[1342] Cytogenetic Analysis of T-Precursor Lymphoblastic Leukemia in Pediatric Patients with Identification of Novel Chromosomal Abnormalities – A Single Institution Experience.

Jyothilekshmi Pillai, Karen Swissheim, Loris McGavran, Xiayuan Liang. The Children's Hospital, Aurora, CO; University of Colorado Denver School of Medicine, Aurora

Background: Several recurrent cytogenetic abnormalities have been reported previously in association with childhood T-acute lymphoblastic leukemia (T-ALL). The most common recurrent cytogenetic abnormality involves the alpha and beta TCR loci at (14)(q11.2), beta locus at (7)(q35), and the gamma locus at (7)(p14-15), with a variety of partner genes. In order to collect more data to get into a deep insight and better understanding of cytogenetic roles in T-ALL, we comprehensively studied karyotypes of childhood T-ALL.
Design: 60 cases of newly diagnosed T-ALL at The Children's Hospital, Colorado from 1996 to 2010 which had chromosomal karyotype available were included in this study.
Results: 40/60 (67%) had abnormal karyotypes. Six novel chromosomal abnormalities are identified. The novel and other recurrent cytogenetic abnormalities are listed in the table.

Table 1

		Our data	Literature data
Newly identified recurrent cytogenetic abnormalities	Tetraploidy (92 chromosome)	2/60 (3%)	None
	1q abnormalities	3/60 (5 %)	None
Novel single translocation	t(1;13)(q12;p12)	1/60 (1.7%)	None
	t(6;15)(q23;p12)	1/60 (1.7%)	None
	t(2;9)(q11.2;q34)	1/60 (1.7%)	None
	t(x;1)(p11.4;q25)	1/60 (1.7%)	None
Other recurrent cytogenetic abnormalities	5q abnormality	3/60 (5 %)	16/354 (5 %)
	del(6q)	8/60 (13%)	67/354 (19 %)
	del(9p)	6/60 (10%)	34/354 (10 %)
	del(11q)	8/60 (13%)	16/354 (5%)
	-9	2/60 (3%)	5/354 (1.4 %)
	-y (male patients)	2/45 (4%)	3/266 (1%)
	+6	2/60 (3%)	Not available
	+10	2/60 (3%)	Not available
	+17	2/60 (3%)	Not available
	+21	2/60 (3%)	10/354 (3%)
	14q11-13	4/60 (7%)	43/354 (12%)
	t(8;14)	2/60 (3%)	Not available
	Hypodiploidy	5/60 (8%)	16/354 (5%)
	Hyperdiploidy	6/60 (10%)	61/354 (17%)

Conclusions: (1) Two novel recurrent cytogenetic abnormalities (tetraploidy and 1q abnormalities) and 4 single novel translocation were identified. (2) del(6q) and del(11q) are the most common recurrent cytogenetic abnormalities of T-ALL in our institution rather than TCR abnormalities reported in the literature. Our data provide new cytogenetic information in childhood T-ALL and may contribute to further understanding of genetic roles in pathogenesis and/or prognosis of this tumor.
Category: Hematopathology

Wednesday, March 2, 2011 9:30 AM

Poster Session V # 160, Wednesday Morning