Translocation t(7;9)(q34;q32) found in pediatric T-cell Acute Lymphoblastic Leukemia

2007-09-01  Jennifer JS Laffin, Randee J Blumer, Sara J Morrison-Delap, Elizabeth A Rauch, Eric B Johnson, Carol A Diamond, Kate J Thompson, Gordana Raca, Karen D Montgomery, Daniel F Kurtycz

University of Wisconsin-Madison, School of Medicine and Public Health, Department of Pediatrics, University of Wisconsin Cytogenetic Services, Wisconsin State Laboratory of Hygiene, Madison, WI, USA (JJSL)(CAD); University of Wisconsin Cytogenetic Services, Wisconsin State Laboratory of Hygiene, Madison, WI, USA (RJB)(SJMD)(EAR)(EBJ)(KJT); University of Wisconsin-Madison, School of Medicine and Public Health, Department of Pathology and Laboratory Medicine, University of Wisconsin Cytogenetic Services, Wisconsin State Laboratory of Hygiene, Madison, WI, USA (GR)(KDM)(DFK)

Previous history

Preleukaemia
-
Malignant disease
-
Inborn condition
-

Clinics case report

Age
4 yrs
Sex
F
Liver
+
Spleen
+
Lymph nodes
+
Cns involv
-

Blood data

Wbc
148
Hb
9.8
Platelets
13
Blasts
peripheral 60%
Bone marrow
100%

Cyto path

Cytology
L2
Immunophenotype
NK+, CD2, CD3, CD4, CD5, CD7, CD8, and TdT+
Precise diagnosis
Acute Lymphoblastic Leukemia, L2

Survival data

Date diagnosis
02-2006
Treatment
chemotherapy (intrathecal and systemic), cranial X-ray therapy, and allogenic stem cell transplant
Relapse
+ central nervous system (8/06 with cytogenetics) and bone marrow relapse
Status
A
Date last follow
08-2007
Survival
31 to date

Karyotype

Sample
diagnostic sample was of bone marrow
Culture time
analysis of diagnostic sample was performed on overnight colcemid, 18-hour and 72-hour cultures
Banding
350 band level
Results
46,XX,t(7;9)(q34;q31~q32)[16]/46,XX[4]
Karyotype relapse
Date: 08-2006; Result: 46,XX,del(6)(q21),t(7;9)(q34;q31~q32)[cp2]/46,XX[19]

Images

Atlas Image
Partial karyotypes of metaphases from diagnostic sample overnight colcemid culture.

Comments section

Comments
The patient presented in this case report has features consistent with other reported cases of T cell acute lymphoblastic leukemia (T-ALL) with t(7;9)(q34;q32) involving the TCRbeta locus on 7q34 and the TAL2 gene on 9q34. In particular, review of the literature revealed a case in a 3 year old male with similar clinical and hematological findings and the same additional cytogenetic anomaly, del(6)(q21). Approximately 60% of clinically normal individuals have t(7;9)(q34;q32) created by V(D)J recombination which uses a fortuitous recombination site (RSS) located 3 of the TAL2 oncogene. In T-ALL affected individuals a rare second rearrangement occurs between the junction point of the original t(7;9) and Jbeta2. This brings the TAL2 gene under the control of TCRbeta enhancer, and leads to its inappropriate expression.

Article Bibliography

Pubmed IDLast YearTitleAuthors
29626501988Clinical and biologic characterization of T-cell neoplasias with rearrangements of chromosome 7 band q34.Smith SD et al
125671872003Distinct t(7;9)(q34;q32) breakpoints in healthy individuals and individuals with T-ALL.Marculescu R et al

Citation

Jennifer JS Laffin, Randee J Blumer, Sara J Morrison-Delap, Elizabeth A Rauch, Eric B Johnson, Carol A Diamond, Kate J Thompson, Gordana Raca, Karen D Montgomery, Daniel F Kurtycz

Translocation t(7;9)(q34;q32) found in pediatric T-cell Acute Lymphoblastic Leukemia

Atlas Genet Cytogenet Oncol Haematol. 2007-09-01

Online version: http://atlasgeneticsoncology.org/case-report/208830/translocation-t(7