Submicroscopic deletions at 7q region are associated with recurrent chromosome abnormalities in acute leukemia.
OBJECTIVE
Loss of heterozygosity (LOH) on the long arm of chromosome 7 (7q) has been frequently reported in several types of human cancer including hematologic malignancies. Moreover, monosomy of chromosome 7 and 7q deletions have been associated in acute myeloid leukemia (AML) with aggressive disease and poor prognosis.


METHODS
Using a panel of 11 polymorphic microsatellite markers at bands 7q21-q36, we investigated fifty patients (acute myeloid leukemia [AML], n=33 and acute lymphoid leukemia [ALL], n=17) for LOH, a hallmark of possible involvement of tumor suppressor genes. In parallel, the same acute leukemia (AL) cases were studied by conventional cytogenetics.


RESULTS
A total of 48 spots of allelic loss were observed in 16 (32%) out of 50 patients (AML, n=11 and ALL, n=5). Among LOH+ve cases 3 showed chromosome 7 monosomies, whereas no cytogenetically detectable abnormalities were observed in chromosome 7 in the remaining 13.


CONCLUSIONS
Comparison with karyotypic results indicated that presence of LOH at 7q21-q36 was significantly associated with other chromosomal aberrations. In fact, an altered karyotype was detectable in 87% of LOH+ve and in 52% of LOH(-ve) AL cases (p=0.024). In addition, LOH at 7q was prevalently associated with unfavorable cytogenetic lesions (p=0.013). Our study represents the first report of a significant association between LOH and recurrent chromosomal abnormalities in AL patients suggesting that the 7q21-q36, region may be an unstable area prone to chromosome breakage in patients with an abnormal karyotype.
Basiricò
Rosaria
R
Division of Hematology and BMT Unit, Ospedale "V. Cervello", Palermo, Italy.
Pirrotta
Rosa
R
Fabbiano
Francesco
F
Mirto
Salvo
S
Cascio
Lucia
L
Pagano
Maria
M
Cammarata
Giuseppe
G
Magrin
Silvana
S
Santoro
Alessandra
A
D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002869:Chromosome Aberrations; D002897:Chromosomes, Human, Pair 7; D020732:Cytogenetic Analysis; D005260:Female; D006801:Humans; D007938:Leukemia / Q000235:genetics*; D019656:Loss of Heterozygosity / Q000235:genetics; D008297:Male; D008875:Middle Aged; D012008:Recurrence; D017384:Sequence Deletion