[The different signal patterns of two FISH probes in the FISH detection of Ph-positive leukemia and their clinical significance].
OBJECTIVE
To compare the signal patterns of dual color extra-signal BCR/ABL probe (ES-FISH) and dual color dual fusion BCR/ABL probe (D-FISH) in the fluorescence in situ hybridization (FISH) detection of Ph-positive leukemia, and to explore their diagnostic value.


METHODS
ES-FISH probe and D-FISH probe were used, respectively, to detect the BCR/ABL fusion gene in 74 cases with typical t(9;22)(q34;q11) and 37 cases with variant t(9;22)(q34;q11) translocation or complex karyotypic abnormalities containing Ph translocation.


RESULTS
The BCR/ABL fusion gene in all cases with typical t(9;22)(q34;q11) could be detected by both FISH probes. D-FISH had a signal pattern of 1O1G2F, while ES-FISH showed a signal pattern of 2O1G1F. ES-FISH enables the minor breakpoint cluster region to be identified in 9 cases (12.2% ) of Ph-positive leukemia, whereas D-FISH could not differentiate the minor breakpoint cluster region from major breakpoint cluster region. D-FISH could distinguish simple ABL gene deletion from simultaneous deletion of the ABL and BCR genes in 8 cases (10.8%) of Ph-positive leukemia patients, but ES-FISH could not. For variant Ph translocation or complex karyotypic abnormalities containing Ph translocation, each FISH probe showed four or six types of signal pattern, most of which were atypical. The exact interpretation was dependent on conventional karyotypic analysis and FISH on metaphases.


CONCLUSIONS
ES-FISH and D-FISH probes displayed different signal patterns in Ph-positive leukemia due to their differences in size and covered regions. ES-FISH and D-FISH probes may be selected as better probe for Ph-positive acute lymphocytic leukemia and Ph-positive chronic myeloid leukemia, respectively. When imatinib was used for treatment, there was no preference between ES-FISH and D-FISH probe, because major breakpoint cluster region, minor breakpoint cluster region and partial sequence deletion of derivative chromosome 9, would not affect the prognosis of Ph-positive leukemia. However, considering that ES-FISH probe has a better cost-performance than D-FISH probe does, it is recommended as first choice.
Jiang
Hui
H
Jiangsu Institute of Hematology, the First Affiliated Hospital of Soochow University, Thrombosis and Hemostasis Key Laboratory of the Ministry of Health, Soochow University, Suzhou, Jiangsu, P.R. China.
Xue
Yong-quan
YQ
Pan
Jin-lan
JL
Zhang
Jun
J
Dai
Hai-ping
HP
Wu
Ya-fang
YF
Wang
Yong
Y
Shen
Juan
J
Chen
Su-ning
SN
D016022:Case-Control Studies; D002899:Chromosomes, Human, Pair 9 / Q000235:genetics; D006801:Humans; D017404:In Situ Hybridization, Fluorescence / Q000379:methods*; D007621:Karyotyping; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000175:diagnosis* / Q000235:genetics*; D051562:Proto-Oncogene Proteins c-bcr / Q000235:genetics
D051562:Proto-Oncogene Proteins c-bcr