI 20q probe located on 20q12 revealed 2 normal signals in 98% of interphase cells. Hybridization with LSI 20q12 probe (red signals) on metaphases revealed one signal of 20q12 on der(20)t(14;20) chromosome and the other 20q12 signal on der(9) chromosome. Hybridization with LSI 20q probe on metaphases confirmed the presence of 20q12 signals (red) on der(20)t(14;20) and der(9)t(9;20) chromosomes (Figure 1B). Additional FISH analyses on 5 metaphases by using the WCP 20 and CDKN2A (9p21)/CEP9 probes (Figure 2C) confirmed the presence of chromosome 20 sequences in der(20)t(14;20) and der(9)t(9;20) chromosomes with simultaneous deletion of 9p21 sequences (no red signal was detected on chromosomes 9).

Images

G-banded karyotype of the patient with t(14;20)(q11.2;q13.3) and partial karyotypes with t(9;20)(p11;q11),t(14;20)(q11.2;q13.3).

FISH analysis was performed to determine the breakpoints on 14q using a T-cell receptor alpha delta (TCR A/D) DNA Probe, revealing split signal as a result of t(14;20)(q11.2;q13.3) and hybridization with the LSI CDKN2A (9p21)/CEP9) probe showed homozygous deletions of 9p21 indicative of biallelic deletion of genes from 9p21 (Figure 1A). Simultaneous hybridization with LSI IGH and 20q12 probes revealed one signal of IGH on der(20)t(14;20) chromosome distal to the 20q12 signal (red) and the other 20q12 signal on der(9) chromosome (Figure 1B1). Alternatively: hybridization with LSI 20q12 probe revealed one signal of 20q12 on der(20)t(14;20) chromosome (red) and the other 20q12 signal on der(9) chromosome (Figure 1B2). Hybridization with WCP 20 and CDKN2A (9p21)/CEP9 probes confirmed the juxtaposition of chromosome 20 sequences to der(20)t(14;20) and der(9)t(9;20) chromosomes with simultaneous deletion of 9p21 sequences (Figure 1C).

Comments section

Comments

Rearrangements of the T-cell receptor α/δ genes has been only rarely observed in B-cell malignancies. We describe a B-cell ALL patient with t(14;20)(q11.2;q13.3) and t(9;20)(p11;q11) in whom FISH studies confirmed TCR α/δ disruption and homozygous deletions of 9p21. The t(14;20)(q11.2;q13) have been reported only in 2 (Erikson et al., 1986; Douet-Guilbert et al., 2004), while translocations between 9p11-21 and 20q have been found only in 4 patients (Horiike et al., 1988; UKCCG., 1992; Gardiner et al., 2012; Le Noir et al., 2012). Among them, Le Noir et al., described a T-ALL case with simultaneous t(9;20)(p21;q12) and TCR α/δ disruption. The coexistence of 9p21 deletion and TCR α/δ rearrangement in our patient may indicate cooperative oncogenesis between gene inactivation and oncogene activation in ALL.

Bibliography

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3513189	1986	Heterogeneity of chromosome 22 breakpoint in Philadelphia-positive (Ph+) acute lymphocytic leukemia.	Erikson J et al
3409186	1988	Chromosome abnormalities and karyotypic evolution in 83 patients with myelodysplastic syndrome and predictive value for prognosis.	Horiike S et al
1384680	1992	Translocations involving 9p and/or 12p in acute lymphoblastic leukemia. United Kingdom Cancer Cytogenetics Group (UKCCG).
21796768	2012	Using MS-MLPA as an efficient screening tool for detecting 9p21 abnormalities in pediatric acute lymphoblastic leukemia.	Gardiner RB et al
22948044	2012	Extensive molecular mapping of TCRα/δ- and TCRβ-involved chromosomal translocations reveals distinct mechanisms of oncogene activation in T-ALL.	Le Noir S et al

Citation

S Adriana Zamecnikova, Soad Al Bahar

t(14;20)(q11.2;q13.3) involving the T-cell receptor α/δ gene in a pediatric acute lymphoblastic leukemia B-cell type

Atlas Genet Cytogenet Oncol Haematol. 2016-05-01

Online version: http://atlasgeneticsoncology.org/case-report/208885/t(14;20)(q11-2;q13-3)-involving-the-t-cell-receptor-gene-in-a-pediatric-acute-lymphoblastic-leukemia-b-cell-type